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PAUL SCHERRER INSTITUT. TEST OF BC400 SCINTILLATOR RESPONSE TO GAMMA AND BETA SOURCES. W. Hajdas, E. Suarez-Garcia, K. Egli, A. Mtchedlishvili PSI, Villigen, CH. Kick-off, 4 Apr 2007. PAUL SCHERRER INSTITUT. Scintillators. 70 BC400 bars (5.8x5.8x200) delivered from St.Gobain
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PAUL SCHERRER INSTITUT TEST OF BC400 SCINTILLATOR RESPONSE TO GAMMA AND BETA SOURCES W. Hajdas, E. Suarez-Garcia, K. Egli, A. Mtchedlishvili PSI, Villigen, CH Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Scintillators • 70 BC400 bars (5.8x5.8x200) delivered from St.Gobain • Unit price 54 US$, delivery time 2.5 months • Very good quality and small STD for dimension differences • Teflon and Alu coating as well as no coating tests of linearity • Surface quality test with Profile-meter from NanoLab (see Estela talk) • Two pieces to IBJ(PL) for polishing and tests (see Radek talk) Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Scintillators Teflon and Alu Coated BC400 plastic scintillators (5.8x5.8x200 mm3) Kick-off, 4 Apr 2007
BC400 Plastic Fast Discriminator Gate Linear Integrator PC +MCA H8500MAPMT X10 Fast Amplifier Delay High Voltage PAUL SCHERRER INSTITUT Readout Electronics Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Readout Electronics Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Test Setup ‘Dark chamber’ with 64 outputsand HV input H8500 MAPMT with rails for source handler Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Scintillator and Source Mounting Source leather mount on the rail in front of BC400 Single BC400 arranged on H8500(optical fat coupling) Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Scintillator and Source Mounting Source in holder on top;chamber view from above Source in the middle position on the leather Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Measurements • Runs with following sources: • 90Sr (beta) • 241Am (gamma, 60 keV) • 57Co (gamma, 122 keV) • Positions along scintillator bar: low (close to PM), middle, high • Measurement: Beta-spectrum maximum position Compton edge (ev. with Photopeak) extrapolated range • Coating for BC400: Al (2), Teflon (2) and no Coating • Two Anodes: Nr 64 and Nr 8) • High Voltage V= 1000 V and 1050 V Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Spectra – 90Sr and 241Am Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Spectra – Signal and Background Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Spectra – Low and High Source Location Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Method I - Maximum Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Method II - Extrapolation Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Results 90Sr, Al and Teflon Coating, 4 bars Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Results 90Sr, No Coating and Anode Nr 8 Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Results 241Am, Al and Teflon Coating, 4 bars Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Results 241Am HV and 57Co Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Results Summary • Mean High vs. Low Shift for Al = 10% (results from both Sr, Am sources) • Mean High vs. Low Shift for Teflon = 10% • Mean High vs. Low Shift for no Coating = 18% (results from 1 bar only) • Mean Middle vs. Low Shift for Al+Teflon = 2% • Mean Shift from 90Sr source = 8% • Mean Shift from 241Am+57Co sources = 15% • (single worst result for one data point = 43%, Chi2 = 2.) Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Conclusions • Coating thickness for beta and background for gamma – error sources • Light Output reduction along BC400 bar is small (10%) • Data confirms Monte Carlo results with Optical Photons • Polishing quality of BC400 from factory is already satisfactory • No need for wavelength shifters • Trade: further polishing vs. bar width distribution straggling Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Extra: Test with Big Plastic and 90Sr Kick-off, 4 Apr 2007
PAUL SCHERRER INSTITUT Extra: Max Shift in Al Foils for 90Sr Kick-off, 4 Apr 2007