1. 3rd Open Meeting of the Belle II Collaboration
Cosmic ray test
for Phoswich option
Insu Lee, Taeyoung Kim , Sunghyun Kim
and ByungGu Cheon
Hanyang University
7 July, 2009
3rd Open Meeting of the Belle II Collaboration

2. Outline Motivation Cosmic ray test Summary
ECL electronics for Belle II

3. Phoswich option for Belle II
A phoswich ('phosphor sandwich') is a combination of scintillators with dissimilar pulse shape characteristics optically coupled to each other and to a common PMT. Pulse shape analysis distinguishes the signals from the two scintillators, identifying in which scintillator the event occurred.
CsI(Tl)
Slow signal
Pure CsI
Fast signal
Idea:
re-use (possibly) un-damaged rear part of endcap CsI(Tl) crystals
Merit as Belle II Endcap crystal option :
* Radiation damage only to front ~10 cm of crystals
* High energy signals  enough signal in CsI(Tl) crystals  do not lose resolution
* Fast/Slow  another handle for shower correction by knowing shower shape
* Fast trigger signal using fast signal  blind to beam background
* Much cheaper than other options such as pure-CsI only, BSO or PWO-II

4. Cosmic ray test setup muon 5cm PMT (pure) 10cm CsI (Tl) 20cm PMT
Plastic Scintillator
5cm
PMT
Plastic Scintillator
CsI
(Tl)
20cm
(pure)
10cm
Fedora core 6
FADC 400MHz
Linux PC
Phoswich
PMT

5. Typical event shapes Two types of signals has been detected.
Pure 는 412개 Tl 588개
Two types of signals has been detected.
CsI(Tl) and pure CsI oriented signals

6. Compared with separated Xtals
CsI+CsI(Tl)
CsI+CsI(Tl)
CsI(Tl)
CsI

7. Summary / Plan Summary - Pulse shape discrimination is unclear.
- Pure comp. seems to be smeared in Tl comp.
- It seems re-emission of pure comp. in CsI(Tl).
- Lots of works are needed to be realized.
Plan
- Try to test phoswich prototype at beam test facility.

8. ECL electronics for Belle II
Most of electronics are considered to produce in Korea.
- Trigger module prototype design is still going on.
- Barrel shaper prototype has been produced.
- Endcap shaper / Collector module / Preamp
- We will develop them together with BINP group.
Mass production
- Trigger: FAM (60) / TMM (10)
- Barrel shaper (400) / Endcap shaper(200)
- Collector (60) / Preamp (2000)

9. Backup slides

10. sBelle calorimeter trigger
Feature :
Much simpler electronics chain (2 steps) than Belle
More flexible trigger algorithm design than Belle
1st step (FAM) : 10MHz/12bit FADC + FPGA
2nd step (TMM) : cascade/partitioning FPGAs
Bulky copper cables  52 optical fibers
Simple monitoring scheme
Simultaneous handling of CsI(Tl) and pure-CsI signals
Current status :
We now investigate fast shaping signal from new Shaper.
FAM core firmware algorithm has been tested.
TSIM MC study has been performed w/ g4superb.
Plan :
FAM/TMM prototype design is still going on.
Basic test of Shaper/FAM/TMM readout chain
Under real environment before Belle shutdown
Belle
sBelle