1. Conceptual design and R&D Progress of STCF ECAL
2019/4/9
Conceptual design and R&D Progress of STCF ECAL
Yunlong Zhang
On behalf of calorimeter working group
State Key Laboratory of Particle Detection and Electronics, China
University of Science and Technology of China

2. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Outline
Motivation
STCF ECAL
Sensitive material Options
ECAL Optimization
Some Results
Photon-sensors and crystals
Electronics
Summary
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

3. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Outline
Motivation
STCF ECAL
Sensitive material Options
ECAL Optimization
Some Results
Photon-sensors and crystals
Electronics
Summary
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

4. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
1.1 关键分系统研制
Motivation
Super T-C Facility (STCF)
Ecm2 - 7GeV, luminosity ~11035 cm-2s-1 at 4 GeV
~600 m double ring
Detector
Snakes
Crab Sextupole
Wigglers
Injector
Linac
GeV
e+0.5GeV
e- 0.5GeV
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

5. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
STCF Detector
BESIII-like detector with additional considerations.
Challengers:
Higher luminosity
Same or better performance than BESIII Detector
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

6. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Outline
Motivation
STCF ECAL
Sensitive material Options
ECAL Optimization
Some Results
Photon-sensors and crystals
Electronics
Summary
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

7. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
ECAL: From BESIII to STCF
Requirements
High Luminosity
Pile up: FAST Scintillator
Radiation hardness
Gamma/neutron separation
good time resolution
Precise angular resolution
High granularity
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

8. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
ECAL: From BESIII to STCF
Barrel includes 5376 crystals arranged in 128 sectors with 42 logs.
Endcap is composed of 12 sectors, with 74 crystals each.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

9. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
High luminosity
Occupancy (from BESIII ECAL)
30 hits/ cluster
24 hits/ cluster
Occupancy of each crystal
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

10. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
High luminosity
Radiation dose (from BESIII ECAL, 7 years)
200 rad/y
100 rad/y
Only CsI and LYSO could be considered with such high radiation dose
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

11. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
High luminosity
Radiation dose (from BELLE ECAL, 10 years)
Seems that BGO could be considered in barrel.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

12. Crystal Options for STCF
2019/4/9
Crystal Options for STCF
BaF2
4.89
1280
2.03
3.1
1.5 No
300
220
600
1.2 42
4.8
TBA
BaF2:Y
4.89
1280
2.03
3.1
1.5 No
300
220
600
1.2
1.7
4.8
TBA
Fast Scintillator
2019/4/9

13. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Crystal Options for STCF
BaF2:Y
4.89
1280
2.03
3.1
1.5 No
300
220
600
1.2
1.7
4.8
TBA
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

14. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
ECAL Optimization I
Total thickness: 15X0
3 GeV gamma
Resolution
Energy linearity
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

15. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
1.1 关键分系统研制
ECAL Optimization II
Dynamic range of ECAL SD
Max edep in one crystal: 2500 MeV
Min edep in one crystal: depends on the threshold, here we set 1 MeV
Photoelectric devices
PD, APD, SiPM…
Electronics
2500 MeV
Max edep in ECAL crystal
Suppose: Light Yield is 100 p.e/MeV
Min: 100 p.e
Max: p.e；
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

16. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
ECAL Optimization III
Time response
Based on BesSim package, Statistic gamma and neutron arrival time distribution in the calorimeter
The time resolution should be better than 160 ps (500 ps / ~1 GeV
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

17. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
ECAL Optimization IV
Granularity
4cm*4cm
Sigma=3.9mm
The position resolution determines the reconstruction precision of π0 mass
Compare different size of crystals for 1 GeV γ.
4*4cm2, position resolution is 3.9 mm，
2*2cm2, position resolution is 2.7mm
2cm*2cm
Sigma=2.7mm
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

18. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
ECAL Optimization
Radiation length: 15X0
Dynamic range：1 MeV ~2500 MeV
Time resolution：160 1 GeV
ECAL crystal
Barrel：Pure CsI or BGO crystal
FWD：LYSO
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

19. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Outline
Motivation
STCF ECAL
Sensitive material Options
ECAL Optimization
Some Results
Photon-sensors and crystals
Electronics
Summary
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

20. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
crystals
Pure CsI
50%
@310 nm
Transmission
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

21. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Light yield
xp2262B for BGO and LYSO
xp2020Q for pure CsI
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
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22. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Light yield
Single p.e
signal
L.Y with PMT(pe/MeV)
L.Y with APD(pe/MeV)
BGO-1
24.2
513.4
358.4
159.3
BGO-2
23.5
633.2
456.5
202.9
LYSO-1
2.4(*)
2018.7
1343.3
597.0
LYSO-2
2.4
2586.4
1721.0
764.9
CSI-1 39
1647.5
63.8
28.4
CSI-2
1475.8
57.2
25.4
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

23. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Radiation Test
60Co source 20,000 Ci
The radiation intensity was calibrated in different position
60Co
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

24. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
APD
APD S S
Capacity（pF） 80
270 50
 50
Size
5mm*5mm
10mm*10mm
comments
Small size induced the low light collection efficiency. But the capacity is small too, so the response time could be faster.
Light collection efficiency is high, but the higher capacity induced lower time response
Multiple small-area APDs are tested together to improve signal-to-noise ratio.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

25. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
APD & Cosmic Test
muon
Cosmic Signal of LYSO
Cosmic Signal of BGO
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

26. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
WLS plate for pure CsI
EJ-286
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

27. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
CSA-based technique route
According to simulation, time measure is better than 100 ps for signals larger than 188fC (250 MeV).
High gain and low gain is used to cover the high dynamic range.
The structure of CR-RC4 can achieve a good SNR.
ADC with a sample rate higher than 25 MSPS samples the peak of the shaped signal.
CFDD and FPGA-based TDC fulfill the time measure.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

28. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
TIA-based technique route
Without integral circuits, TIA based method can solve the problem of pileup due to high hit rate, especially at endcap.
TIA transform the current signal to the voltage signal, and FADC (Sample rate > 200MSPS) digitizes the signal directly.
High gain and low gain is adopted to cover the high dynamic range.
By fitting the digitized data, precise time measure results (better than 50 ps) can be reached.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

29. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Outline
Motivation
HIEPA ECAL
Sensitive material Options
ECAL Optimization
Some Results
Photon-sensors and crystals
Electronics
Summary
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

30. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9
Summary and outlook
The main challenges of STCF detector
The high luminosity
For ECAL
Some studies from BESIII (occupancy, radiation dose et al.) tell us the option of crystals for STCF ECAL
Barrel: pure CsI; Endcap: LYSO
The APD could be used as the choices for ECAL
Two different electronics designs in parallel
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

31. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Outlook
Optimize the ECAL overall design
The APD devices neutron radiation test
The wavelength shift materials test
Test crystal+APD+electronics unit
Response to cosmic rays
Use laser to test the unit
Dynamic range
Time resolution of different amplitude
Pile up
GSO and BaF2:Y crystals could be considered in future?
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

32. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

33. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Results
Improved light response uniformity (LRU), L.O. & RMS, especially for A end coupling
Large sample
Ref. : Presentation N37-04 by Junfeng Chen in IEEE NSS/MIC 2018 at Sydney, Australia
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

34. Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
Specification
2500 MeV
Two APDs on each scintillator for backup and large active area.
Based on MC simulation, energy deposition is about 2.5 MeV~2500 MeV on each scintillator. LY of CsI is 100 pe/MeV, and the gain of APD is about 50. Dynamic range of electronics is about 2 fC~2000 fC.
The capacity of APD is 270 pF, which may cause a noise of 2 fC.
Time measure is needed, and precision is demanded to be better than 100 GeV according to MC.
Very high hit rate because of the high intensity, 100 kHz at barrel and even higher at endcap.
Two technique route: TIA-based and CSA-based.
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9

35. VUV-4 has a much better performance than VUV3
Hamamatsu S CQ-02
SiPM with VUV response is available: QE = 22% at 220 nm
VUV-4 has a much better performance than VUV3
Joint Workshop of future tau-charm factory, Orsay - Dec. 6th 2018
2019/4/9