1. Beam test of Silicon-Tungsten Calorimeter Prototype
7th ACFA workshop, Taipei 2004/11/10
Youngdo Oh (Kyungpook National University)
On behalf of Ewha womans University: S.J. Baek, H.J. Hyun, A.L. Jeong, S.W. Nam, I.H. Park, J. Yang Korea University: J.S. Kang, S.K. Park, J.H. Choi Kyungpook National University: Y.D. Oh, K.H. Han, D.H. Kim, J.S. Seo, U.C. Yang Seoul City University: I.K. Park Sungkyunkwan University: I.T. Yu, Y.P. Yu Yonsei University: B.S. Jang, S.H. Jeong, J.H. Kang, Y.J. Kwon
I’d like to talk about silicon calrorimetr. Actually what I want to talk about is a sort of report on our experience on silicon production.
Let me start with why si is considered and what to be considered, and I will show you our work on silicon for a space experiment. And finally a few words on remarks.

2. Beam test Condition Beam Test : Aug. 30 – Sep. 7 2004
SPS : 400GeV proton beam
Beam interaction with a target (T2)
Beam cycle length 18.0 sec.
4.8 sec spill length
User controls test beam particle type,
energy(10,20,30,50,80,100,150 GeV),
focus, and the intensity
Test beam energy accuracy +/- 0.3%
Beam particle purity > 95%

3. Tungsten and mechanics
Tungsten size : mm X mm ( ~ sensor size)
purity : close to 99% ( Rm = 9mm)
thick : 3.5 mm (= 1 X0)

4. Sensor and analog electronics
The heritage from space experiment
1mm inactive gap between sensors
Silicon Sensor
32 pixels
in a layer
131mm X 115mm
Analog Board
Aluminum mm
pcb structure 10 mm
Tungsten mm
Aluminum mm
15 mm
Rt= a layer / tungsten = 15.0/3.5 = 4.8
(CALICE ~ 2)
Eff. Rm = 9mm * (1 + Rt) = 52mm
Total 20 layers = 20 X0, 30cm thick
19 layers of shower sampling

5. Assembly & Mechanic support
Tungsten 1X = 35mm
Rt= a layer / tungsten = 150/35 = 4.8
(CALICE ~ 2)
Total 20 layers = 20X
(a CALICE prototype.: 30 layers 30X)

6. Assembly

7. Beam Test Activity beam 1. Tunning time delay
2. Detector Alignment run
3. MIP calibration of all channels
(no tungsten)
4. Data Run (20 layers)
(electron 150,100,80
50,30,20,10 GeV
hadron 150 GeV
muon 150 GeV)
5. Data Run (10 layers)
: to study transverse shower
profile
beam

8. Monitoring data & alignment
Detector alignment
Data monitor : online, offline

9. Data Summary (50GB)
Beam
Beam Energy (GeV)
files
Etc
4x4x20
Muon
150 23
TD Check
Electron 50 33
TD Check
Pion
150 35
Sensor scan
4x4x20
Tungsten
Pion
150 12
Muon
150 42
Electron
150,100, 80,50, 30 ,20 ,10
399/37~89
4x8x10
Tungsten
Pion
150 3
Muon
150 18
Electron
150, 100, 50, 20
162/36~48

10. Channel Scan for MIP calibration
Channel summary
noisy(~10%)
ADC unstable(~5%)
deal channels (~5%)
One panel of sensor shown as an example

11. Gain Calibration of Individual Channels
Pedestal :
Gaussian Fit
Mean :
Sigma : 7.2
150 GeV Muon Beam
Scan over All 640 Channels
Size of signal from the pedestal level of a channel is used to calibrate the channel
S/N (signal to noise rate) = 5.2
( )/7.2
Signal :
Landau Fit
Peak : 5243
ADC Counts

12. Detector Response to Different Particles
First look of data
Just sum of all channels
Including noisy, bad and dead
channels
Not optimized detector
No calibration
No beam position information
considered
50 GeV Electron
50 GeV pion
150 GeV Muon
Total ADC of an event / 640

13. Detector Response to Electron Beam(sum of all channel)
First look of data
150 GeV Electron
100 GeV Electron
80 GeV Electron
50 GeV Electron
30 GeV Electron
20 GeV Electron
10 GeV Electron
Total ADC of an event / 640

14. Calorimeter Calibration : ADC vs. Beam Energy
First look of data
Very preliminary
Total ADC above pedestal / 640
Fit to Straight Line
-> Slope 4.2 (ADC/GeV)
Electron Energy in GeV

15. Energy Resolution vs Energy
First look of data
Very preliminary
dE / E (%)
Electron Energy in GeV

16. Summary
1. Beam test of Silicon-Tungsten during Aug. 30 to Sep. 7 at CERN
2. ~50GB data collected using electron, muon and pion beam
3. Analysis is under way
: noisy, unstable, dead channel. leakage due to large effective RM (52mm)
not optimized electronics and detector for LC calorimeter
4. Require detailed MC study for the accurate geometry
5. Si/W Detector is working .
The result will be presented in next LCWS.
6. In Korea, R&D for LC calorimeter is going on.
This beam test experience will give positive idea for R&D activity.