A Method to Measure the Flatness of the LSST Focal Plane Assembly in Situ

Langeveld, Willy

Stanford Linear Accelerator Center

关键词: Measuring Methods;    Cryostats;    Other,Other;    Accuracy;    Accelerator Facilities Other,Other;   

DOI  :  10.2172/878027
RP-ID  :  SLAC-TN-05-047
RP-ID  :  AC02-76SF00515
RP-ID  :  878027

美国|英语

来源: UNT Digital Library

【 摘 要 】

In this note I describe an inexpensive and simple laser-based method to measure the flatness of the LSST focal plane assembly (FPA) in situ, i.e. while the FPA is inside its cryostat, at -100 C and under vacuum. The method may also allow measurement of the distance of the FPA to lens L3, and may be sensitive enough to measure gravity- and pressure-induced deformations of L3 as well. The accuracy of the method shows promise to be better than 1 micron.