1 / 15

RPC Update

RPC Update. What’s new since Cornell…. Jos é Repond Argonne National Laboratory. American Working Group On Linear Collider Calorimetry 16 September 2003. Outline. • New chamber construction • Tests of geometrical acceptance • Multi-channel VME boards • Simulation studies

jbowlin
Download Presentation

RPC Update

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RPC Update What’s new since Cornell… José Repond Argonne National Laboratory American Working Group On Linear Collider Calorimetry 16 September 2003

  2. Outline • New chamber construction • Tests of geometrical acceptance • Multi-channel VME boards • Simulation studies • Plans for the next few months

  3. Chamber construction Argonne built 3 chambers early in 2003 - extensive tests with single pads - extensive tests with multi-pads - geometrical tests (→ see later) Boston University(John Butler and Meenakshi Narain) - initiated construction of additional chambers - first iteration on channel construction - all other parts on hand - cosmic ray test stand is set-up; gas is ordered - comparison of multi-gap chambers with single gap chambers - tests with different gas mixtures - construction of larger chambers (33 x 100 cm2)

  4. Geometrical Acceptance Cosmic ray test stand at University of Chicago Abigail Kaboth,Ed Blucher, Mark Oreglia and Sasha Glazov Trigger Counters RPC Drift Chamber z y x Drift Chamber track with 250 μm resolution Running in streamer mode…

  5. 1.1 mm 0.64 mm Spacers (5 cm apart) Efficiency across the spacer direction scan HV = 7.4 kV HV = 7.6 kV Select vertical tracks only Half width about 1.8 mm Half width is about 1.1 mm Є ~ 15% x 3 mm = 45% mm = 100% x 0.45 mm Spacer Ø is 0.64 mm

  6. Efficiency across and along the spacer direction High Voltage lead HV = 7.4 kV HV = 7.4 kV Along HV = 7.6 kV Across Efficiency drops away from HV lead Effect reduced with higher HV setting Effect not observed along spacer Effect (across) corresponds to Δ=100 V/6 cm Still to be investigated in more detail

  7. Multi-channel VME readout Gary Drake (ANL) and Charlie Nelson (FNAL) 6U x 160 VME board VME64 compliant Contains 64 discriminators Optional amplification Records time-stamps of hits and hit patterns

  8. 64 channels of discriminator Built as 2 – channel SIPs Fully differential input Amplifier can be jumped across Common threshold voltage (using on – board DAC) When one (or more) discriminators fire Latch value of timestamp counter Record state of all 64 channels Resulting data words written to readout buffer

  9. Timestamp counter Runs at 10 MHz → 100 ns resolution Reset once per second from timing module in crate Status SIPs Design complete Layout complete Fabrication complete Assembly complete being tested VME boards Design complete Layout complete Fabricated 4 boards Assembly completed being tested Software Using VXworks Collaboration with NuMI Off-axis Potential hang-up Alternative based on PCI – VMEbus adapter being investigated

  10. Simulation of 1 m3 Prototype Lei Xia (ANL) Conclusions presented at Cornell EM and HAD showers appear narrower in a DHCAL with RPCs compared to a DHCAL with Scintillator This effect is due to larger and wider cloud of deposits from electrons (and protons in HAD showers) in Scintillator compared to RPCs The results were obtained with a threshold for hits E0 at 0 With increasing E0 in Scintillator Radius and E resolution of EM showers decreases Radius of HAD shower remains large (due to protons)

  11. Digital readout – Pad size and linearity • Definition: Linearity • Fit the detector response • with a simple function: • N(hits) = P1 x E(shower)P2 • P1 and P2 are fitting • parameters. • This simple function works • amazingly well. • 2. P2 = 1 means perfect • linearity 2 Total number of hits Pad size = 40x40mm Electron energy (GeV) RPC as active media

  12. Pad size and linearity: Electron Number of hits increases as pad size gets smaller Energy resolution gets better Detector linearity gets better Very good for pad sizes around 0.2 x 0.2 mm2

  13. Pad size and linearity: Pion – surprise! Detector has linear response only for pad sizes around 5 x 5 mm2 For smaller pad sizes: response over – linear! Degrades energy resolution Why?

  14. Pad size and linearity: Cross-talk? -- No! Change of gas gap thickness from 1.2 mm to 0.1 mm Reduces cross-talk Non-linearity remains the same

  15. Application of graphite layer Workable paint in hand Explore silk screening Construction of chambers Build single – gap chambers Design larger chambers Geometrical efficiencies Investigate effect of HV leads and spacers Gas Investigate different mixtures Multi-channel VME readout Debug, program, use… Plans for the next few months

More Related