150 likes | 305 Views
Collimator Studies. z location revisited new field map preliminary tilt studies some target boiling results. collimator z-location. back in January we were discussing the collimator design and the backgrounds Roger suggested trying to make the lower edge of the collimator defined
E N D
Collimator Studies • z location revisited • new field map • preliminary tilt studies • some target boiling results
collimator z-location back in January we were discussing the collimator design and the backgrounds Roger suggested trying to make the lower edge of the collimator defined in the most upstream collimator this would help eliminate the lower edge of the “VT row 20” acceptance defining collimator as a large source of background turns out that the hit we take because of finite target effects is just too big
collimator z-location “VT row 20” try to define lower edge upstream
new field map in April, Jim posted a new field map produced by Peiqing Wang and Willie Falk the map was based on the “as manufactured” coils, which means that it is not identical in all octants Jim had tested the map and noticed that the focus wasn’t as good as with the old map, but it still fit on the bar as I began testing my implementation of the new map, I discovered some problems with the read-in code having to do with the arrays should be okay now! Compare Q2 distributions for old map (black), new map (red), BFIL 1.00
new field map “VT row 20” with BFIL 1.00 “25cm upstream” with BFIL 1.00
new map comparisons New map, BFIL 1.04. Old map, BFIL 1.00. New map, BFIL 1.00. Blue – Elastic electrons Red – Inelastic Electrons
collimator tilt studies removed “cleanup” collimators no beamline, new map BFIL 1.00 did not move the quartz bar (lower edge 315cm) for pitch, roll and yaw ±5º for x, z ±5 cm Also assumed all plots were linear, though some obviously aren’t
Qweak beam tests • performed March 26th , 27th • target boiling studies • low current tests (see Mark’s talk) • beam current monitoring (Dave Mack) Thanks to everyone who took shifts!
target boiling studies 30 Hz, 8Hz fan, 1.2x1.2 raster, C 30 Hz, 8Hz fan, 1.2x1.2 raster, C 250 Hz, 8Hz fan, 1.2x1.2 raster, C 250 Hz, 8Hz fan, 1.2x1.2 raster, C