Post on 20-Dec-2015
R&D on CsI(Tl) + APD
Optimisation of the energy resolution
M. Gascón
I.Durán
R3B calorimeter
Total absorption efficiency 80 % (Eg=15 MeV lab) Very large crystals
Eg sum s(Esum)/<Esum> <10% (same as DE/E)
g Multiplicity s(Ng)/<Ng> < 10% Moliere Radius
DE/E for g 2-3 % Scintillation propertiesDetector granularity
DE/E for p (up to 300 MeV)Calorimeter for p
3 % Large crystalsDynamic range
Large dynamic range for detecting p,g
Inner radius 35 cm ( house Si trackers)
Main characteristics (from R3B Tech Proposal) :
R&D on crystals + readout systems
Design based on CAD + GEANT4 full simulations
see http://www.usc.es/~genp -> calorimeter -> reports and talks
Calorimeter sectors
Demonstrator meeting, Madrid May-09
Due to the Lorentz boost we identify three sectors:
ECM = 10 MeV
β = 0.82
88
15
45130
Crystals
!?
R3B/EXL meeting Milan Oct-06
Crystals
M. Mozynski et al., NIM A 485(2002)504 (API LAAPD)
CsI (Tl) 10x10x10, 10x10x50 ,10x10x100, 10x20x170 mm
CsI (pure) 10x10x10, 10x10x50 ,10x10x100 mm
LaCl3(Ce) 10x10x10, 10x10x50 ,10x10x100, 10x20x170 mm
Standard 10-stage, 19 mm tube, lima glass, Green bi-alkaliXP1901
Standard 10-stage, 19 mm tube, fused silica, UV bi-alkaliXP1918
Standard 10-stage, 25 mm tube, borosilicate glass, bi-alkaliXP3102
19 mm2 UV extended (200-1000 nm)S5345+ API
10x10 mmS86641010(PANDA)
5x5 mmS8665-55 (CMS)
St
Gob
ain
Pho
toni
sH
amam
atsu
R3B/EXL meeting Milan Oct-06
Material we used for test
R&d on crystals and APDs
Crystals from StGobain (France) tested coupled to LAAPD from Hamamatsu (Japan) and API (USA)
R3B/EXL meeting Milan Oct-06
Data-taking setups
Standard pulse-height analysis :
- preamplifiers: Canberra 2001A, Ortec R142
- Shapping amplifier: Canberra 2022
- Multichannel analyzer: Ortec Maestro or Amptek MCA-8000
Pulse-shape analysis :
- Oscilloscope Tektronix TDS3054B
- Off-line Digital filtering: Trapezoidal finite-impulse algorithm
Not used for APDs but providing the best results for PMT!
Experimental setup
Test at Genp-Lab (USC)
Test at Genp-Lab (USC)
APD gain vs. Bias Voltage
5 cm length
The energy resoltution depends on the APD gain and the Bias Voltage
~380V Dgain/DV= 2.84 %
The energy resoltution shows a minimum when The APD Bias Voltage=380
Dependence on shapping time
For small crystals 4ms is a good compromise between energy-resolution and pile-up
Dependence on the acquisition time
Best results achieved for acquisition times between 30-60 s
These curves conatin two effects: statistics and bias voltage drift.
Could be solved by controling Temperature and Bias Voltage
Dependence on Amplifier Gain
Energy resolution improves by increasing the amplifier gain
Best results
Study of the non-uniformity
Energy resolution dependence on the first interaction point
Non-uniformity ~ 8.4 %, to compare with < 3% measured by St. Gobain
Light collection uniformity CMS CAL
P. Sempere PhD Thesis
CsI(Tl) Resolution
R3B/EXL meeting Milan Oct-06
Energy resolution improves for increasing energy
CsI(Tl) with a 60Co source
(1171 keV) and (1332 keV)
Some conclusions
• Several test (wrapping, optical coupling,amplifier gain, shapping time) have been performed to optimise the energy resolution of CsI(Tl)
•APDs from API showed the best energy resolution for CsI(Tl) crystals•APDs S8664-1010 from Hamamatsu showed a very good energy resolution almost independent on the crysal size
• The main drawback of APDs vs PMT is the strong dependence of the gain with Temperature and Bias Voltage
How to improve the resolution:
-Better stabilisation of both temperature and bias-voltage.- Better optical coupling --> Scionix- Surface coating --> Ukranian Institute for Crystals
- New generation of scintillating crystals
T and V dependence
Both Crystals and APDs response depends on Tº
T must be kept very stable ! ~0.1o
otherwise, T should be accurately measured in order to keep gain constant by controlling the bias voltage
Characterization of S8664-1010 APD
T. Ikagawa et al., NIM A 538(2995) 640
T stabilisation ~0.1ºC keep the gain variarion ~ 0.3%
Temperature stabilisation
Refrigerator 4-5 º C
Humidity control box < 30% (1%)
radiator
Resistor warm focusT probe T stable within 0.1ºC
Ceramics Cold focus~ 10ºC
T controller
22ºC
Allow pulse shape analysis with Tektronix TDS3054B
Crystal type-2 Bi-frustrum shaped
Waiting for an agreement with StGobain and IMP- Lanzhou(China) --> Price drop!
Exit face fits to LAAPD S8664-2010 under negotiation
First prototypes done at Lanzhou (China
Further tests through prototype
• Good results are only achieved when there is a perfect matching between the crystal exit surface and the APD entrance area
Type 2 View of the Barrel
average dimensions
3x1x13 cm
Study of St. Gobain vs IMP Lanzhou crystals
Tests performed with API APD Crystal dimensions 1x1x1 cm
Very similar behaviour
Resolution achieved
IMP Lanzhou St. Gobain
R3B Type Crystal
Uniformity of the crystal
Wrapped with ESR (from 3M), tested with 60Co
0 2 4 6 8 10 12 14 16 18 201500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500
Rel
ativ
e Li
ght-
out(
arbi
trar
y U
its)
CsI Position
The light-out uniformity is 2.8%