DHCAL with RPC Update

DHCAL with RPC Update What’s new since June… Current collaborators www.hep.anl.gov/repond/RPC_US.html José Repond Argonne National Laboratory CALICE Meeting, DESY, Hamburg, Germany 7 - 8 December, 2004

Pick-up pads Graphite Signal HV Gas Resistive plates Chamber construction RPCs are… simple, robust, cheap, quiet, well understood, reliable adaptable to different requirements (TOF, high efficiency, large area…)

RPCs with single – pad readout Chamber technology well understood

Digital Readout Built VME readout system Handles 64 channels Provides hit pattern and time stamp Tests with RPCs in avalanche mode → requires additional amplifiers on the pads 64 1 x 1 cm2 pads Trigger area Readout pad array Measurements of pad multiplicities and noise rates versus efficiency

Results in avalanche mode Hit efficiency Decreases with threshold Hit multiplicity Decreases with threshold

Standard chamber design (On-board amplifiers) Pad array Mylar sheet Resistive paint 1.1mm Glass sheet 1.2mm gas gap GND 1.1mm Glass sheet Resistive paint -HV Mylar sheet Aluminum foil Low noise Hit multiplicity M 1.6 – 1.7 for efficiency = 95 % 1.4 – 1.5 for efficiency = 90 % Low noise ~0.1 Hz/cm2 M not sensitive to operating HV

Standard chamber design Multiplicity versus Efficiency Comparison of different chambers Lower multiplicity for High surface resistivity 1 – gap chambers

(On-board amplifiers) 1.6mm PC board Pad array 1.2mm gas gap 1.1mm Glass sheet Copper tape -HV Mylar sheet Exotic chamber design Hit multiplicity M ~1.1 for efficiency > 95 % Low noise 0.1 – 0.2 Hz/cm2 M not sensitive to operating HV Additional bonus Thinner chamber ~ 5.4 mm Low noise

Standard Exotic

Rate Measurements COSMIC RAYS and SOURCES Sr90 source Variable rates Measurement Self-triggered Efficiency for MIPS Measurement triggered by scintillation counters RPC Trigger counters Problems with this method - Rates from source not uniform over area - Efficiency drop affects rate measurement - Source provides e-, not MIPs - Cosmic ray trigger contaminated MIP

With fixed rate from source… Current increases with HV - Linear behavior - Difficult to extract bulk resistivity Measured rate increases with HV - Low HV: increasing efficiency - At ~6.8 kV efficiency ~ 100% - Above 6.8 kV: sensitive to area outside the 64 pads

Measured MIP efficiency - Good up to rates of 50 Hz/1 cm2 - Some dependence on HV setting → Higher is better With fixed HV… • Beware!!! • Measured rate affected by • Inefficiency • Source (e-) of rate Measured current increase with rate - Strong non-linearity → Inefficiency Rate capability at least 50 Hz/cm2

Comparing Air4 and Air9… Standard design somewhat better

HV Bulk Resistivity of the Glass Measurement with DVM Recent result Observed dependence on Temperature Result ρ = 4.7· 1012 Ωcm …similar to measurements by other groups

Electronic Readout System 40 layers à 1 m2 Real challenge 400,000 readout channelsCheap (≤ 1$/channel) 1 cm2 readout pads Low cross-talk, noise… Conceptual design of system I Front-end ASIC II Data concentrator III VME data collection IV Trigger and timing system

Front-end ASIC 64 inputs with choice of input gains RPCs (streamer and avalanche), GEMs… Triggerless or triggered operation 100 ns clock cycle Output: hit pattern and time stamp ASIC performance specified in 41 page document

ASIC design work at FNAL Abderrezak Mekkaoui James Hoff FNAL Ray Yarema First design meetings in February Design work started in June Digital section completed in August Analog part to be implemented First submission hopefully in March 2005

System design and prototyping Meeting at Argonne on December 17th Presentation of status of GEM and RPC R&D Overview of electronic readout system Discussion of individual parts of RO system Discussion of other systems Gas, HV… Assigning of projects to different groups Attendance from Boston, Chicago, FNAL, Iowa, Kansas, UTA, Washington….

Discussion of Steel versus Tungsten Study by Steve Magill 30% more hits in HCAL with W Steel Single particle resolution 5 GeV π Analog ECAL Digital HCAL σ/μ ~ 28% σ/μ ~ 22% Tungsten

- Applying PFA to e+e → Z0 Events RMS = 6.2 GeV RMS = 6.4 GeV Steel Tungsten σ/μ = 3.7% σ/μ = 4.5% σ/μ = 7.6% σ/μ = 7.6% …remember the goal is RMS ~ 3 GeV More work needed!!!

Test beam at FNAL Test beam parameters matched to our needs Momentum between 5 and 100 GeV Protons, pions, muons, (electrons?) Intensity can be reduced Up to 6 m in lateral space available Beam time structure Resonant extraction working! Spills of 600 ms → could request longer spills 1 spill/minute → will increase to (5 – 10)/minute Status FNAL very interested in helping out Recently increased LC R&D effort Draft of MoU with FNAL exists will improve duty cycle

Memorandum of Understanding Main requests to FNAL Extension of momentum range • from 5 GeV/c → 1 GeV/c Improvement to duty cycle • longer spills • more spills per minute Tagged particles • electrons with E up to 25 GeV Will be discussed in Steering Board meeting

Time scales R&D with chambers Test chamber with thinner glass Test chamber with larger dimension Electronic readout system Design and prototype ASIC Specify entire readout system Prototype subcomponents Construction of m3 Prototype Section Build chambers Fabricate electronics Tests in particle beams Without and with ECAL in front FY 2004 CY2004 and early 2005 CY2005 CY2006

Financing of the Prototype Section Cost estimate (M&S) Resistive Plate Chambers $10,000 FE ASIC $150,000 FE readout board (pads and ASIC; 360 boards) $90,000 Data concentrator boards (need 120; each with 4 FPGAs) $45,000 VME readout (40 cards) $140,000 Power supplies, optical fibers, HV… $60,000 ___________ Grand Total $495,000 + 50% contingency Sources of funding ANL - HEP: planning document awards highest priority among projects for the future LDRD (ANL) $181,500 LCRD (DOE) ???? UCLC (NSF) ???? MRI (NSF) ???? US-Japan Funding Agency ???? European collaborators ????

DHCAL with RPC Update