RPCs for the W measurement in PHENIX Chong Kim Korea University Japan-Korea PHENIX collaboration workshop, Nov. 27, 2012 for the PHENIX collaboration

Outline 1.PHENIX RPCs 2.Ongoing activities and Preparations for Run 13 3.Summary 2/24

3/24 RPC 3 MuTRG RPC 1 35 cm thick SS310 absorber PHENIX forward muon trigger upgrade for W program SS310 (Stainless Steel) absorber: reduce low-p hadron’s punch through MuTRG: fast determination of high momentum tracks (tracking) RPCs: provide timing information and rough position information (timing + tracking) 1. PHENIX RPCs

4/24 PHENIX muon trigger RPC Bakelite double gap RPC Based on CMS endcap RPC technology and expertise Fast time response: 1 ~ 2 ns for MIP Gas mixture: - 95 % C 2 H 2 F 4 (R134A, base gas for avalanche mode RPC) % i-C 4 H 10 (isobutane, photon quencher) % SF 6 (electron quencher) - ~ 40 % relative humidity Cu foil (2 mm) Mylar sheet Module frame (Al) PHENIX RPC requirements  Most conditions are same to those for the CMS endcap RPCs Time resolution≤ 3 ns Average cluster size≤ 2 strips Efficiency ＞ 95 % Rate capability0.5 kHz/cm 2 Average noise rate ＜ 10 Hz/cm 2 # of streamer mode ＜ 10 % 1. PHENIX RPCs

5/24 Station 3 (16 half octants) A half octant (3 RPC modules) RPC3 Module C Module B Module A 2.05 m 4.93 m 0.54 m RPC station 3 One side (N or S) of RPC station 3 is composed of 16 half octants An half octant is composed of 3 RPC modules (type A, B, and C) Each module is a double-gap RPC which satisfies PHENIX requirements RPC 3 1. PHENIX RPCs

6/24 Module assembly flow Lay down a Mylar sheet & Cu foil on the bottom module frame Put lower gap & Attach service lines (H.V, gas) Prepare readout strips & Place it on the lower gap Put upper gap on the strip & Attach service lines Put a Mylar sheet on upper gap & Wrap the cu foil Close module frame Production of a module for Station 3 Fully assembled RPC detector module Before wrap the Cu foil Connect CPE cable to the H.V cable (upper gap) Connect gas tubes to the upper gap Put upper gap on the readout stripPut readout strip on the lower gapPreparing readout strip (attach signal cables)Connect CPE cable to H.V cable on the bottom RPC gapConnected gas tubePlace lower gap into Cu foil & Connect Polyethylene gas tubesLay down Cu foil on the Mylar sheet (+ frame) Assembly of module C 1. PHENIX RPCs

7/24 Module QA Before assembly (Gap QA) Spacer pop check Gas leakage check HV hold Dark current After assembly (module QA) Noise rate check Cosmic ray test QA (Quality Assurance) for a detector module: Before assembly: spacer condition, gas leakage, HV hold and dark current After assembly (test by cosmic muons): noise rate, total & strip efficiency, time resolution & cluster size RPC cosmic ray test stand - event display cosmic ray trigger scintillators RPC readout strip planes cosmic ray trajectory 1. PHENIX RPCs

8/24 Noise rate: RPC HV = 9.5 kV, PHENIX RPC FEE threshold = 160 mV Noise rate (Hz/cm 2 ) Raw TDC : 1 unit = 100 ns/44 = 2.41 ns Time resolution vs. HV Efficiency of a module (%) vs. HV with different thresholds Cluster size of a module vs. HV with different thresholds Operation voltage PHENIX requirements Module QA results 1. PHENIX RPCs

9/24 Integrated result of half-octants QA AT FACTORY Average noise rate: 0.37 Hz/cm 2 ↔ PHENIX requirement: ＜ 10 Hz/cm 2 1. PHENIX RPCs

10/24 Integrated result of half-octants QA AT FACTORY RPC3 S Average noise rate: 0.25 Hz/cm 2 ↔ PHENIX requirement: ＜ 10 Hz/cm 2 1. PHENIX RPCs

11/24 RPC3N - installation (Nov. 11 th, 2009)RPC3S - installation (Sep. 22 nd, 2010) Full integration to the PHENIX DAQ system was completed during Run PHENIX RPCs

12/24 RPC1 90 cm 67 cm Octant 34 cm RPC station 1 Composed of 16 octants for both sides (8 octants for one side) Each octant is a double-gap RPC Two types of octants (A1, A2) for one side: geometrical condition was considered RPC 1 1. PHENIX RPCs

13/24 1. PHENIX RPCs

14/24 RPC1N - installation (Sep. 22 nd, 2011) RPC1S - installation (Dec. 07 th, 2011) 1. PHENIX RPCs

15/24 3D Event display Relative efficiency measurement (St 3 and St 1): ε = # of hits on RPC / # of projected μ track on RPC Hitmap of MuTR and RPC3 (Matched to RPC3 geometry) Muon Track Associated hits Raw hits Timing distributions of RPC3 2. Ongoing activities and Preparations for Run 13

16/24 Improvement in efficiency calculating method is underway Both RPC3 and RPC1 efficiency study is ongoing Efficiency vs. Half OctantsEfficiency vs. Positions Run (pp200GeV, official) : example of ongoing efficiency study, p > 3 GeV (NOT final: contains a lot of fakes!) 2. Ongoing activities and Preparations for Run 13

17/24 Efficiency vs. Run by Module type, for all pp 200 GeV Runs (NOT final!) 2. Ongoing activities and Preparations for Run 13

18/24 Absolute efficiency measurement by using Hodoscope (St 3) RPC3 MuID MuTR ! LocationDesign of Hodoscope D. Jumper (UIUC) 2. Ongoing activities and Preparations for Run 13 Efficiency by Hodoscope (NOT final)

19/24 M. Sarsour (GSU) 2. Ongoing activities and Preparations for Run 13 St 1 efficiency measurement by using cosmic muons RPC1 MuTR St 1 Track extrapolated from MuTR St 1 to RPC1 (NOT final)

20/24 M. Leitgab (UIUC) and PHENIX thechs 2. Ongoing activities and Preparations for Run 13 Additional shielding plan 1)Shielding lower Half-Octants vs. backsplashes from DX magnet By using 144 steel bricks, each 5.1×10.2× kg (300 total ordered) Stacked in 7.6 (cm) high, 40.7 wide, 3 rows Gives layer of steel in 61.0 (cm, in z) × 15.2 thick × (x) Fill any additional spaces with spares/scrap steel Figure made by R. Seidl, used by M. Leitgab, and quote by C.Kim Plots made by Ralf Seidl, used by M. Leitgab, quoted by C. Kim Figure by D. Lynch

21/24 2. Ongoing activities and Preparations for Run 13 M. Leitgab (UIUC) and PHENIX techs Additional shielding plan

22/24 F. Giordano, D. Jumper (UIUC) and PHENIX techs 2. Ongoing activities and Preparations for Run 13 RPC1 temperature control Temperature control: Very little space remains when Muon arms are in Run position Install thermocouples (2 per side) for monitoring Install blowers (2 per side) to increase air flow Thermocouple calibration and Blower installation is underway

23/24 2. Ongoing activities and Preparations for Run 13 F. Giordano, D. Jumper (UIUC) and PHENIX techs Gas recirculation Former gas circulation method suspected makes impurities in flowing gas Performed all 3 test by using 2 spare RPC1 octants for 2 weeks: no effect Case 1 test ongoing by using prototype RPC1 without linseed oil coating Preparing for check gas itself by using gas analyzer Case 1Case 2Case 3

24/24 PHENIX RPCs for the forward muon trigger system Provides timing and additional position information All of stations were produced, tested, and installed Ongoing activities and Preperations: Efficiency measurement for both stations by using real data and cosmic muons… Additional shielding, temperature control, gas recirculation tests, timing shift control, dead/hot channels management, put ‘watchdog’ process in MuTrig for misalignment in several RPC1… Not an ideal we-are-ready-to-go state, but we’re closing to it step by step 3. Summary

Thanks!

Backup B/1 Spin crisis: DIS result at 1980s: proton spin is not a simple sum of its constituent quarks Component-by-component approach: quarks/antiquarks, gluons, and their angular momenta → ½ = ½ΔΣ + ΔG + L z W measurement at PHENIX: Full flavor separation of quarks/antiquarks Measure the polarization of the quark by leptons decayed from W boson A L W : single spin asymmetry p: beam polarization (Max. 70 % for 500 GeV pp) N L(R) (W) : # of events contains the muons from W with corresponding helicity (L or R) ΔΣ = ± for Q 2 = 10 and ≤ x ≤ 1

Backup B/2 PHENIX Run 12 - pp 510 GeV remark Statistics: more than 30 pb -1 for vtx ≤ 30 cm Beam polarizability: larger than 60 % Newly integrated detectors: RPC1 and FVTX

Backup B/3 Muon Hadron Muon Tracker (MuTr) Muon ID (MuID) PHENIX muon arms (before upgrade) Acceptance < |η| < Δφ = 2π Muon Tracker (MuTR) - 3 stations of CSCs Muon ID (MuID) - 5 gaps of larocci tube in x & y directions - Total 80 cm thick steel absorber (plates) Muon tracking and triggering - Tracking by hit positions from each station - Most hadrons are absorbed before reaching last gap of the MuID - Current 1 st level rejection factor (RF): ~ 100 (MuID based 1 st level trigger)

Backup B/4 Simulated muons into Muon Arms (2000 pb -1, with PYTHIA 5.7) MuID base trigger (before trigger upgrade) W measurement at PHENIX muon arms √s = 500 GeV σ = 60 mb L = 1.5 x cm -2 s -1 → 3.0 x cm -2 s -1 (after luminosity upgrade) Total interaction rate: 9 MHz DAQ limit: 2 kHz Required 1 st level rejection factor (RF): 4500 Dedicated trigger system is required: → Forward muon trigger upgrade After trigger upgrade

Backup Momentum selectivity through online sagitta measurement Uses MuTr station 1, 2, 3 and RPC station 1, 3 Implement trigger using fast, parallel logic on FPGA’s Beam related background rejected by RPC’s timing information RPC 1 RPC 3 B/5

Backup MuTRG ADTX MuTRG MRG Level 1 Trigger Board MuTr FEE Resistive Plate Chamber (RPC) (Φ segmented) B 2 planes 5% 95% Trigger Interaction Region Rack Room Optical 1.2Gbps Amp/Discri. Transmit Data Merge MuTRG RPC FEE Trigger events with straight track (e.g. Dstrip <= 1) RPC / MuTRG data are also recorded on disk B/6

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