Focal Plane Scanner Jeff Martin University of Winnipeg

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Focal Plane Scanner Jeff Martin University of Winnipeg with: Jie Pan, Peiqing Wang, David

Focal Plane Scanner Jeff Martin University of Winnipeg with: Jie Pan, Peiqing Wang, David Harrison

Motivation • Q 2 determination, background studies, all done at 10 n. A using

Motivation • Q 2 determination, background studies, all done at 10 n. A using tracking system. • Region III operable up to 100 n. A. • Qweak production running 180 A. • Need a way to extrapolate over 3 orders of magnitude.

Qweak Focal Plane Scanner • A scanning detector with small active area to sense

Qweak Focal Plane Scanner • A scanning detector with small active area to sense high-energy electrons, operable at any beam current. • Similar technique used in E 158 and HAPPEx. • For E 158, it was used to determine optics parameters, confirm Monte Carlo predictions of rates.

Scanner Principle pre-rad quartz radiator Č scattered electrons air-core light pipe PMT Design criteria:

Scanner Principle pre-rad quartz radiator Č scattered electrons air-core light pipe PMT Design criteria: • 1 cm 2 active area. • 1 MHz max rate allows operation in counting mode with two PMT’s. • operable at both high and low current.

Scanner Concept scattered electrons side view beam view

Scanner Concept scattered electrons side view beam view

Implementation in Qweak x-axis motion • • y-axis motion Č-bar 2 D motion assy

Implementation in Qweak x-axis motion • • y-axis motion Č-bar 2 D motion assy scans behind Č-bar Mount in any one octant at a time Attach to fixed support structure Motion assy mounted “inside” Č-bars

Recent Progress on Scanner • 3/06 – Approval from CFI received (detector lab) •

Recent Progress on Scanner • 3/06 – Approval from CFI received (detector lab) • 4/06 – Funding from NSERC received (scanner) • Report for today: – Start of prototyping tests related to detector performance. – Simulation of detector performance. – Mechanical design • Mounting and 2 D motion assy. • Detector assy.

Prototyping Tests (Pan, Wang, Harrison) • 2” tube lined with “Alzak” sheet (aluminum sheet

Prototyping Tests (Pan, Wang, Harrison) • 2” tube lined with “Alzak” sheet (aluminum sheet with PVD aluminum on top, and clear anodized) “Anomet” “MIRO 2”

Prototyping Tests – Cosmics Testing upper trigger test detector lower trigger inside Alzak tube

Prototyping Tests – Cosmics Testing upper trigger test detector lower trigger inside Alzak tube is a small test scint mounted on a plunger

Prototyping Tests • MCA reads out shaped pulse height. • Begun work with small

Prototyping Tests • MCA reads out shaped pulse height. • Begun work with small scintillator samples. (Plan to transition to quartz) • Begun work with high reflectivity light pipes. • Electronics to be replaced with CFI funded detector lab.

Simulation • Builds on Qweak. Sim (K. Grimm, M. Gericke) • Currently at stage

Simulation • Builds on Qweak. Sim (K. Grimm, M. Gericke) • Currently at stage of benchmarking vs. E 158 NIM article.

Simulation – comparisons to E 158 NIM E 158 Jie Pan • work in

Simulation – comparisons to E 158 NIM E 158 Jie Pan • work in progress • q. e. model not right, etc. different prerad

Mechanics • support structure (P. Medeiros, G. Smith) • 2 D motion assy. •

Mechanics • support structure (P. Medeiros, G. Smith) • 2 D motion assy. • detector assy. (P. Wang and G. Mollard @ UM)

Mechanics • support structure – early 2006, decision to not use R 3 rotator

Mechanics • support structure – early 2006, decision to not use R 3 rotator – plan now is to mount to fixed Cherenkov-bar support structure, most of device in towards beamline. – motion octant-to-octant possible by bolting device in place – need drawings! • 2 D motion assy. – budgetary quote from Bosch-Rexroth. – no progress other than some discussions with P. Decowski (E 158 scanner) on rad hardness.

Mechanics • detector assy. – initial 2 D CAD drawings – begun 3 D

Mechanics • detector assy. – initial 2 D CAD drawings – begun 3 D Solid. Works model (P. Wang) – eventually, support from UM shop (G. Mollard) starting on Solid. Works design

Summary and to-do list • Answer prototyping/simulation questions: – – radiator design (quartz? scint?

Summary and to-do list • Answer prototyping/simulation questions: – – radiator design (quartz? scint? size? tilt angle? prerad? ) tube diameter (backgrounds) two-tube layout (backgrounds and fiducial area) establish viability of coincidence technique (rates) • Mechanics – support structure – need P. Medeiros’ time. – purchase 2 D motion assy. and program it. – design and build a mechanical mock-up of detector assy and then a realistic detector

Additional Uses of a Scanner Detector • Scan over large fiducial region, into inelastic

Additional Uses of a Scanner Detector • Scan over large fiducial region, into inelastic region, over Cherenkov bar light guides, to get additional confidence in backgrounds. • “Light map” can be compared to simulation. • Q 2 extrapolation/determination – mini-torus setting during production running? – gas vs. liquid target extrapolation? – at least, complementary to region III.

Implementation in Qweak x-axis motion y-axis motion Č-bar • 2 D motion assy scans

Implementation in Qweak x-axis motion y-axis motion Č-bar • 2 D motion assy scans behind the Č-bar • Mount in one octant, attach to fixed support structure

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

Implementation in Qweak

 • Expected rates at 180 A • Max rate = 1 MHz courtesy

• Expected rates at 180 A • Max rate = 1 MHz courtesy J. Mammei

Procedure • Measure light distribution with scanner at low beam current acceptable to region

Procedure • Measure light distribution with scanner at low beam current acceptable to region III and Cherenkov bar coincidence. • Measure light distribution with scanner at 180 u. A. • If they are the same, region III/Cherenkov light distribution believable at 180 u. A to high confidence. – Note: scanner light map will not be the same as the region III/Cherenkov bar coincidence map.