Pad Response Function Nuclear Physics Group Institute of Physics, Academia Sinica Jia-Ye Chen 2006.8.11

Nuclear Physics Group Meeting, IPAS Outline Time Projection Chamber Pad Response Function (PRF) Smearing Effect to PRF Parameterization of PRF Experimental Measurement Analysis Future Work 2006.8.11 Nuclear Physics Group Meeting, IPAS

Time Projection Chamber The Time Projection Chamber, T. Lohse and W. Witzeling, C.E.R.N. 2006.8.11 Nuclear Physics Group Meeting, IPAS

Electric Field Lines with the Gate 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS TPC Gating Modes Drift Velocity Drift Volume Length ~ Clock ~ 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS Gate Wire 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS FADC Pulses 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS 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”. 2006.8.11 Nuclear Physics Group Meeting, IPAS

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 2006.8.11 Nuclear Physics Group Meeting, IPAS

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. 2006.8.11 Nuclear Physics Group Meeting, IPAS

Smearing Effects to PRF transverse diffusion coefficient drift velocity of electron drift length wire spacing Lorentz angle due to ExB effect 2006.8.11 Nuclear Physics Group Meeting, IPAS

Experimental Measurement New TPC Line Fitting (Lab. Frame) By Nakatsugawa Yohei 2006.8.11 Nuclear Physics Group Meeting, IPAS

With & W/O Normalized ADC X(mm) ADC 2D Histogram 2D Profile Normalized W/O Normalized Why normalized? Uniform sum of ADCs. Smooth the spikes. Eliminate the saturation of ADC. Pulse1 : peakADC1 Pulse2 : peakADC2 Pulse3 : peakADC3 Normalize to sum of three peakADCs. → peakADC?/sumPeakADC 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS 2D Histogram Slices = Normalized W/O Normalized 2006.8.11 Nuclear Physics Group Meeting, IPAS

Drift Length Dependence 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS FWHM of the PRF TRIUMF TPC Pad rows are parallel to the sense wire. 2006.8.11 Nuclear Physics Group Meeting, IPAS

Angular Wire Dependence Pad Response Width Angle (track,wire) 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS Angle(pad,wire) From layer 1 to 13, total 986 pads. 2006.8.11 Nuclear Physics Group Meeting, IPAS

Coupled Geometry Dependence 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS Simulation to PRF 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS What I ever tried Layer Dependence → Pad size dependence Charge Dependence → No dependence With E×B Effect → Ntuples can NOT be used to study PRF Drift Length Dependence → Small Dependence 2006.8.11 Nuclear Physics Group Meeting, IPAS

Nuclear Physics Group Meeting, IPAS Future Work Check drift length dependence again. Normalize PRF simulation. By 2D fitting to PRF, to get the transverse diffusion coefficient DT. 2006.8.11 Nuclear Physics Group Meeting, IPAS