RPC production and performance Chong Kim Korea university RHIC spin workshop, Seoul National Univ.

Outline A.RPC upgrade B.RPC station 3 status 1.Structure of the station 3 2.Module production and QA 3.Half octants production and QA C.Summary and Perspective RHIC spin workshop, Seoul National Univ.2

RHIC spin workshop, Seoul National Univ.3 RPC 1 RPC 3  RPC upgrade: provide timing & rough position information A. RPC upgrade

B. RPC station 3 status - 1. Structure of the station RHIC spin workshop, Seoul National Univ.4  Detector outline  RPC station 3 is composed of 16 half octants  A half octant composed of 3 RPC modules (type A, B, C)  Each module is a double-gap RPC (independent of type) which satisfies PHENIX requirements RPC3 Station 3 (16 half octants) A half octant (3 RPC modules) Module C Module B Module A

PHENIX RPC factory layout B. RPC station 3 status - 1. Structure of the station RHIC spin workshop, Seoul National Univ.5 Burn-in test stand and half octant storage half octant components and hardware storage Gas system RPC gap & module storage with humidity control Half octant assembly area Half octant transport table Main tent (module assembly & QA) Entrance

B. RPC station 3 status - 2. Module production and QA RHIC spin workshop, Seoul National Univ.6  PHENIX muon trigger RPC  Based on CMS endcap bakelite RPC technology and expertise  Each station 3 (north & south) requires 48 (16×3) detector modules  All of station 3 detector modules (both sides) were produced successfully Station 3 - module C PHENIX RPC requirements Time resolution  3 ns Average cluster size  2 strips Efficiency> 95 % Rate capability0.5 kHz/cm 2 # of streamers< 10 %

RHIC spin workshop, Seoul National Univ.7 B. RPC station 3 status - 2. Module production and QA Module assembly Lay down Cu foil on the Mylar sheet (+ frame) Place lower gap into Cu foil & Connect Polyethylene gas tubes Connect CPE cable to H.V cable on the bottom RPC gap Connected gas tube

RHIC spin workshop, Seoul National Univ.8 B. RPC station 3 status - 2. Module production and QA Module assembly (continue) Preparing readout strip (attach signal cables) A signal cable attached to the strip Place readout strip on the lower gap Place upper gap on the readout strip Sideview of stacked RPC gaps & strip Signal cables attached to the strip and the upper gap

RHIC spin workshop, Seoul National Univ.9 B. RPC station 3 status - 2. Module production and QA Module assembly (continue) Connect gas tubes to the upper gap Connect CPE cable to the H.V cable (upper gap) Before wrap the Cu foil After wrap the Cu foil Fully assembled RPC detector module

B. RPC station 3 status - 2. Module production and QA RHIC spin workshop, Seoul National Univ.10 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 RPC cosmic ray test stand - event display cosmic ray trigger scintillators RPC readout strip planes cosmic ray trajectory  QA(Quality Assurance) items after module assembly: Noise rate, Total(2D) and strip efficiencies, Time resolutions, Cluster size

B. RPC station 3 status - 2. Module production and QA RHIC spin workshop, Seoul National Univ.11 Noise rate: RPC H.V = 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. H.V Efficiency of a module (%) vs. H.V with different Threshold Cluster size of a module vs. H.V with different Threshold Operation voltage PHENIX requirements

B. RPC station 3 status - 2. Module production and QA RHIC spin workshop, Seoul National Univ.12 # of strips vs. noise rate (individual module) # of strips vs. noise rate (all 48 modules) Results of station 3 - north  # of strips vs. noise rate (all modules)  # of modules: 48  H.V: 9.5 kV  FEE threshold: 160 mV  Average noise rate: 0.52 Hz/cm 2  Only 7 strips are over 10 Hz/cm 2  strips vs. noise rate (individual module)  H.V: 9.5 kV  FEE threshold: 160 mV  Black histogram: module A  Blue histogram: module B  Red histogram: module C All results are compliant with PHENIX RPC requirements

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.13 Half octants assembly Route service lines of the module for the assembly Insert prepared modules to the HO frame Connect & Re-route service lines to the patch pannel View from inside of patch pannel Insert prepared modules to the HO frame (2) Insert prepared modules to the HO frame (3)

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.14  RPC Half octants status  All half octants (total 32, north & south) were produced successfully  North: QA, installation, integration and commission were completed  South: QA is underway (15 of 16 QA finished & installed), preparing for integration RPC half octant placed on assembly table at the RPC factory in BNL

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.15  Average noise rate: 0.37 Hz/cm 2  Modules are in Faraday cage Integrated result of half-octants QA AT FACTORY

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.16 RPC station 3 – north installation

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.17 RPC station 3 - north installation completed

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.18 RPC TDC RackIntegration completed

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.19  Goal: c heck performance of the RPCs at stand-alone mode  Full electronics readout chain  Noise rate  Ground  Cosmic ray background  H.V stability  Dark current  etc.  Progress  Most of the items progress favorably  Problem in several half octants’ (6 of 16) H.V holding & Dark current  Cause: gas balance (mixed gas is heavier than normal air)  Careful pressure control required by each half octants’ position  PHENIX technicians and RPC factory crews are working on to resolve it Commission of RPC3 - north

B. RPC station 3 status - 3. Half octant production and QA RHIC spin workshop, Seoul National Univ.20 1W2W3W4W5W6W7W8W1E2E3E4E5E6E7E8E Assembly Done Leakage test Done QA Done OnDone Burn-in Done 06/14 – 07/26 Done 06/14 – 07/26 Done 07/01 – 08/04 Done 07/01 – 08/05 Done 08/05 – 09/07 Done 08/09 – 09/07 Done 08/09 – 09/01 Done 08/09 – 09/01 Done 08/13 – 09/08 Done 08/13 – 09/08 On 08/13 – On 08/13 – On 08/13 – On 08/13 – On 08/13 – On 08/13 – Status In Leakage test Done H.V test Done Electronics test Done Status of RPC3 - south half octants  Done: completed, On: ongoing, In: Installed

C. Summary and Perspective RHIC spin workshop, Seoul National Univ.21  Summary  Production and QA of all of the station 3 RPC modules were completed  Production of all of the station 3 half octants was completed  North: Completed (QA, installation, integration and commissioning)  South: QA is underway, installation in progress, preparing for integration, commissioning will be early of run-11  Perspective  Preparing for the operation at run-11 (incoming run)  Integration of RPC DAQ into PHENIX DAQ  Integration with MuTrig  RPC station 1:  Gap production was completed  Prototype test is underway

C. Summary and Perspective RHIC spin workshop, Seoul National Univ.22 RPC Installation for Station 3 South by October + Absorber Installation RPC Production and Installation for Station 3 North by October RPC Production for Station 1 North by December RPC Installation for Station 1 during shutdown PHENIX RPC schedule

Thanks! RHIC spin workshop, Seoul National Univ.23

RHIC spin workshop, Seoul National Univ.24 Backup - W measurement at PHENIX muon arms  W measurement at RHIC:  Goal: study the polarization of the flavor separated quarks/antiquarks  Meathod: by measuring muons decayed from W bosons A L W : single spin asymmetry p: beam polarization N L(R) (W) : # of events contains the muons from W with corresponding helicity (L or R) Spin crisis and W measurement at RHIC  Spin criris:  proton spin is not a simple sum of its constituent quarks  Component-by-component approach: flavor separated quarks/antiquarks, gluons, and their angular momenta

Muon Hadron Absorber Muon Tracker (MuTr) Muon ID (MuID) RHIC spin workshop, Seoul National Univ.25 Current PHENIX muon arms  Acceptance  1.2 < |η| < 2.2  Δφ = 2π  Muon Tracker (MuTr)  3 stations of CSCs  80 cm of steel & copper absorber  Muon ID (MuID)  5 gaps of larocci tube in x & y directions  Total 80 cm of 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 - W measurement at PHENIX muon arms

RHIC spin workshop, Seoul National Univ.26 Simulated muons into Muon Arms (2000 pb -1, with PYTHIA 5.7) Current Muon trigger at PHENIX 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 upgrade)  Total interaction rate: 9 MHz (18 MHz)  DAQ limit: 2 kHz (for muon arm)  Required rejection factor (RF): 4500 (9000)  The current muon trigger can accepts muons above 2 GeV/c, but DAQ cannot take full rate at 500 GeV  Required 1 st level rejection factor for W at 500 GeV: 9000  Need momentum sensitive muon trigger and fast readout electronics for muon tracker  The upgraded 1 st level trigger will select events with muons of p T  20 GeV/c from W boson decay Backup - W measurement at PHENIX muon arms

RHIC spin workshop, Seoul National Univ.27 Characteristics of double gap RPC in avalanche mode  Fast response: suitable for the trigger device  Good time resolution: ns for M.I.P  Good spatial resolution: typically ~ cm (Determined by the read-out strip width and cluster size)  Efficiency: > 95 % for M.I.P  Rate capability: kHz/cm 2  Low cost: bakelite (resistivity  cm)  Noise rate: Hz/cm 2 for  cm  Typical strip multiplicity:  Typical gas mixture:  95% C 2 H 2 F 4 (Tetrafluoroethane, R134A, base gas for avalanche mode RPC) + 4.5% i-C 4 H 10 (isobutane, photon quencher) + 0.5% SF 6 (electron quencher)  20 – 40% relative humidity Backup - Characteristics of the RPC Cu foil (2 mm) Mylar sheet Module frame (Al)

RHIC spin workshop, Seoul National Univ.28 Backup - Module production and QA Module assembly flow Cu foil (2 mm) Mylar sheet Module frame (Al) Lay down a Mylar sheet & Cu foil on the bottom module frame Place lower gap & Attach service lines (H.V, gas) Prepare readout strips & Place it on the lower gap Place upper gap on the strip & Attach service lines Put a Mylar sheet on upper gap & Wrap the cu foil Close module frame

RHIC spin workshop, Seoul National Univ.29 FEE CAMAC modules 4434 CAMAC scaler & pdaq machine A RPC module HV (CAEN) LV (MEGAPACK) Raw signal LVDS signal ECL signal Converting LVDS to ECL Visual scaler Backup - Module logic for noise rate test

RHIC spin workshop, Seoul National Univ.30 Backup - Module logic for cosmic ray test FEE TDC & new pdaq machine HV (CAEN) LV (MEGAPACK) Raw signal LVDS signal RPC modules (usually 10)