canSAS - Recent changes [en]

Grazing Incidence Working Group

AdrianRennie — Mon, 20 Apr 2026 11:34:07 GMT

/GISANS - Advancing data reduction and analysis Workshop

AdrianRennie — Mon, 20 Apr 2026 11:29:45 GMT

Outlook and work to be done: correct typo

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canSAS

AdrianRennie — Fri, 17 Apr 2026 11:35:12 GMT

Change tense for a past meeting

← Older revision		Revision as of 11:35, 17 April 2026
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	==News==		==News==

	A workshop on '''GISANS - Advancing Data Reduction and Analysis: [https://workshops.ill.fr/event/573/] ~~will take~~ place 18-19 March 2026 in Grenoble with possibilities for remote participation.'''		A workshop on '''GISANS - Advancing Data Reduction and Analysis: [https://workshops.ill.fr/event/573/] took place on 18-19 March 2026 in Grenoble with possibilities for remote participation.'''

	'''SAS2024: [https://www.sas2024.tw SAS 2024] took place Nov 3-8, 2024 in Taipei Taiwan.'''		'''SAS2024: [https://www.sas2024.tw SAS 2024] took place Nov 3-8, 2024 in Taipei Taiwan.'''

/GISANS - Advancing data reduction and analysis Workshop

AdrianRennie — Sun, 12 Apr 2026 12:55:45 GMT

← Older revision		Revision as of 12:55, 12 April 2026
(3 intermediate revisions by the same user not shown)
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	(i) ToF		(i) ToF
	* Instrument factors influence measurement strategies and tools are needed to aid this process.		* Instrument factors influence measurement strategies and tools are needed to aid this process.
	* Background - effects of inelastic scattering can change background.		* Background - effects of inelastic scattering can change background signals that would not be identified/recorded correctly with respect to wavelength by time-of-flight.
	* Resolution is important regarding both wavelength and angle. The latter depends on collimation/beam divergence as well as footprint on the sample and spatial resolution of the detector. The footprint depends on angle of incidence. The footprint gives some spatial and angular resolution projected on the detector.		* Resolution is important regarding both wavelength and angle. The latter depends on collimation/beam divergence as well as footprint on the sample and spatial resolution of the detector. The footprint depends on angle of incidence. The footprint gives some spatial and angular resolution projected on the detector.
	Full interpretation of data is likely to require extensive information to be available with processed data.		Full interpretation of data is likely to require extensive information to be available with processed data.
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	(ii) Multiple scattering		(ii) Multiple scattering
	* Reflection and refraction should be ~~excluded~~ from multiple scattering		* Reflection and refraction (optical effects) should be distinguished from multiple scattering
	* ~~Need~~ to agree on a common nomenclature		* There is a need to agree on a common nomenclature
	* “Coherent multiple scattering” ~~refers~~ to the situation in which successive scattering events are not treated independently but are combined quantum mechanically, i.e., the amplitudes from different scattering paths are added coherently.		** “Coherent multiple scattering” can refer to the situation in which successive scattering events are not treated independently but are combined quantum mechanically, i.e., the amplitudes from different scattering paths are added coherently. This use of "coherence" has to be distinguished from others such as simple spin-coherence widely discussed in neutron scattering.
	* Sub-cases of multiple coherent scattering: (i) ~~the~~ propagation of the incident wave through ~~the~~ stratified ~~medium~~, which is incorporated ~~_exactly_~~ in the formalism; and (ii) ~~the~~ scattering from embedded “particles” (additional scattering centers) which is treated ~~perturbatively~~ within the 1st-order Born approximation. Both (i) and (ii) are within the quantum theory (‘coherent’).		** Sub-cases of multiple coherent scattering: (i) propagation of the incident wave through stratified media, which is incorporated exactly in the optical formalism treating reflection and refraction; and (ii) scattering from embedded “particles” (additional scattering centers) which is treated as a perturbation within the 1st-order Born approximation. Both (i) and (ii) are within the quantum theory (‘coherent’).
	* “Incoherent multiple scattering” denotes an approximation in which scattering from each center is treated ~~quantum mechanically~~, but the subsequent propagation of scattered waves is represented within a semi-classical or ray-optical picture (Gaussian optics). This approach is conceptually analogous to the semi-classical treatment of transport phenomena based on the Boltzmann equation, where phase relations between successive scattering events are neglected.		** “Incoherent multiple scattering” denotes an approximation in which scattering from each center is treated, but the subsequent propagation of scattered waves is represented within a semi-classical or ray-optical picture (Gaussian optics). This approach is conceptually analogous to the semi-classical treatment of transport phenomena based on the Boltzmann equation, where phase relations between successive scattering events are neglected. The result corresponds to summing intensities rather than amplitudes of scattered waves.
	* There are ~~certain constraints for~~ multiple scattering: mean free path length & coherence length, sample size ~~/ curvature~~ / geometry
			* There are several factors that influence multiple scattering: mean free path length & coherence length, sample size / geometry
	** They have to be identified before each experiment		** They have to be identified before each experiment
	* ~~MS gives extra~~ background: can be used to explicitly enhance signal		* Multiple scattering is often present in background signals. It can be used also to explicitly enhance signal
	* X-~~ray comparison~~:		* comparison of X-rays and neutrons:
	** X-rays: (mostly) strong absorption		** X-rays: (mostly) strong absorption
	** Neutrons:		** Neutrons:
	*** ~~absorption~~ is weak and therefore scattering is of higher intensity.		*** Absorption is often weak and therefore, scattering is relative to absorption, of higher intensity.
	*** Hydrogen ~~absorption~~ strong		*** Hydrogen is a particularly strong incoherent scattering nucleus
	** Be careful when comparing the theory from GISAXS and GISANS!		** Be careful when comparing the theory from GISAXS and GISANS!
	* How to measure MS?		* How to measure MS?
	** GIXOS (grazing incidence X-ray offspecular scattering)		* For multiple scattering it can be useful to include Monte Carlo calculations such as McStas as tool for GISANS analysis.
	*** Scattering from the object is modulated by the reflectivity, you can ~~deduce reflectivity if you estimate the form factor~~.
	*** Example: ID10 ESRF		*** Example: ID10 ESRF

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	** sample system/geometry/the observable physics.		** sample system/geometry/the observable physics.
	* Each system has to be treated in a different way.		* Each system has to be treated in a different way.
	* Useful recent work (Jung and Papadakis, J. Appl. Cryst. (2023) 56, 1330–1347) regarding strategy to handle background for fits and simulations to GISAXS patterns.		* Useful recent work (F. A. Jung and C. M. Papadakis, 'Strategy to simulate and fit 2D grazing-incidence small-angle X-ray scattering patterns of nanostructured thin films' J. Appl. Cryst. (2023) 56, 1330–1347. https://doi.org/10.1107/S1600576723006520 ) regarding strategy to handle background for fits and simulations to GISAXS patterns.
	* A survey ~~will~~ help ~~identifying~~ the necessary / common steps among the community for specific classified systems.		* A survey would help to identify the necessary / common steps among the community for specific classified systems.
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?

	(iv) Normalization		(iv) Normalization
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	** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.		** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.
	*** In NR: fit the data+background to the total signal (instead of subtracting!)		*** In NR: fit the data+background to the total signal (instead of subtracting!)
	** ~~GISOXS~~?		** GIXOS?
	* If this is not feasible:		* If this is not feasible:
	** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed! (Different normalization procedures at different beamlines and for different classes of systems)		** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed! (Different normalization procedures at different beamlines and for different classes of systems)
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	* Regarding BornAgain:		* Regarding BornAgain:
	** Need a set of prototype models (check what is on the BA webpage) - especially for inexperienced users		** Need a set of prototype models (check what is on the BA webpage) - especially for inexperienced users
	*** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if ~~overgone~~.		*** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if beyond range.
	*** Can we benefit from models in other software packages?		*** Can we benefit from models in other software packages?
	*** SasView: easy user-insertions of new form-factors - learn from that?		*** SasView: easy user-insertions of new form-factors - learn from that?
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	(vii) Common data format		(vii) Common data format
	* Pros and Cons of ~~seperating~~ "reduction" and "analysis", i.e., having an instrument independent analysis without original raw information		* Pros and Cons of separating "reduction" and "analysis", i.e., having an instrument independent analysis without original raw information
	** Pro:		** Pro:
	*** datasets are transferable between softwares		*** datasets are transferable between softwares

/GISANS - Advancing data reduction and analysis Workshop

Apostolos Vagias — Wed, 08 Apr 2026 22:27:02 GMT

Summary

← Older revision		Revision as of 22:27, 8 April 2026
(5 intermediate revisions by the same user not shown)
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	* Instrument factors influence measurement strategies and tools are needed to aid this process.		* Instrument factors influence measurement strategies and tools are needed to aid this process.
	* Background - effects of inelastic scattering can change background.		* Background - effects of inelastic scattering can change background.
	* Resolution is important both ~~as regards~~ wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.		* Resolution is important regarding both wavelength and angle. The latter depends on collimation/beam divergence as well as footprint on the sample and spatial resolution of the detector. The footprint depends on angle of incidence. The footprint gives some spatial and angular resolution projected on the detector.
			Full interpretation of data is likely to require extensive information to be available with processed data.
	* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.		* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.
	* ToF and mono mode have different data processing requirements!		* ToF and mono mode have different data processing requirements!
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	(ii) Multiple scattering		(ii) Multiple scattering
	* Reflection and refraction should be excluded from multiple scattering		* Reflection and refraction should be excluded from multiple scattering
	* Need to agree on a common nomenclature		* Need to agree on a common nomenclature
			* “Coherent multiple scattering” refers to the situation in which successive scattering events are not treated independently but are combined quantum mechanically, i.e., the amplitudes from different scattering paths are added coherently.
			* Sub-cases of multiple coherent scattering: (i) the propagation of the incident wave through the stratified medium, which is incorporated _exactly_ in the formalism; and (ii) the scattering from embedded “particles” (additional scattering centers) which is treated perturbatively within the 1st-order Born approximation. Both (i) and (ii) are within the quantum theory (‘coherent’).
			* “Incoherent multiple scattering” denotes an approximation in which scattering from each center is treated quantum mechanically, but the subsequent propagation of scattered waves is represented within a semi-classical or ray-optical picture (Gaussian optics). This approach is conceptually analogous to the semi-classical treatment of transport phenomena based on the Boltzmann equation, where phase relations between successive scattering events are neglected.
	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry		* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry
	** They have to be identified before each experiment		** They have to be identified before each experiment
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	** Neutrons:		** Neutrons:
	*** absorption is weak and therefore scattering is of higher intensity.		*** absorption is weak and therefore scattering is of higher intensity.
	*** ~~Hydrogenabsorption~~ strong		*** Hydrogen absorption strong
	** Be careful when comparing the theory from GISAXS and GISANS!		** Be careful when comparing the theory from GISAXS and GISANS!
	* How to measure MS?		* How to measure MS?
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	** sample system/geometry/the observable physics.		** sample system/geometry/the observable physics.
	* Each system has to be treated in a different way.		* Each system has to be treated in a different way.
			* Useful recent work (Jung and Papadakis, J. Appl. Cryst. (2023) 56, 1330–1347) regarding strategy to handle background for fits and simulations to GISAXS patterns.
	* A survey will help identifying the necessary / common steps among the community for specific classified systems.		* A survey will help identifying the necessary / common steps among the community for specific classified systems.
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?		* In case of multiple scattering: Include McStas as standard for GISANS analysis?
Line 40:		Line 45:
	* Full quantitative normalization procedure:		* Full quantitative normalization procedure:
	** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.		** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.
	*** In NR: fit the data+background to the total signal (instead of ~~substracting~~!)		*** In NR: fit the data+background to the total signal (instead of subtracting!)
	** GISOXS?		** GISOXS?
	* If this is not feasible:		* If this is not feasible:
	** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed! (Different normalization procedures at different beamlines)		** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed! (Different normalization procedures at different beamlines and for different classes of systems)
	* General aspects (sample independent):		* General aspects (sample independent):
	** Precise I(lambda) normalization of the beamlines has to be performed		** Precise I(lambda) normalization of the beamlines has to be performed
	** Good to get a Survey "How is this done at different beamlines currently"?		** Good to get a Survey "How is this done at different beamlines currently"?
	** Using AI?: Should then contain: (i) dataset that is similar to the experiments (ii) what this data-set represents (physically)		** Using AI?: Should then contain: (i) dataset that is similar to the experiments and (ii) what this data-set represents (physically)

	* Data-reduction:		* Data-reduction:
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	* Maybe not "throw away" raw counts after reduction, but keep all information? If suitable / manageable: Ask in Survey?		* Maybe not "throw away" raw counts after reduction, but keep all information? If suitable / manageable: Ask in Survey?

	(ix) Magnetic Scattering]		(ix) Magnetic Scattering
	* considering ".nxs" files and dimensions: A scan of everything/motor should be considered a dimension in the "nxs". It should not be restricted to 4 dimensions.		* considering ".nxs" files and dimensions: A scan of everything/motor should be considered a dimension in the "nxs". It should not be restricted to 4 dimensions.
	* On-the-fly polarization analysis: online corrections are good. But highest precision correction should be done at the end of the experiment before the users go home.		* On-the-fly polarization analysis: online corrections are good. But highest precision correction should be done at the end of the experiment before the users go home.
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	* Presentation slides:		* Presentation slides:
	[[File:2026 03 CANSAS Grenoble Data Reduction TOF JFMoulin.pdf\|thumb\|Introduction to ToF Data Reduction - Jean-Francois Moulin]]		[[File:2026 03 CANSAS Grenoble Data Reduction TOF JFMoulin.pdf\|thumb\|Introduction to ToF Data Reduction - Jean-Francois Moulin]]
			[[File:2026 03 12 Monochromatic GISANS reduction v4.pdf\|thumb]]
	* Further Notes from the ILL-Workshop on: [[/Notes Data Reduction]]		* Further Notes from the ILL-Workshop on: [[/Notes Data Reduction]]

	==== Organizational notes ====		==== Organizational notes ====

File:2026 03 12 Monochromatic GISANS reduction v4.pdf

Apostolos Vagias — Wed, 08 Apr 2026 22:01:33 GMT

Apostolos Vagias uploaded File:2026 03 12 Monochromatic GISANS reduction v4.pdf

New page

Koutsioumpas, Vagias, Gutfreund - Monochromatic GISANS reduction

/GISANS - Advancing data reduction and analysis Workshop

Annikastellhorn — Tue, 07 Apr 2026 10:58:26 GMT

Show changes

/Normalization

Apostolos Vagias — Tue, 07 Apr 2026 08:14:31 GMT

← Older revision		Revision as of 08:14, 7 April 2026
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	* Regarding the question "can magnetic references help" - this can not generally be done, as changing the layer system would impact on the sld, the background, the normalization, etc.		* Regarding the question "can magnetic references help" - this can not generally be done, as changing the layer system would impact on the sld, the background, the normalization, etc.
	* Does the "correct normalization" only get critical if the background level is that high that changing the background in the simulation would change the simulated sld? Is that the same in NR and GISANS?		* Does the "correct normalization" only get critical if the background level is that high that changing the background in the simulation would change the simulated sld? Is that the same in NR and GISANS?
	* What can you get from Q=0 in a GISANS measurement? Can one at all extract a ~~quantitave~~ solution from a GISANS measurement? Should rather we aim at always having proper reference systems that the cross section can be compared with for getting the physical parameters needed?		* What can you get from Q=0 in a GISANS measurement? Can one at all extract a quantitative solution from a GISANS measurement? Should rather we aim at always having proper reference systems that the cross section can be compared with for getting the physical parameters needed?

	Notes group (?):		Notes group (?):

/Background handling

Apostolos Vagias — Tue, 07 Apr 2026 08:07:52 GMT

← Older revision		Revision as of 08:07, 7 April 2026
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	** sample system/geometry/the observable physics.		** sample system/geometry/the observable physics.
	* Each system has to be treated in a different way.		* Each system has to be treated in a different way.
	* A survey will help identifying the necessary / common steps among the community for specific classified systems.		* A survey will help identifying the necessary / common steps among the community for specific classified systems. Potentially very helpful input for GISANS from a recent paper (Jung and Papadakis, J. Appl. Cryst. (2023). 56, 1330–1347) regarding strategy to simulate and fit GISAXS patterns.
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?		* In case of multiple scattering: Include McStas as standard for GISANS analysis?

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	* how to judge if the simulation (even if fitting perfectly to the data) is the physical correct one? For the question of which parameters are influencing the cross section mostly using bayesian fitting: see papers from Josh (for reflectometry): https://journals.iucr.org/j/issues/2021/04/00/ge5096/ge5096sup1.pdf		* how to judge if the simulation (even if fitting perfectly to the data) is the physical correct one? For the question of which parameters are influencing the cross section mostly using bayesian fitting: see papers from Josh (for reflectometry): https://journals.iucr.org/j/issues/2021/04/00/ge5096/ge5096sup1.pdf
	* X-ray community:		* X-ray community:
			** Very helpful the recent work (Jung and Papadakis, J. Appl. Cryst. (2023). 56, 1330–1347) regarding strategy to simulate and fit GISAXS patterns, potentially very helpful for GISANS.
	** Grazing incidence background subtraction is very difficult already in the X-ray techniques. State of the art for X-ray techniques is looking for areas around the strong peaks. This solution is not optimal. You can’t put down the sample and so the best situation is to do the same experiment at a liquid-liquid interface with motion. Everything is in the same place, you put only the liquids in the same cell, GISAXS image with everything except the molecule which will be placed at the interface. Then make a new sample with the same position of the interface with an added molecule. The background sample has to be as close to the real sample as possible. = To have more information, not to be taken as the recipe for handling background.		** Grazing incidence background subtraction is very difficult already in the X-ray techniques. State of the art for X-ray techniques is looking for areas around the strong peaks. This solution is not optimal. You can’t put down the sample and so the best situation is to do the same experiment at a liquid-liquid interface with motion. Everything is in the same place, you put only the liquids in the same cell, GISAXS image with everything except the molecule which will be placed at the interface. Then make a new sample with the same position of the interface with an added molecule. The background sample has to be as close to the real sample as possible. = To have more information, not to be taken as the recipe for handling background.
	** Surface scattering needs to be known to disentangle it from reflection.		** Surface scattering needs to be known to disentangle it from reflection.

/GISANS - Advancing data reduction and analysis Workshop

Annikastellhorn — Tue, 07 Apr 2026 08:04:00 GMT

← Older revision		Revision as of 08:04, 7 April 2026
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	* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.		* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.
	* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.		* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.
			* ToF and mono mode have different data processing requirements!
			** Spread of wavelength in ToF = possible quasi elastic events vs. Mono = assumption of elastic scattering
			** this mostly impacts on Background: mostly inelastic

	(ii) Multiple scattering		(ii) Multiple scattering
	* Reflection and refraction should be excluded from multiple scattering		* Reflection and refraction should be excluded from multiple scattering
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	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry		* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry
	** They have to be identified before each experiment		** They have to be identified before each experiment
			* MS gives extra background: can be used to explicitly enhance signal
			* X-ray comparison:
			** X-rays: (mostly) strong absorption
			** Neutrons:
			*** absorption is weak and therefore scattering is of higher intensity.
			*** Hydrogenabsorption strong
			** Be careful when comparing the theory from GISAXS and GISANS!
			* How to measure MS?
			** GIXOS (grazing incidence X-ray offspecular scattering)
			*** Scattering from the object is modulated by the reflectivity, you can deduce reflectivity if you estimate the form factor.
			*** Example: ID10 ESRF

	(iii) Background handling		(iii) Background handling
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	* A survey will help identifying the necessary / common steps among the community for specific classified systems.		* A survey will help identifying the necessary / common steps among the community for specific classified systems.
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?		* In case of multiple scattering: Include McStas as standard for GISANS analysis?

	(iv) Normalization		(iv) Normalization
	* Full quantitative normalization procedure:		* Full quantitative normalization procedure:
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	* General aspects (sample independent):		* General aspects (sample independent):
	** Precise I(lambda) normalization of the beamlines has to be performed		** Precise I(lambda) normalization of the beamlines has to be performed

	(v) Using SANS software		(v) Using SANS software
	* Regarding BornAgain:		* Regarding BornAgain:
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	** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if overgone.		** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if overgone.
	** Further good features to implement: (i) intensity w.r.t. direct beam, w.r.t multiple scattering background, w.r.t. general expected background (according to experience + commissioning).		** Further good features to implement: (i) intensity w.r.t. direct beam, w.r.t multiple scattering background, w.r.t. general expected background (according to experience + commissioning).
			* Inspiration from X-ray programs: Brookhaven, Ben Ocko, BornAgain

	(vi) Instrumentation		(vi) Instrumentation
	* Missing		* Missing

/ToF-GISANS

Apostolos Vagias — Tue, 07 Apr 2026 07:58:13 GMT

← Older revision		Revision as of 07:58, 7 April 2026
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	Detailed notes group (?):		Detailed notes group (?):
	* ToF and mono mode - different data processing requirements. You have a spread of WL, an event mode dataset, whether it is quasi elastically scattered when it arrives on the detector. Mono instrument with no WL recording: making an assumption the signal is elastic. Elastic scattering is predominant but the background its often inelastic.		* ToF and mono mode - different data processing requirements. You have a spread of wavelength (WL), an event mode dataset, whether it is quasi elastically scattered when it arrives on the detector. Mono instrument with no WL recording: making an assumption the signal is elastic. Elastic scattering is predominant but the background its often inelastic.

/Multiple Scattering

Apostolos Vagias — Tue, 07 Apr 2026 07:50:04 GMT

← Older revision		Revision as of 07:50, 7 April 2026
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	* Reflection and refraction should be excluded from multiple scattering		* Reflection and refraction should be excluded from multiple scattering
	* Need to agree on a common nomenclature		* Need to agree on a common nomenclature
			* Need to distinct between coherent multiple scattering (whether as propagation through stratified medium or scattering from different embedded particles) and incoherent multiple scattering
	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry		* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry
	** They have to be identified before each experiment		** They have to be identified before each experiment
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	*** When you move a liquid surface and wait for it to stop, the measurement duty cycle is poor (2 min vs seconds)		*** When you move a liquid surface and wait for it to stop, the measurement duty cycle is poor (2 min vs seconds)
	If you rotate the solid sample there is much less need to wait.		If you rotate the solid sample there is much less need to wait.
	*** ID10 at the ESRF has a good setup. DCM beam tilting is used instead to avoid moving the sample.		*** ID10 at the ESRF has a good setup. The same for BM26 with a tilted beam setup for solid-liquid interfaces. DCM beam tilting is used instead to avoid moving the sample.
	*** Get inspiration from X-rays to improve the way we measure GISANS		*** Get inspiration from X-rays to improve the way we measure GISANS
	*** Most productive groups are writing their own code and have their own ways to do experiments. Leading groups spend years analysing the data from an experiment. Writing their own code. Sharing is not common.		*** Most productive groups are writing their own code and have their own ways to do experiments. Leading groups spend years analysing the data from an experiment. Writing their own code. Sharing is not common.

/ToF-GISANS

Annikastellhorn — Tue, 07 Apr 2026 07:45:49 GMT

← Older revision		Revision as of 07:45, 7 April 2026
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	These highlights drawn from summary discussion should be edited and extended after more input from breakout group discussion.		These highlights drawn from summary discussion should be edited and extended after more input from breakout group discussion.

			Detailed notes group (?):
			* ToF and mono mode - different data processing requirements. You have a spread of WL, an event mode dataset, whether it is quasi elastically scattered when it arrives on the detector. Mono instrument with no WL recording: making an assumption the signal is elastic. Elastic scattering is predominant but the background its often inelastic.

/Normalization

Annikastellhorn — Tue, 07 Apr 2026 07:45:24 GMT

@@ Line 20: / Line 20: @@
 * What can you get from Q=0 in a GISANS measurement? Can one at all extract a quantitave solution from a GISANS measurement? Should rather we aim at always having proper reference systems that the cross section can be compared with for getting the physical parameters needed?
 ******
 ******

/Multiple Scattering

Apostolos Vagias — Tue, 07 Apr 2026 07:44:45 GMT

← Older revision		Revision as of 07:44, 7 April 2026
(One intermediate revision by the same user not shown)
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	** Diffuse scattering for X-rays at Liq-Liq interface is comparable to neutrons. The beam is below the horizon and there is an attenuated pattern seen.		** Diffuse scattering for X-rays at Liq-Liq interface is comparable to neutrons. The beam is below the horizon and there is an attenuated pattern seen.
	** X-ray Software packages we can take inspiration from? Brookhaven, Ben Ocko, BornAgain		** X-ray Software packages we can take inspiration from? Brookhaven, Ben Ocko, BornAgain

			* Sub-cases of multiple coherent scattering and distinction from incoherent multiple scattering:
			**In the framework of the distorted-wave Born approximation (DWBA), it is essential to distinguish between two distinct processes: (i) the propagation of the incident wave through the stratified medium, which is incorporated _exactly_ in the formalism; and (ii) the scattering from embedded “particles” (additional scattering centers) which is treated perturbatively within the 1st-order Born approximation.
			Both (i) and (ii) are within the quantum theory (‘coherent’). Only in (i), each layer is represented by an effective static potential, simplifying the description of the background medium.

			**The term “multiple scattering” refers to the situation in which successive scattering events are not treated independently but are combined quantum mechanically, i.e., the amplitudes from different scattering paths are added coherently.

			**In contrast, “incoherent multiple scattering” denotes an approximation in which scattering from each center is treated quantum mechanically, but the subsequent propagation of scattered waves is represented within a semi-classical or ray-optical picture (Gaussian optics). This approach is conceptually analogous to the semi-classical treatment of transport phenomena based on the Boltzmann equation, where phase relations between successive scattering events are neglected.

/Common Data Format

Annikastellhorn — Tue, 07 Apr 2026 07:42:42 GMT

← Older revision	Revision as of 07:42, 7 April 2026
Line 1:	Line 1:
		Detailed notes group (?):
		* (repeated in Multiple Scattering Discussion):
		** The package approach in BA might cause issues while SASview does not have them. Once the interface is defined it is hard to change it, same for the file format. One can design them to be extensible (NEXUS), to use new features. One has to think carefully what you insist people provide. For SAS data format, reflection format you need to provide certain information. The idea was that it can be extensible and if information is not provided it is simply skipped.
		*** canSAS XML was developed for this. But people don’t use it in a right way, they don’t fill out the fields, data has incorrect format. It is not easy to solve these problems.
		** The challenge with BA is that we don’t understand what is the input data. Originally was built around a monochromatic instrument with cartesian coordinates around the scattered beam. Strictly speaking SASview works in q space and it doesn’t assume anything about the detector space.
		** One of the differences is how to make the software instrument independent. SASview: you provide reduced data where you have taken out all the instrument effects. The idea of q resolution without WL and angle, it can accommodate data from instruments with multiple detectors, you can concatenate them in one file.
		** Before software for SAS used to compare errors if you have an area detector there are many pixels that goes to the same bin. What is the variation pix to pix in there. Statistics over the individual pixels is compared with the variation. One needs to have more information to test that. When it comes to model fitting you don’t trouble the fitting program with too complicated procedure at the moment. The peak fitting for diffraction already causes people a lot of problems. Once you try to correct for more things you get more uncertainties.
		** With GISANS you re not obliged to throw away the original raw counts. Whether software can handle? The motivation for having a reduced dataset is to have data format that is transferable between softwares. But have you thrown too much at some point?

/Using SANS software

Annikastellhorn — Tue, 07 Apr 2026 07:41:48 GMT

← Older revision		Revision as of 07:41, 7 April 2026
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	* Sample environment should be continuously developed the knowledge is shared inside of the community.		* Sample environment should be continuously developed the knowledge is shared inside of the community.

			Detailed notes group (?):
			* Get inspiration from X-ray software:
			** Brookhaven, Ben Ocko
			* SasView:
			** SASview people can read data in, put different resolution functions, co-fit X-ray and neutron data. For SANS it works but For GISANS not.
			* BornAgain:
			** BornAgain does not have a good defined intermediate format. The challenge is to get it to do fitting rather than simulation. Peaks at the right position is simple, getting right intensities is more complicated. Pictures can look similar but not fit in reality. Fitting in 2D is much harder than fitting in 1D. Few people do it in general. Even reflectivity X-ray and neutron is much more advanced in combined view. But with GISANS it is much more difficult. X-ray industry e.g. XENOCS will sell a GI stage and a software package which will give q xyz components but the fitting will be reduced to cuts (qz at particular q xy) so it is a quasi 1d fitting.
			** Could collaborations like BA benefit from models defined by other software packages? E.g. Is there a form factor for this? Where can we find code for such form factors?
			* Comparison BA and SasView:
			** E.g. the structure of SASview is easy if you want to put a new form factor. Very few people do it. In the last 6 months there have been more people doing that but in general this is one of the problems, you don’t have many people who writes the plugins. What people do more, they combine modules or their own purposes. They are not of great generality, something might be written in a paper and people elaborate the code themselves. One has to learn fro other collaborations.
			Interaction between BA and SASview? ICNS conference. Code camp in Garsching for SASview. No-one from Joachim’s group was participating. There could be something to see how a collaboration works.
			* Regarding data reduction / data formats (repeated there):
			** The package approach in BA might cause issues while SASview does not have them. Once the interface is defined it is hard to change it, same for the file format. One can design them to be extensible (NEXUS), to use new features. One has to think carefully what you insist people provide. For SAS data format, reflection format you need to provide certain information. The idea was that it can be extensible and if information is not provided it is simply skipped.
			*** canSAS XML was developed for this. But people don’t use it in a right way, they don’t fill out the fields, data has incorrect format. It is not easy to solve these problems.
			** The challenge with BA is that we don’t understand what is the input data. Originally was built around a monochromatic instrument with cartesian coordinates around the scattered beam. Strictly speaking SASview works in q space and it doesn’t assume anything about the detector space.
			** One of the differences is how to make the software instrument independent. SASview: you provide reduced data where you have taken out all the instrument effects. The idea of q resolution without WL and angle, it can accommodate data from instruments with multiple detectors, you can concatenate them in one file.
			** Before software for SAS used to compare errors if you have an area detector there are many pixels that goes to the same bin. What is the variation pix to pix in there. Statistics over the individual pixels is compared with the variation. One needs to have more information to test that. When it comes to model fitting you don’t trouble the fitting program with too complicated procedure at the moment. The peak fitting for diffraction already causes people a lot of problems. Once you try to correct for more things you get more uncertainties.
			** With GISANS you re not obliged to throw away the original raw counts. Whether software can handle? The motivation for having a reduced dataset is to have data format that is transferable between softwares. But have you thrown too much at some point?

			* Other:
			** BoToSim and BoToFit.
			** SpinW = software, neutron spinwave. It is Lucas Wilkins’ development in collaboration with another person.

/Multiple Scattering

Annikastellhorn — Tue, 07 Apr 2026 07:31:55 GMT

← Older revision		Revision as of 07:31, 7 April 2026
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	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry		* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry
	** They have to be identified before each experiment		** They have to be identified before each experiment

			Detailed:
			* X-ray comparison (overlapping with topic Background):
			** MS in the end gives extra background
			** Some people use MS to enhance the signal explicitly. Or you make additional layer to enhance reflections
			** Comparing X-ray and neutron background, X-rays behave nicer in terms of MS. When absorption is strong all the scattering is from near the surface. For neutrons the absorption is weak and therefore scattering is of higher intensity.
			** Incoherent scattering cross section for hydrogen is very high and scattering attenuation of the beam penetration is limited. One has to be careful about comparing the theory for X-ray and neutrons.
			** Diffuse scattering for X-rays at Liq-Liq interface is comparable to neutrons. The beam is below the horizon and there is an attenuated pattern seen.
			** X-ray Software packages we can take inspiration from? Brookhaven, Ben Ocko, BornAgain


			* How to measure?
			** GIXOS grazing incidence X-ray offspecular scattering. Scattering from the object is modulated by the reflectivity, you can deduce reflectivity if you estimate the form factor.
			*** When you move a liquid surface and wait for it to stop, the measurement duty cycle is poor (2 min vs seconds)
			If you rotate the solid sample there is much less need to wait.
			*** ID10 at the ESRF has a good setup. DCM beam tilting is used instead to avoid moving the sample.
			*** Get inspiration from X-rays to improve the way we measure GISANS
			*** Most productive groups are writing their own code and have their own ways to do experiments. Leading groups spend years analysing the data from an experiment. Writing their own code. Sharing is not common.

/Background handling

Annikastellhorn — Tue, 07 Apr 2026 07:27:30 GMT

← Older revision		Revision as of 07:27, 7 April 2026
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	* measure multiple states / dispersions / other observables to decrease ratio (unkown parameters)/(measured parameters)		* measure multiple states / dispersions / other observables to decrease ratio (unkown parameters)/(measured parameters)
	* how to judge if the simulation (even if fitting perfectly to the data) is the physical correct one? For the question of which parameters are influencing the cross section mostly using bayesian fitting: see papers from Josh (for reflectometry): https://journals.iucr.org/j/issues/2021/04/00/ge5096/ge5096sup1.pdf		* how to judge if the simulation (even if fitting perfectly to the data) is the physical correct one? For the question of which parameters are influencing the cross section mostly using bayesian fitting: see papers from Josh (for reflectometry): https://journals.iucr.org/j/issues/2021/04/00/ge5096/ge5096sup1.pdf
			* X-ray community:
			** Grazing incidence background subtraction is very difficult already in the X-ray techniques. State of the art for X-ray techniques is looking for areas around the strong peaks. This solution is not optimal. You can’t put down the sample and so the best situation is to do the same experiment at a liquid-liquid interface with motion. Everything is in the same place, you put only the liquids in the same cell, GISAXS image with everything except the molecule which will be placed at the interface. Then make a new sample with the same position of the interface with an added molecule. The background sample has to be as close to the real sample as possible. = To have more information, not to be taken as the recipe for handling background.
			** Surface scattering needs to be known to disentangle it from reflection.
			* ToF aspects:
			** Consider also ToF Background!
			* How to acquire the Background:
			** There is no general way to acquire data, many people do empirical background subtraction because there is no way to calculate it.
			** Cut and put a polynomial under a peak without knowing what the polynomial is supposed to represent.

/GISANS - Advancing data reduction and analysis Workshop

Annikastellhorn — Tue, 07 Apr 2026 06:39:56 GMT

Summary

← Older revision		Revision as of 06:39, 7 April 2026
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	==== Summary ====		==== Summary ====
	* Instrument factors influence measurement strategies and tools are needed to aid this process.		Overall Summary

	* Background - effects of inelastic scattering can change background.		(i) ToF
			* Instrument factors influence measurement strategies and tools are needed to aid this process.
			* Background - effects of inelastic scattering can change background.
			* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.
			* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.
			(ii) Multiple scattering
			* Reflection and refraction should be excluded from multiple scattering
			* Need to agree on a common nomenclature
			* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry
			** They have to be identified before each experiment

	* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.		(iii) Background handling
			* Background subtraction is dependent on:
	* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.		** sample system/geometry/the observable physics.
			* Each system has to be treated in a different way.
	* Reflection and refraction should be excluded from multiple scattering		* A survey will help identifying the necessary / common steps among the community for specific classified systems.
	* Need to agree on a common nomenclature		* In case of multiple scattering: Include McStas as standard for GISANS analysis?
	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry		(iv) Normalization
			* Full quantitative normalization procedure:
	* Background subtraction is dependent on:		** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.
	** sample system/geometry/the observable physics.		* If this is not feasible:
	* Each system has to be treated in a different way.		** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed!
	* A survey will help identifying the necessary / common steps among the community for specific classified systems.		* General aspects (sample independent):
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?		** Precise I(lambda) normalization of the beamlines has to be performed
			(v) Using SANS software
	* Full quantitative normalization procedure:		* Regarding BornAgain:
	** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.		** Need a set of prototype models (check what is on the BA webpage) - especially for inexperienced users
	* If this is not feasible:		** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if overgone.
	** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed!		** Further good features to implement: (i) intensity w.r.t. direct beam, w.r.t multiple scattering background, w.r.t. general expected background (according to experience + commissioning).
	* General aspects (sample independent):		(vi) Instrumentation
	** Precise I(lambda) normalization of the beamlines has to be performed		* Missing
			(vii) Common data format
			* Missing
			* Missing
			(ix) Magnetic Scattering]
			* considering ".nxs" files and dimensions: A scan of everything/motor should be considered a dimension in the "nxs". It should not be restricted to 4 dimensions.
			* On-the-fly polarization analysis: online corrections are good. But highest precision correction should be done at the end of the experiment before the users go home.
			(x) Off-Specular
			* Missing

	==== Outlook ====		==== Outlook ====
	* Letter in "Neutron News"		* Letter in "Neutron News"

/Using SANS software

Annikastellhorn — Tue, 07 Apr 2026 06:30:53 GMT

← Older revision	Revision as of 06:30, 7 April 2026
Line 1:	Line 1:
		Overview:
		* Regarding BornAgain:
		** Need a set of prototype models (check what is on the BA webpage) - especially for inexperienced users
		** This should include a very detailed description about its physical limitations, directly implemented into BA sending error messages if overgone.
		** Further good features to implement: (i) intensity w.r.t. direct beam, w.r.t multiple scattering background, w.r.t. general expected background (according to experience + commissioning).


		Detailed notes group 4:
		* A set of prototype models for several example systems is really great piece of help for inexperienced users of BornAgain.
		* However, it will be even more helpful if every model describes its physical limitations - in other words, a user should be warned if he is choosing a value of a parameter which breaks the validity of the theory behind this model (for example size of the particles, particle distribution over the surface etc). So that a user do not consider unrealistic models.
		* On the top of this it will be nice if a user can estimate
		** intensity of GISANS signal in respect to the direct beam
		** in respect to the multiple scattering background calculated by BornAgain
		** in respect to a general background expected in the experiment (basing on the previous experience with similar sample environment, materials, guide halls etc).

		* Sample environment should be continuously developed the knowledge is shared inside of the community.

/Off-Specular Scattering

Annikastellhorn — Tue, 07 Apr 2026 06:22:32 GMT

Created blank page

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/Notes Data Reduction

Annikastellhorn — Tue, 07 Apr 2026 06:21:15 GMT

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/Computer simulations / AI support

Annikastellhorn — Tue, 07 Apr 2026 06:20:29 GMT

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/GISANS Data Reduction and Analysis Upgrades Initiative

Annikastellhorn — Mon, 06 Apr 2026 13:47:15 GMT

← Older revision		Revision as of 13:47, 6 April 2026
Line 136:		Line 136:
	A first workshop with the international GISA(X/N)S community has been hold in Grenoble on the 17th-18th of March 2026 in hybrid mode. The workshop overview, discussion points, presentation slides, and a summary can be found here:		A first workshop with the international GISA(X/N)S community has been hold in Grenoble on the 17th-18th of March 2026 in hybrid mode. The workshop overview, discussion points, presentation slides, and a summary can be found here:
	[[/GISANS - Advancing data reduction and analysis Workshop #1" 2026-03-17/18]]		[[/GISANS - Advancing data reduction and analysis Workshop #1" 2026-03-17/18]]

	~~[[File:GISANS Programme FINAL.jpg\|thumb\|Workshop programme]]~~
	~~==== Discussion session notes ====~~



	~~'''POINT A. ToF-GISANS'''<br />~~
	* Presentation slides: To come
	* Further Notes from the ILL-Workshop on: [[/ToF-GISANS]]

	~~'''POINT B. Multiple scattering'''<br />~~
	* Presentation slides:
	~~[[File:HF_MuSc GISANS.pdf\|thumb]]~~
	* Further Notes from the ILL-Workshop on: [[/Multiple Scattering]]

	~~'''POINT C. Background handling'''<br />~~
	* Presentation slides:
	~~[[File:Background ideas.pdf\|thumb]]~~
	* Further Notes from the ILL-Workshop on: [[/Background handling]]

	~~'''POINT D. Normalization''' <br />~~
	* Presentation slides:
	~~[[File:GISANS-NormalizationDiscussionStarters.pdf\|thumb\|Introduction to Normalization - Sebastian Jaksch]]~~
	* Further Notes from the ILL-Workshop on: [[/Normalization]]

	~~'''POINT E. Using SANS software''' <br />~~
	* No introduction talk
	* Further Notes from the ILL-Workshop on: [[/Using SANS software]]

	~~'''POINT F / Instrumentation & Q/lambda resolution'''<br />~~
	* Presentation slides:
	~~[[File:2026 03 CANSAS Grenoble Resol Fn JFMoulin.pdf\|thumb\|Introduction to ToF Resolution aspects - Jean-Francois Moulin]]~~
	~~[[File:TopervergGISANS2026ILL1-part1.pdf\|thumb\|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 1]]~~
	~~[[File:TopervergGISANS2026ILL1-part2.pdf\|thumb\|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 2]]~~
	* Further Notes from the ILL-Workshop on: [[/Instrumentation & Q/lambda resolution]]

	~~'''POINT G. Need good documentation'''<br />~~
	* No Introduction talk
	* Further Notes from the ILL-Workshop on: [[/Documentation]]

	~~'''POINT H. Integration of McStas with BornAgain'''<br />~~
	* Presentation slides:
	~~[[File:HF McStas.pdf\|thumb\|Introduction on McStas - Henrich Frielinghaus]]~~
	* Further Notes from the ILL-Workshop on: [[/McStas]]

	~~'''POINT I. Get a common data format for GISANS data reduction:'''<br />~~
	* Presentation slides:
	~~[[File:GISANS 2026 File Formats - Brian Maranville.pdf\|thumb\|Introduction on File Formats - Brian Maranville]]~~
	* Further Notes from the ILL-Workshop on: [[/Common Data Format]]


	~~'''POINT J. Computer simulations / AI support:'''<br />~~
	* No Introduction talk
	* Further Notes from the ILL-Workshop on: [[/Computer simulations / AI support]]

	~~'''POINT K. Off-specular scattering:'''<br />~~
	* Presentation slides:
	~~[[File:Gutfreund OffSpec new part 1.pdf\|thumb\|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 1]]~~
	~~[[File:Gutfreund OffSpec new part 2.pdf\|thumb\|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 2]]~~
	* Further Notes from the ILL-Workshop on: [[/Off-Specular Scattering]]

	~~'''POINT L. Magnetic Scattering:'''<br />~~
	* Presentation slides:
	~~[[File:Magnetic GISANS.pdf\|thumb\|Talk on "Magnetic and PA-GISANS" from Annika Stellhorn]]~~
	* Further Notes from the ILL-Workshop on: [[/Notes Magnetic Scattering]]

	~~'''POINT M. Data Reduction:'''<br />~~
	* Presentation slides:
	~~[[File:2026 03 CANSAS Grenoble Data Reduction TOF JFMoulin.pdf\|thumb\|Introduction to ToF Data Reduction - Jean-Francois Moulin]]~~
	* Further Notes from the ILL-Workshop on: [[/Notes Data Reduction]]

	~~==== Organizational notes ====~~

	~~==== Summary ====~~
	* Instrument factors influence measurement strategies and tools are needed to aid this process.

	* Background - effects of inelastic scattering can change background.

	* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.

	* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.

	* Reflection and refraction should be excluded from multiple scattering
	* Need to agree on a common nomenclature
	* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry

	* Background subtraction is dependent on:
	** sample system/geometry/the observable physics.
	* Each system has to be treated in a different way.
	* A survey will help identifying the necessary / common steps among the community for specific classified systems.
	* In case of multiple scattering: Include McStas as standard for GISANS analysis?

	* Full quantitative normalization procedure:
	** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.
	* If this is not feasible:
	** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed!
	* General aspects (sample independent):
	** Precise I(lambda) normalization of the beamlines has to be performed

	~~==== Outlook ====~~
	* Letter in "Neutron News"

/GISANS - Advancing data reduction and analysis Workshop

Annikastellhorn — Mon, 06 Apr 2026 13:46:59 GMT

Created page with "thumb|Workshop programme ==== Discussion session notes ==== '''POINT A. ToF-GISANS''' * Presentation slides: To come * Further Notes from the ILL-Workshop on: /ToF-GISANS '''POINT B. Multiple scattering''' * Presentation slides: thumb * Further Notes from the ILL-Workshop on: /Multiple Scattering '''POINT C. Background handling''' * Presentation slides: File:Background idea..."

New page

[[File:GISANS Programme FINAL.jpg|thumb|Workshop programme]]
==== Discussion session notes ====

'''POINT A. ToF-GISANS''' 
* Presentation slides: To come
* Further Notes from the ILL-Workshop on: [[/ToF-GISANS]]

'''POINT B. Multiple scattering''' 
* Presentation slides:
[[File:HF_MuSc GISANS.pdf|thumb]]
* Further Notes from the ILL-Workshop on: [[/Multiple Scattering]]

'''POINT C. Background handling''' 
* Presentation slides:
[[File:Background ideas.pdf|thumb]]
* Further Notes from the ILL-Workshop on: [[/Background handling]]

'''POINT D. Normalization''' 
* Presentation slides:
[[File:GISANS-NormalizationDiscussionStarters.pdf|thumb|Introduction to Normalization - Sebastian Jaksch]]
* Further Notes from the ILL-Workshop on: [[/Normalization]]

'''POINT E. Using SANS software''' 
* No introduction talk
* Further Notes from the ILL-Workshop on: [[/Using SANS software]]

'''POINT F / Instrumentation & Q/lambda resolution''' 
* Presentation slides:
[[File:2026 03 CANSAS Grenoble Resol Fn JFMoulin.pdf|thumb|Introduction to ToF Resolution aspects - Jean-Francois Moulin]]
[[File:TopervergGISANS2026ILL1-part1.pdf|thumb|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 1]]
[[File:TopervergGISANS2026ILL1-part2.pdf|thumb|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 2]]
* Further Notes from the ILL-Workshop on: [[/Instrumentation & Q/lambda resolution]]

'''POINT G. Need good documentation''' 
* No Introduction talk
* Further Notes from the ILL-Workshop on: [[/Documentation]]

'''POINT H. Integration of McStas with BornAgain''' 
* Presentation slides:
[[File:HF McStas.pdf|thumb|Introduction on McStas - Henrich Frielinghaus]]
* Further Notes from the ILL-Workshop on: [[/McStas]]

'''POINT I. Get a common data format for GISANS data reduction:''' 
* Presentation slides:
[[File:GISANS 2026 File Formats - Brian Maranville.pdf|thumb|Introduction on File Formats - Brian Maranville]]
* Further Notes from the ILL-Workshop on: [[/Common Data Format]]

'''POINT J. Computer simulations / AI support:''' 
* No Introduction talk
* Further Notes from the ILL-Workshop on: [[/Computer simulations / AI support]]

'''POINT K. Off-specular scattering:''' 
* Presentation slides:
[[File:Gutfreund OffSpec new part 1.pdf|thumb|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 1]]
[[File:Gutfreund OffSpec new part 2.pdf|thumb|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 2]]
* Further Notes from the ILL-Workshop on: [[/Off-Specular Scattering]]

'''POINT L. Magnetic Scattering:''' 
* Presentation slides:
[[File:Magnetic GISANS.pdf|thumb|Talk on "Magnetic and PA-GISANS" from Annika Stellhorn]]
* Further Notes from the ILL-Workshop on: [[/Notes Magnetic Scattering]]

'''POINT M. Data Reduction:''' 
* Presentation slides:
[[File:2026 03 CANSAS Grenoble Data Reduction TOF JFMoulin.pdf|thumb|Introduction to ToF Data Reduction - Jean-Francois Moulin]]
* Further Notes from the ILL-Workshop on: [[/Notes Data Reduction]]

==== Organizational notes ====

==== Summary ====
* Instrument factors influence measurement strategies and tools are needed to aid this process.

* Background - effects of inelastic scattering can change background.

* Resolution is important both as regards wavelength and angle. The latter depends on collimation as well as footprint on the sample and spatial resolution of the detector. Full interpretation of data is likely to require extensive information to be available with processed data.

* Data reduction from raw data will require establishment of appropriate data formats for input to existing modelling and analysis software. The software may also need development to fully exploit the information that is available.

* Reflection and refraction should be excluded from multiple scattering
* Need to agree on a common nomenclature
* There are certain constraints for multiple scattering: mean free path length & coherence length, sample size / curvature / geometry

* Background subtraction is dependent on:
** sample system/geometry/the observable physics.
* Each system has to be treated in a different way.
* A survey will help identifying the necessary / common steps among the community for specific classified systems.
* In case of multiple scattering: Include McStas as standard for GISANS analysis?

* Full quantitative normalization procedure:
** measuring GISANS together with NR & Off-specular scattering, to view the whole Q-space.
* If this is not feasible:
** Same as topic "Background": each system has to be classified for its way "how to be treated" - Survey needed!
* General aspects (sample independent):
** Precise I(lambda) normalization of the beamlines has to be performed

==== Outlook ====
* Letter in "Neutron News"

/GISANS Data Reduction and Analysis Upgrades Initiative

Annikastellhorn — Mon, 06 Apr 2026 13:45:51 GMT

← Older revision		Revision as of 13:45, 6 April 2026
(2 intermediate revisions by the same user not shown)
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	** different backgrounds for different lambda/incident angles which is additionally dominated by multiple scattering		** different backgrounds for different lambda/incident angles which is additionally dominated by multiple scattering
	* Need to differentiate between: (i) incoherent multiple scattering, (ii) multiple scattering for which Born approximation breaks down		* Need to differentiate between: (i) incoherent multiple scattering, (ii) multiple scattering for which Born approximation breaks down
	* Further Notes from the ILL-Workshop on: [[/ToF-GISANS]]
	* Further Notes from the ILL-Workshop on: [[/Multiple Scattering]]

	'''POINT C. Background handling'''<br />		'''POINT C. Background handling'''<br />
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	* Existing user scripts that have proven to work, can be implemented into BA		* Existing user scripts that have proven to work, can be implemented into BA
	* Influence from hydrogen?		* Influence from hydrogen?
	* Further Notes from the ILL-Workshop on: [[/Background handling]]

	'''POINT D. Normalization''' <br />		'''POINT D. Normalization''' <br />
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	* In GISAS, not clear consensus as to how data are reported		* In GISAS, not clear consensus as to how data are reported
	* Correct background substraction and its impact on normalization and absolute intensity calculation has to be taken care of		* Correct background substraction and its impact on normalization and absolute intensity calculation has to be taken care of
	* Further Notes from the ILL-Workshop on: [[/Normalization]]

	'''POINT E. Using SANS software''' <br />		'''POINT E. Using SANS software''' <br />
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	** Needs to be compatible to existing software like GRASP or MANTID		** Needs to be compatible to existing software like GRASP or MANTID
	** Key: well-defined .nxs (canSAS) standard		** Key: well-defined .nxs (canSAS) standard
	* Further Notes from the ILL-Workshop on: [[/Using SANS software]]

	'''POINT F / Instrumentation & Q/lambda resolution (different detector arrays, or, sample geometries-how is data reduced)'''<br />		'''POINT F / Instrumentation & Q/lambda resolution (different detector arrays, or, sample geometries-how is data reduced)'''<br />
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	* To be contributed via “requests”/”patches” to the documentation sources.		* To be contributed via “requests”/”patches” to the documentation sources.
	* Further Notes from the ILL-Workshop on: [[/Documentation]]

	'''POINT H. Integration of McStas with BornAgain'''<br />		'''POINT H. Integration of McStas with BornAgain'''<br />
	* Feedback-loops available (from Artur) between McStas and BornAgain, but no fitting possible		* Feedback-loops available (from Artur) between McStas and BornAgain, but no fitting possible
	* Further Notes from the ILL-Workshop on: [[/McStas]]

	'''POINT I. Get a common data format for GISANS data reduction:'''<br />		'''POINT I. Get a common data format for GISANS data reduction:'''<br />
	* Making use of canSAS and ORSO standards		* Making use of canSAS and ORSO standards
	* Need to extend both the canSAS/ORSO formats towards GISAS		* Need to extend both the canSAS/ORSO formats towards GISAS
	* Further Notes from the ILL-Workshop on: [[/Common Data Format]]


	~~'''POINT J. Computer simulations / AI support:'''<br />~~

	* Further Notes from the ILL-Workshop on: [[/Computer simulations / AI support]]

	~~'''POINT K. Off-specular scattering:'''<br />~~

	* Further Notes from the ILL-Workshop on: [[/Off-Specular Scattering]]

	~~'''POINT L. Magnetic Scattering:'''<br />~~

	* Further Notes from the ILL-Workshop on: [[/Notes Magnetic Scattering]]

	~~'''POINT M. Data Reduction:'''<br />~~

	* Further Notes from the ILL-Workshop on: [[/Notes Data Reduction]]

	====“How-to”====		====“How-to”====
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	=== First workshop at ILL, France: "GISANS - Advancing data reduction and analysis" 2026-03-17/18 ===		=== First workshop at ILL, France: "GISANS - Advancing data reduction and analysis" 2026-03-17/18 ===

			A first workshop with the international GISA(X/N)S community has been hold in Grenoble on the 17th-18th of March 2026 in hybrid mode. The workshop overview, discussion points, presentation slides, and a summary can be found here:
			[[/GISANS - Advancing data reduction and analysis Workshop #1" 2026-03-17/18]]

	[[File:GISANS Programme FINAL.jpg\|thumb\|Workshop programme]]		[[File:GISANS Programme FINAL.jpg\|thumb\|Workshop programme]]
	==== Discussion session notes ====		==== Discussion session notes ====



	'''POINT A. ToF-GISANS'''<br />		'''POINT A. ToF-GISANS'''<br />
	* Presentation slides:		* Presentation slides: To come
	* Further Notes from the ILL-Workshop on: [[/ToF-GISANS]]		* Further Notes from the ILL-Workshop on: [[/ToF-GISANS]]

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	* Presentation slides:		* Presentation slides:
	[[File:2026 03 CANSAS Grenoble Resol Fn JFMoulin.pdf\|thumb\|Introduction to ToF Resolution aspects - Jean-Francois Moulin]]		[[File:2026 03 CANSAS Grenoble Resol Fn JFMoulin.pdf\|thumb\|Introduction to ToF Resolution aspects - Jean-Francois Moulin]]
	* Add slides from Boris Toperverg: ~~check what to do when file too big~~		[[File:TopervergGISANS2026ILL1-part1.pdf\|thumb\|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 1]]
			[[File:TopervergGISANS2026ILL1-part2.pdf\|thumb\|Talk "DWBA: kinematics, coherence & resolution issues" from Boris Toperverg - Part 2]]
	* Further Notes from the ILL-Workshop on: [[/Instrumentation & Q/lambda resolution]]		* Further Notes from the ILL-Workshop on: [[/Instrumentation & Q/lambda resolution]]

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	'''POINT K. Off-specular scattering:'''<br />		'''POINT K. Off-specular scattering:'''<br />
	* Presentation slides:		* Presentation slides:
			[[File:Gutfreund OffSpec new part 1.pdf\|thumb\|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 1]]
			[[File:Gutfreund OffSpec new part 2.pdf\|thumb\|Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 2]]
	* Further Notes from the ILL-Workshop on: [[/Off-Specular Scattering]]		* Further Notes from the ILL-Workshop on: [[/Off-Specular Scattering]]

	'''POINT L. Magnetic Scattering:'''<br />		'''POINT L. Magnetic Scattering:'''<br />
	* Presentation slides:		* Presentation slides:
			[[File:Magnetic GISANS.pdf\|thumb\|Talk on "Magnetic and PA-GISANS" from Annika Stellhorn]]
	* Further Notes from the ILL-Workshop on: [[/Notes Magnetic Scattering]]		* Further Notes from the ILL-Workshop on: [[/Notes Magnetic Scattering]]

File:Magnetic GISANS.pdf

Annikastellhorn — Mon, 06 Apr 2026 13:38:05 GMT

Annikastellhorn uploaded File:Magnetic GISANS.pdf

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Talk on "Magnetic and PA-GISANS" from Annika Stellhorn

File:Gutfreund OffSpec new part 2.pdf

Annikastellhorn — Mon, 06 Apr 2026 13:36:12 GMT

Annikastellhorn uploaded File:Gutfreund OffSpec new part 2.pdf

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Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 2

File:Gutfreund OffSpec new part 1.pdf

Annikastellhorn — Mon, 06 Apr 2026 13:35:50 GMT

Annikastellhorn uploaded File:Gutfreund OffSpec new part 1.pdf

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Talk on "Offspecular Scattering" from Philipp Gutfreund - Part 1

← Older revision		Revision as of 11:34, 20 April 2026
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	=== Latest News ===		=== Latest News ===
			2026-03:<br />
			'''GISANS Data Reduction and Analysis'''<br />
			A workshop was held in Grenoble to discuss GISANS data reduction and analysis. Summary note are available:

			https://wiki.cansas.org/index.php?title=/GISANS_-_Advancing_data_reduction_and_analysis_Workshop

	2025-11:<br />		2025-11:<br />