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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
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Measurement of 'intrinsic' propertiesof 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 • 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)
TOF2 TOF1 Sci-Fi D2 D1 Beam • p+ • π+ • μ+ • 600MeV/c • 700MeV/c • 1Gev/c Dark box 0.5m 5m 3m KEK beam test set up Ⅰ • Trigger • coincidence of all counters and Sci-Fi • Data we took • ADC & TDC of all counters and Sci-Fi Sci-Fi TOF2 D1 D2
KEK beam test set up Ⅱ Sci-Fi in Dark box D2 TOF2 Beam line D1
Quantum efficiency of VLPC • 3HF emission spectrum 520nm 520nm 3HF emission spectrum & Q.E. of VLPC
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
22mm 20 fibers Aluminized tape Set up of scintillating fiber • Side view • Front view Sci-Fi PMT PMT Sci-fi • These were in a dark box
count Adc count Analysis • Average number of photo electron was estimated by fitting the sci-fi ADC spectrum • to a poisson distribution. • typical sci-fi ADC spectrum
350um phi Ave. # of p.e. 5000ppm 3500ppm 2500ppm Only 5000ppm dE/dx(MeV/cm) Result of light yield • Light yield of 3HF concentration dependence • 5000ppm has the highest lightyield in tested fibers (2.6p.e.@MIP).
Tie together every two fibers • Put black papers in between Set up for cross talk test • The differences A & B of light yield result in cross talk A • Black papers between every fiber B
Result of cross talk test • Cross talk • Ave. # of p.e.@MIP (2.0 MeV/cm) • No evidence of cross talk
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 • 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 • Fitting • F=exp(A-x/L1)+exp(B-x/L2) 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+5000ppmhas the highest light yield of 2.6 p.e.@M.I.P. • 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)