round robin

Q Standard Round Robin

This page is the working page for the Q Standard round robin.

Members

• Joseph Kline (NIST - chair)
• Caitlyn Wolf (NIST)
• Adrian Rennie (Uppsala University)
• Paul Butler (NIST - temporary?)
• Others TBA

Round robin consists of a tungsten grating calibration sample and three "unknown" block copolymer samples with different characteristic length scales. The round robin is blinded so that participants do not know the exact pitch of the tungsten grating calibration sample. The round robin will test current calibration methods used by beamlines and the improvement of calibration obtained by using the new calibration sample.

Round Robin Process

• Sample set consisting of tungsten grating calibration sample and three "unknown" block copolymers
  • Five similar sample sets will travel between facilities. Each set is slightly different, but pitches are known by NIST
• Participants will receive a sample set, conduct their normal calibration measurement, measure the tungsten grating sample like they would measure a calibration sample, then measure the unknown block copolymer samples
• Participants will report their results and estimated values of grating pitch and block copolymer length scales using their normal calibration
• Sample set will be returned to NIST and then sent to next participant
• NIST will compile results and send participants the pitch of the grating sample that they measured to recalibrate their measurements
• Final results will be combined into a publication

Round Robin Details

• 34 SAXS beamlines have responded to invitation to participate in the round robin
• First sample sets were shipped out on June 4, 2026 with goal of completing the round robin measurements in the calendar year 2026
• If interested in participating in the round robin, please contact saxs@nist.gov
• The current calibration sample is optimized for SAXS. An additional calibration sample is being developed with much large area pattern for neutron scattering