1. The DHCAL: an overview José Repond Argonne National Laboratory
CALICE Collaboration Meeting
Shinshu University, Matsumoto, Japan
March 5 – 7, 2012

2. DHCAL Construction We have This took ~ 2 years
Built 205 RPCs (32 x 96 cm2)
Built 320 readout boards (32 x 48 cm2)
Built 34 Data Collectors (DCOLs)
Built 6 Timing and Trigger Modules (TTMs)
Assembled 52 detector layers
Assembled a gas mixing and distribution rack
Built a low voltage power supply and distribution system
Acquired a high voltage power supply system
Written, debugged and commissioned all data acquisition Firm- and Software
This took ~ 2 years

3. DHCAL Past Test Beam Activities
Date
DHCAL layers
Tail catcher layers
Total RPC layers
Configuration
Readout channels
Number of
Muon events
Secondary events
October 2010 38
DHCAL
350,208
1.4M
2.9M
January 2011 13 51
DHCAL + TAIL CATCHER
470,016
1.6M
5.2M
April
2011 14 52
+ CALICE Si-W ECAL
488,952
2.5M
7.3M
June
479,232
3.3M
6.0M
November 50
Minimal Absorber
460,800
0.6M
4.5M
TOTAL
9.4M
25.8M

4. Configuration in November 2012 Run
50 layers, no absorber
→ 13.4 X0
→ 1.6 λI
460,800 readout channels

5. (still not working to this day)
Tertiary Beam at FTBF
Setup
Additional target inside enclosure
→ Particles between 0.1 and 2.0 GeV/c
2 analyzing magnets
Time-of-flight for particle identification
→ 2 Scintillator with CAMAC readout system
4 wire chambers for momentum analysis
→ Also with CAMAC based readout system
Never worked properly
(still not working to this day)
Gave up on using tertiary beam
(moved DHCAL back and forth)

6. Statistics collected in November 2011
Beam
Momentum
Number of events
(including calibration)
Total number of events
Secondary with blocker
Broadband
muons
598k
Secondary 32
62k
1,306k 10
226k 8
205k 6
154k 4
92k 3 2
256k 1
218k
Tertiary with
DHCAL in secondary position
Broadband muons
2,266k
Tertiary
0.2 – 2.0 2k
Grand TOTAL
4,355k

7. The DHCAL was almost perfect…
Dead RPC
None
Noisy RPCs
Some noisy channels (close to grounding connectors)
Some noisy areas → Negligible effect on data
Dead ASICs
Currently 27/7200 or 0.38% ← stable
Dead FEBs
High voltage
WIENER: new system: perfect!
Low voltage OK

8. DHCAL Data Analysis a) Instrumentation paper (Gary, José)
Needs calibration of thresholds (in progress)
First draft almost ready
b) Noise measurement (Qingmin, Guang, Lei)
Progress with categorizing noise events
Technical note exists
c) Simulation of DHCAL response (Kurt, José)
Progress in understanding GEANT4
Progress with simulation of RPC response
d) Muons (Daniel, José)
Analysis essentially complete
e) Pions and positrons (Burak, Jacob, José)
Progress with particle ID
Progress with software compensation
Needs simulation
Technical note of response exists
f) Fractal analysis (Manqi)
Great stuff
Needs calibrated data
Uncalibrated
Calibrated

9. DHCAL Future Test Beam Activities
At CERN, with Tungsten absorbers
Date
DHCAL layers
Tail catcher layers
Total RPC layers
Configuration
Readout channels
Beam
May 2012 38 14 52
DHCAL
479,232 PS
June 2012
SPS
Fall 2012
Transport structure
Design finalized
Construction began
Additional information from Erik van der Kraaij

10. Current and Future R&D 1-glass RPC High rate RPC
Assemble 32 – 96 cm2 RPC (not initiated yet)
Test in Cosmic ray test stand
High rate RPC
Semi-conductive glass being developed by COE college
First samples with rough surface, diameter of ~ 5 cm and desired resistivity
Samples large enough and smooth enough for building RPCs by April
Planned tests with sources and in cosmic ray test stand
HV distribution system
Iowa developing high voltage distribution system
First test of prototype powering RPC successful
Now implementing current monitor circuitry
Hot topic in the RPC community
Needed for realistic RPC-based calorimeter module

11. Early Carrier Proposal: Nano-second Timing
CLIC environment
Requires 1 ns time-stamping to reject beam related backgrounds
ANL RPCs
Timing resolution of ANL RPCs measured to be ~0.8 ns
(Measurement by University of Michigan)
Current DCAL III chip
Pulsed at 10 MHz
→ Time resolution ~ 100 ns
Development of DCAL IV chip
Reduced power consumption (factor of 10?)
Time-stamping at the 1 ns level

12. Design of Lepton Collider Detector
Novel concept of Hadron calorimeter
Active elements oriented radially (like ATLAS tile-cal)
Provides straightforward solution to
Routing of supplies (HV, LV, gas)
Number of different chamber sizes
Number of different readout board sizes
Development of mechanical design
Work being done at Argonne
Design includes certain level of detail
Simulation of response
Model with first set of design parameters
implemented into GEANT4
University of Oregon working on analysis
Results to be used to fine-tune design parameters
Particle
Simulated pion shower in HCAL

14. ATLAS Muon Trigger Phase I upgrade Proposal Benefit Collaboration
Replace small wheel with
High-rate, high spatial resolution RPCs
Benefit
Improved momentum resolution
Improved trigger turn-on curve
Collaboration
University of Michigan and Argonne

15. Conclusion
We are busy
Lots to do…