Analysis of DHCAL Data
José Repond
Argonne National Laboratory
CALICE Meeting, February 19 – 20, 2009
Kyungpook National University, Daegu, Republic of Korea
Outline
I
Vertical Slice Test
II
Simulation strategy
III
Paper I: Muon calibration
IV
Paper II: Rate capability
V
Paper III: Positron showers
VI
Paper IV: Environmental dependence
VII
Pion data
VIII
Conclusions
Monte Carlo Simulation = Integration of current knowledge of the experiment
Perfect knowledge → Perfect agreement with data
Missing knowledge → Not necessarily disagreement with data
Disagreement with data → Missing knowledge, misunderstanding of experiment
Perfect agreement with data → Not necessarily perfect knowledge
I Vertical Slice Test
Test of whole system with
Up to 10 RPCs, each 20 x 20 cm2
(Up to 2560 channels)
RPCs
Up to 9 2-glass designs
1 1-glass design
Only use RPC0 – RPC5 in analysis of e+, π+
Only use RPC0 – RPC3 for rate dependence
Absorber
For cosmic rays, muon, pions, electrons: Steel (16 mm) + Copper (4 mm)
Rate capability measurement (120 GeV protons): 16 mm PVC with whole cut out in center
Test beam
Collected data in Fermilab’s MT6 beam line
Used
Primary beam (120 GeV protons) with beam blocker for muons
Primary beam without beam blocker for rate measurements
Secondary beam for positrons and pions at 1,2,4,8, and 16 GeV/c
Cosmic Rays
Collected data for ~18 months
II
Simulation Strategy
Experimental set-up
Beam (E,particle,x,y,x’,y’)
GEANT4
Measured signal Q distribution
Points (E depositions in
gas gap: x,y,z)
RPC response simulation
Hits
Parameters
DATA
Hits
Comparison
With muons – tune a, T, (dcut), and Q0
With positrons – tune dcut
Pions – no additional tuning
Exponential slope a
Threshold T
Distance cut dcut
Charge adjustment Q0
III
Paper I: Muon calibration
Selection of plots from the paper…
Published as B.Bilki et al., 2008 JINST 3 P05001
IV
Paper II: Rate Capability
Selection of plots from the paper…
Fits theoretically motivated
Submitted to JINST, ArXiV 0901.4371
Analytical predictions
Submitted to JINST, ArXiV 0901.4371
V
Paper III: Positron Showers
Plots from the paper…
Broadband μ
Monte Carlo simulations
2GeV e+
8 GeV e+
Submitted to JINST, ArXiV 0902.1699
Monte Carlo simulations – 6 layers
Monte Carlo simulations – Infinite stack
Submitted to JINST, ArXiV 0902.1699
2GeV e+
Effects of high rates seen
Submitted to JINST, ArXiV 0902.1699
VI
Paper IV: Environmental
Selection of plots from the paper…
Data collected over
period of 18 months
Weather station added
about 9 months ago
Barometric pressure
Ambient temperature
Air humidity
Draft exists, plots being finalized
Draft exists, plots being finalized
Assume linear dependence on p,T,H
Fi(p,T,H) = Fi,0 + bi,1 Δp + bi,2 ΔT + bi,3 ΔH
with i = N,E,M
Apply correction → check RMS of distributions
Average dependence
ΔN = -1% · Δp (100 Pa) + 14% · ΔT(0C) + 0% ·ΔH(%)
ΔE = -0.06% · Δp (100 Pa) + 0.3% · ΔT(0C) + 0% ·ΔH(%)
ΔE = -0.32% · Δp (100 Pa) + 1.0% · ΔT(0C) + 0% ·ΔH(%)
… 2-glass RPC
… 1-glass RPC
ΔM = -0.25% · Δp (100 Pa) + 2% · ΔT(0C) + 0% ·ΔH(%)
ΔM = -0.003% · Δp (100 Pa) + 0.035% · ΔT(0C) + 0% ·ΔH(%)
… 2-glass RPC
… 1-glass RPC
Draft exists, plots being finalized
Cross check
Corrections not perfect,
but working
Draft exists, plots being finalized
Bonus: performance versus gas flow rate
Draft exists, plots being finalized
VII Response to Pions
Simulation needs to be redone with tuned parameters…
Data at
1, 2, 4, 8, 16 GeV (electrons rejected by Čerenkov)
Analysis separates
Non-interacting pions/muons
Pions interacting in first layers
Pions interacting later (rejected)
6 layer stack corresponding to 0.7 λI
Exactly one cluster in first layer
Distance R< 5
Number of hits in first layer <5
Pion selection
MIP selection
Number of hits in second layer ≥ 5
Number of hits in second layer < 5
Nice MIP
peaks
Gaussian
distributions
MIP selection
Mean and sigma ~independent of beam momentum
Mean not very well reproduced by simulation
→ Beam contains muons, simulation does not
(data are cleaner !!!)
Width of distributions adequately reproduced
Pion selection
Measurements at 16, 8 and 4GeV/c
Not sufficient statistics at 2, 1 GeV/c
Non-linearity due to leakage
Adequate agreement with simulation
Not sure, there is enough material for a paper
VIII
Conclusions
Analog RPC paper – published in NIM
Instrumentation paper – published in IEEE Nuclear Transactions
Muon calibration paper – published in JINST
Positron paper – submitted to JINST
First showers in a DHCAL, validity of concept, understanding of DHCAL response
Rate dependence paper – submitted to JINST
Unique contribution to understanding of RPCs, essential for operation of DHCAL
Environmental dependence paper – draft exists, plots need to be finalized
Essential information for operation of DHCAL
Pion paper – analysis to be completed
To be published?