measurement of 'intrinsic' properties of scintillating fibers
DESCRIPTION
Measurement of 'intrinsic' properties of scintillating fibers. H. Sakamoto Osaka University, Japan Sato M. Yoshida Y. Kuno Osaka Univ. K. Yoshimura KEK. Purpose. To optimize a concentration of the secondary dopant (3HF) for scintillating fibers - PowerPoint PPT PresentationTRANSCRIPT
Measurement of 'intrinsic' properties
of scintillating fibers
H. Sakamoto Osaka University, Japan
A. Sato M. Yoshida Y. Kuno Osaka Univ.K. Yoshimura KEK
Purpose
To optimize a concentration of the secondary dopant (3HF) for scintillating fibers KEK beam test to study light yields & cross talk for some different concentration
Attenuation length of a clear fiber Light yield loss
Summary
Beam test @ KEK
To study the light yields and cross talk of 3HF concentration dependence
Scintillating fibers tested: Kuraray SCSF-3HF ; 350um-phi, multi-clad, s-type
Primary (pT) + Secondary (3HF;5000ppm) Primary (pT) + Secondary (3HF;3500ppm) Primary (pT) + Secondary (3HF;2500ppm) No primary + Secondary (3HF;5000ppm)
KEK beam test set up Ⅰ
D1 TOF2D2Sci-Fi
Trigger coincidence of all counters and Sci-Fi
Data we took ADC & TDC of all counters and Sci-Fi
3m0.5m5m
•600MeV/c•700MeV/c•1Gev/c
TOF2 Sci-Fi TOF1D1
Dark box
D2
• p+ •π+ •μ+
Beam
Beam line
Sci-Fi in Dark box
D1
D2 TOF2
KEK beam test set up Ⅱ
3HF emission spectrum & Q.E. of VLPC
3HF emission spectrum
520nm
Quantum efficiency of VLPC
520nm
Photo multiplier tube
We used the photo multiplier tube instead of VLPC.
Hamamatsu R7899MOD Extended Green
Photocathode 1 inch diameter 10 stage Head-on Type Prismatic Window HV= -1800V
Set up of scintillating fiber•Side view
PMTSci-Fi
Aluminized tape
22mm
20 fibers
These were in a dark box
•Front view
PMTSci-fi
Analysis
Average number of photo electron was estimated by fitting the sci-fi ADC spectrum to a poisson distribution.
typical sci-fi ADC spectrum
Adc count
count
Result of light yield
5000ppm has the highest light yield in tested fibers (2.6p.e.@MIP).
Light yield of 3HF concentration dependence
Ave.
# o
f p.
e.
dE/d x (MeV/cm)
5000ppm3500ppm2500ppm
Only 5000ppm
350um phi
Set up for cross talk test
The differences A & B of light yield result in cross talk
•Black papers between every fiber
•Tie together every two fibers •Put black papers in between
A
B
Result of cross talk test
Cross talk Ave. # of p.e.@MIP (2.0 MeV/cm)
5000ppm 3500ppm 2500ppmOnly 5000ppm
Set up A 2.60 2.24 2.24 1.86
Set up B 2.78 2.37 2.31 2.00
(B-A) /A 7% 6% 3% 8%
No evidence of cross talk
If cross talk small large
very small
Conclusion from the beam test
We tested scintillating fibers of different 3HF concentration.
We used green sensitive PMTs in stead of VLPC.
The result of light yield test 5000ppm has the highest light yield of 2.6 p.e. @ MIP.
The result of cross talk test No evidence of cross talk can be seen.
Atte. length of clear fiber Ⅰ
Set up Clear fiber: KURARAY CLEAR-PS
Round, Multi-Clad, S-type Pulser:
Duration: 1nsec Period: 10msec Pulse height: -5.5V
Silicon photo diode ORIEL Model 70313
Atte. length of clear fiber Ⅱ Fitting
F=exp(A-x/L1)+exp(B-x/L2) Result
A =1.49 B =0.32 L1=7.62 L2=0.69
Attenuation Length is 7.62m.
Our waveguide of prototype is 4m clear fiber
40% loss was estimated
KURARAY CLEAR-PS 1.05mmphi, Multi-Clad, S-type, Round
Summary
We studied the light yield and cross talk of scintillation fibers mixed with 3HF as a secondary dopant.
Scintillating fibers tested : Kuraray SCSF-3HF pT+5000ppm, pT+3500ppm, pT+2500ppm, only5000ppm Light yield : pT+5000ppm has the highest light yield of 2.6 [email protected]. Cross talk : No evidence of cross talk can be seen.
We also studied the attenuation length of the clear fiber. 40% loss was estimated in 4m (in the prototype)