(GRINCH) Detector for BigBite - Hall A

Gas Ring Imaging Cherenkov (GRINCH) Detector for BigBite Abdellah Ahmidouch and Samuel Danagoulian Department of Physics NC A&T State University, Greensboro, NC Todd AvereT, H. Yao, William and Mary B. Wojtsekhowski, S. Esp, Jefferson Lab K. Aniol, Cal. State LA J. Annand, Glasgow 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 1 Outline •  MoHvaHon •  Design •  Status •  Status of the mirrors •  Status of the detecHon array •  Prototype measurements •  Time scale •  BudgeHng •  Summary 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 2 MoHvaHon: High Rate Running •  Expect 4‐5x increase in total luminosity over previous BigBite running. •  Assume 4‐5x background rate. •  30 degree scaTering angle •  Segmented PMT array (29mm tubes), 9(8) x 60 tubes •  Search for Hming clusters in 5‐10 ns window. •  MagneHc shielding between rows. •  Locate PMT array on large angle side away from beam line. •  C4F8O heavy gas at 1 atm 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 3 SimulaHon and Design •  Design based on GEANT 4 simulaHon (W&M) and geometric constraints from BigBite detector package •  65 cm path length, 85 cm reflected path •  Single reflecHon from cylindrical mirrors. Not focusing on specific PMT’s, not sensiHve to precise mirror geometry/alignment •  Clusters with avg 10 PMT’s/event and 1.7 p.e.’s/tube 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 4 Design Update •  First version of design complete. •  Approval granted to complete full producHon drawings to solicit bids. Expected June 2013. •  Detector vessel made from frame of angled aluminum with sheet aluminum sides (Jlab) •  9 (8) x 60 array of PMT’s in iron box, with mu metal and iron strips/bars between rows. ATach to vessel, removable. (NC A&T) •  Removable mirror frame, adjustable mirror mounHng system. (W&M) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 5 Design 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 6 Mirror Frame 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 7 Mirror alignment tests •  We expect to coat flat 1/8” thick Lexan and then bend into the correct shape by applying torque with the mounHng hardware. •  Second opHon, pre‐formed mirror blanks that would then be coated (thicker with backing and more expensive). •  JLab design group and W&M machine shop produced a full size prototype of the mirror mounHng system. •  We are currently measuring the geometry of a 1/8” Lexan sheet and learning how to produce a cylindrical surface. Cost esHmate to make full mirror frame and mounts at W&M is about $5k. 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 8 Mirror alignment tests (cont.) Results to date: •  FuncHonality of mount and adjustment is good. •  Radius of curvature is not naturally constant across the width of the mirror. Not unexpected. Nonlinear. •  Learning to mechanically shape mirror to give proper transport of light to locaHon of PMT array. •  Con‐currently developing laser alignment system. 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 Mirror 9 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 10 Mirror ReflecHvity Tests •  Received sample of Al‐coated Lexan, flat pieces, from ECI coaHngs. •  H. Yao measured reflecHvity in test stand in FEL building. Manufacturer data 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 11 ReflecHvity Results •  Results not clean because: •  System designed for mirrors that focus all reflected light onto a photodiode. •  Doesn’t work geometrically for flat mirror. Realignment of PD required during scans. •  SHll, reflecHvity generally above about 86% 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 12 ConHnued Mirror Tests •  We measured the relaHve reflecHvity raHo at 3 fixed wavelengths in the visible spectrum for a sample mirror that was first flat and then bent to the proper cylindrical radius. This was repeated several Hmes and no change in reflecHvity within our precision (est. 10% rel.) was observed. Successful formed Lexan using custom made heated molds. Not opHcal quality. •  Successfully slumped and glued a 1’ x 1’ prototype mirror with honeycomb and Lexan backing (similar to Hall A HRS design). Not opHcal quality but proof of principle to form the correct mirror geometry if needed prior to coaHng. See next slide 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 13 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 14 Front end Electronics •  J. Annand has produced phase II prototype of NINO front‐end card. •  Successfully tested phase I card using signals similar to expected small‐amplitude single PE signals from GRINCH. •  K. Aniol recently completed purchase for all NINO cards. 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 15 Plans (W&M) •  Finish producHon drawings for vessel, mirror mounHng, July 31st, 2013 –  Send drawings for quotes –  FabricaHon, Fall 2013 (need Jlab approval) –  Assembly, tesHng, Early 2014 •  Finalize mirror design studies by May 30th –  Order mirrors in summer. •  Other summer projects – 
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6/4/13 Gas system Mirror alignment system Cables Gain matching studies using rates/Hming (with NC A&T) HV distribuHon system (with NC A&T) SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 16 Photon Detector Array (NC A&T)   Array of 9(8)x60 29‐mm PMTs ET: 29 mm photomulHplier 9125B from DIRC   Housed in an iron magneHc shielding box. Steel 1008   Each row is shielded at the front by two adj. 1‐mm thick plates (µ‐metal and iron)   Mirrored plasHc cones for light collecHon (light catchers) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 17 Photon Detector Array (cont.) Prototype parts: a) magneHc shielding box b) 1 mm steel bars, made of steel‐1008 c) µ‐metal shielding box d) Light catchers Prototype: 4 rows of 9(8) PMTs + reflectors + Mag. Shield box  Assembled and tested  the reflectors and 1 mm steel bars will be sent for mirror deposiHon. 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 18 Detector Array status •  Prototyping done (pending mirror deposiHon) •  PDA final design July ‐ September 2013 (JLAB designer) •  PDA fabricaHon September‐November 2013 •  PDA Assembly December 2013 – January 2014 •  Test of the PDA January – March 2014 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 19 Photon Detector Array. Prototyping 1. Light catcher 2. µ‐metal box 3. Prototype box with 1 mm bars. 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 20 Photon Detector Array Prototyping (cont.) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 21 Photon Detector Array Prototyping (cont.) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 22 Prototype TesHng ConfiguraHon a,b,c 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 23 Prototype TesHng •  Results of magneHc test at A&T Configura)on Bx,y,z w/o shielding box Bx,y,z at the ph‐
cathode (with shielding box) Comments a (plates are along XZ) Bx0= 0 By0 = 0 Bz0 = 15 G Bx= 0 By = 0 Bz = 3.5 G (±0.2) b Bx0= 15 G By0 = 0 Bz0 =0 Bx= 0 By = 1.6 G Bz = 0 c (field is along Y) Bx0 = 0 By0= 15 Bz0= 0 Bx= 0 By = 0 Bz = 0 6/4/13 z
x SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 y
24 Prototype TesHng (cont.) •  Results of magneHc test at W&M Configura)on Bx,y,z w/o Bx,y,z at the ph‐
shielding box cathode (with shielding box) Comments z y x a (plates are along XZ) Bx0= 0 By0 = 0 Bz0 =30.5 G Bx= 0.4 By = 0.9 Bz = 7 G c (plates are along XY) Bx0= 0 By0 = 0 Bz0 = 30.5 G Bx= 2.0 G
By = 0 Bz = 1.2 G 6/4/13 (±0.2) SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 25 Prototype TesHng (cont.) The efficiency of the PMT decreases to 90% if the field strength in Z direcHon is kept within ±7 G. In X direcHon (perpendicular to dynodes) the tolerance is ±4 G, in Y direcHon ‐ ±1.5 G 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 26 Budget (A&T) •  PMT detector array: •  MagneHc Shielding Box, Steel 1008 ~
$6000.00 •  Mu‐metal shelf ~$1000.00 •  Light catchers. Molding is done (~$10,000.00). Each row is $3, we need 60 rows. •  Mirror deposiHon: ? 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 27 Summary •  The Gas Cherenkov (GRINCH) will be completed and tested by Spring 2014 and ready to install by June 2014 –  Vessel, mirror mounHng system, mirrors (JLAB, W&M) –  Photon Detector Array (NC A&T) –  Front electronics (Cal. State LA, Glasgow) •  Total Budget: ~$25 K (NCA&T) ~$50 K (W&M), $10 K (Glasgow University), $50 K (JLAB) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 28 Summary (cont.) 6/4/13 SBS CollaboraHon MeeHng. JLAB, June 4‐5, 2013 29