XRT E2E Test

Day 20050607 Shift B

Test Conductor E. DeLuca

Shift Scientists M. Weber & J. Scott

Section 7 of the XRT E2E Procedure is determining the FOV Optimized Focus Position (OF, or FOVOF). In Section 6 (Best Focus II), the BF position was determined: BF = -850 focus-steps = -515 um. Specifying that OF is located where the optic PSF has twice the width as at BF, we estimated this location to be: OF = -1462 focus-steps = -798 um.

The off-axis response was surveyed at several focus positions in the vicinity of the estimated OF. At each focus position, two or three 1D pitch/yaw scans were made at different angles. We wish to maximize the image area where the point-source width is less than 2.02 pixels. This threshold is indicated in the following plots.

It appears (from the plots below) that image performance is improved by moving to focus positions more positive than was expected. It is not clear at this point that we have actually bracketed the BF or OF positions!

Position 1: -1259 fsteps = -715 um

Position 2: -1509 fsteps = -815 um

Position 3: -1044 fsteps = -615 um

Position 4 (BF): -850 fsteps = -515 um