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This study delves into the decomposition of pile-up pulses, pulse identification through fitting methods, statistics, efficiency, and residual analysis. It explores the Pad Response Function, smearing effects, and experimental measurements. Various algorithms for pulse identification and shape parameterization are discussed, along with the analysis of single pulse, shoulder pulse, and failed fitting scenarios. Additionally, the study looks into pulse separation, efficiency percentages, and the impact of smearing effects on the Pad Response Function.
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TPC Meeting Institute of Physics, Academia Sinica Jia-Ye Chen 2007.6.21
Outline • Pile-up Pulse Decomposition Study • Pulse Identification, Fitting (Well & Failure) • Statistics, Efficiency, Residual and Further more ... • Pad Response Function (PRF) • Smearing Effect and Parameterization of PRF • Experimental Measurement & Analysis
Pile-up Pulse Decompisition • Algorithm for Identification • Single Pulse & Shape Parameterization • Pile-up Pulse, Shoulder Pulse and Coupled • Failed Fitting (small pulse, plateau pulse) • Efficiency : Percentage of Pulse • Residual • Question & Problem
Algorithm for Identification • Pile-up Pulse • peakAdc > threshold (dynamic threshold) • Separation of peakTdc > 2 clocks • Pulse valley away from prevPeakTdc > 2 clocks • Shoulder Pulse ( By Su-Yin Wang ) • Δ(ΔADC ) < -8. • Separation to neighboring peakTdc > 3.
Percentage of Pulse ID • number pileup pulse = 76946 • number of single pulse = 41787 (54.31%) • number of double pulse = 33531 (43.58%) • number of triple pulse = 1294 ( 1.68%) • number of quadruple pulse = 334 ( 0.43%) Pileup GOOD • number of good pulse = 2692664 • number of single pulse = 2198194 (81.64%) • number of double pulse = 484378 (17.99%) • number of triple pulse = 7106 ( 0.26%) • number of quadruple pulse = 2986 ( 0.11%)
Percentage of Failure • number of pileup pulse = 54260 • number of single pulse = 30534 (56.24%) • number of double pulse = 22563 (41.58%) • number of triple pulse = 956 ( 1.76%) • number of quadruple pulse = 247 ( 0.46%) • number of (1) pulse =18 (0.0074%) • (percentage in double pulse (0.0177%)) • (chi_square>4 , single pulse) • number of (1+2+3+4) pulse =89 (0.16%) • (percentage in double pulse (0.39%)) • (chi_square>4 , single pulse)
Efficiency & Residual Run 30501 : First 500 Events & only double-pulse event w/o triple-, quadru-, … NEW 1.5 Events/sec OLD 6 Events/sec
Question & Problem • Can we believe the fitting? • Yes, which should be fitted, which not? • Polynomial Approximation, instead of exact Error Function Fitting? • Computing Time : much slower than previous one.
FWHM of the PRF TRIUMF TPC Pad rows are parallel to the sense wire.
Pad Response Function • Width of PRF • Direct measure of the power to distinguish between two close-by coordinates. • Determine the two-track resolution. The induced charge distribution is called “Pad Response Function”.
Parameterization of PRF Under the optimal design of pad width G : the distance between sense wire and cathode plane : chamber-specific pad response width, often normalized to the pad width ΔP by
Smearing Effects to PRF • The transverse diffusion • The angular wire effect • The angle under which the tracks cross the wire-normal. • The E × B effect close to the sense wires • The angular pad effect • If tracks cross the normal on a pad-row under a non-zero angle. • If more than one wire contributes to a pad signal.
Experimental Measurement New TPC Line Fitting (Lab. Frame) By Nakatsugawa Yohei