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A Study of Time over Threshold (TOT) Technique for Plastic Scintillator Counter. 高能物理研究所 吴金杰. Outline. Introduction Research method-wave analysis Signal characteristics Relative charge resolution by TOT Summary. Introduction to TOT (1). TOT - T ime O ver T hreshold Pulse width
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A Study of Time over Threshold (TOT) Techniquefor Plastic Scintillator Counter 高能物理研究所 吴金杰
Outline • Introduction • Research method-wave analysis • Signal characteristics • Relative charge resolution by TOT • Summary
Introduction to TOT (1) • TOT-Time Over Threshold • Pulse width • TOT is somewhat dependent the charge • Different threshold • Advantage: • One of alternatives to charge measurement • Simplify the electronics • Reduce the cost Time over threshold
Introduction to TOT (2) • Apply in gas detectors • Multi-gap Resistive Plate Chamber of ALICE and STAR: • NINO-Correction of front edge time walk • Drift Chamber of CLEO-III: • Relative charge resolution: 10% • TOT for Plastic scintillator counter? • The correlation between TOT and Charge? • Relative charge resolution? TOT versus measured time Relative Charge resolution of CLEO
Research method-wave analysis • To be measure TOT, Amplitude, Charge • How? • Chip? • Based on CAMAC system? • Wave analysis • Using high quality oscilloscope sample rate 20 GS/s • TOF module Scintillator EJ200 +R5924 Experimental setup
Pedestal, Noise, Rise time • The data within the first 250 ns are noise without any particle passing through the scintillator counter • Noise: 2.0 mV • Pedestal: 2.2 mV • Rise time:4.2ns A wave shape of pulse Reference to the design BESIII TOF electronics The noise spectrum Spectrum of rise time
Amplitude, Charge The charge is obtained from the time integral of the current pulse Spectrum of charge Spectrum of amplitude Charge versus amplitude
Distribution of TOT The distribution of TOT with different threshold The distribution of TOT when the threshold is set to 65 mV 15% of the most probable value of amplitude The distribution of TOT when the threshold is set to 195 mV 45% of the most probable value of amplitude
TOT VS Charge--threshold 65mV Linear correlation between TOT and charge Relative charge resolution can reach 7%-18% when the threshold is set to 65mV TOT versus charge The relative error of Q by TOT can be obtained by formula The relative charge resolution versus charge
TOT VS Charge--threshold 195mV The correlation between TOT and charge TOT versus charge Relative charge resolution can reach 4%-7% when the threshold is set to 195mV The relative charge resolution versus charge
Summary • A Study of TOT technique for Scintillator counter firstly • Wave analysis • The Characteristics of TOF module Pedestal, Noise, Amplitude, Charge, Rise time • Relative charge resolution From 7% to 18% (Threshold is set to 65mv) From 4% to 7% (Threshold is set to 195mv)