Simulation and modeling of BEGe detectors Matteo Agostini, Calin A. Ur, E. Bellotti, D. Budj´ aˇ s, C. Cattadori, A. di Vacri, A. Garfagnini, L. Pandola, S. Sch¨ onert Max-Plank-Institute f¨ ur Kernphysik MaGe meeting, January 18th 2010 Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 1
Outline The BEGe detectors 1 The simulation 2 The structure of the simulation Design and implementation of the simulation Validation of the simulation 3 Validation of the MaGe simulation Validation of the PSS Conclusion 4 Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 2
The BEGe detectors The BEGe geometry Al endcap thick-window BEGe 71 mm PRE n+ contact 3500 V 31 mm p-type Ge groove p+ contact (read–out electrode) N 2 0 V Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 3
The BEGe detectors The (LNGS) BEGe features 10 5 10 6 1.607 keV analogue digital 10 4 10 5 10 3 10 2 Electrical Characteristics: 10 4 10 1 counts Depletion voltage +3000 V 1100 1173 1250 1332 10 3 Operational bias voltage +3500 V Integral nonlinearity < 0 . 05% 10 2 Physical Characteristics: 10 1 Active diameter 71 mm 500 1000 1500 2000 2500 3800 mm 2 Active area Energy [keV] Thickness 32 mm 2.4 Distance from window 5 mm analogue 2.2 digital Efficiency > 34% 2 FWHM [keV] 1.8 Energy Resolution at 1332 . 5 keV : 1.6 1.4 FWHM (nominal) 1 . 752 keV fitting function: 1.2 f ( x ) = √ 0 . 31 + 0 . 0018 x FWHM (measured) 1 . 607 ± 0 . 003 keV 1 f (0) = √ a ∼ 0 . 55 keV FWTM 3 . 259 keV 0.8 0 500 1000 1500 2000 2500 300 Energy [keV] Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 4
The simulation The structure of the simulation I. MC simulation – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit – > electron and hole trajectories – > the signal induced on the point size electrode III. DAQ simulations < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) – > each pulse is convolved with the PTF – > all the pulses of an event are added up – > the noise is added to the total pulse Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation interaction points anode cathode I. MC simulation – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit – > electron and hole trajectories – > the signal induced on the point size electrode III. DAQ simulations < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) – > each pulse is convolved with the PTF – > all the pulses of an event are added up – > the noise is added to the total pulse Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation anode cathode electrons I. MC simulation holes – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit – > electron and hole trajectories – > the signal induced on the point size electrode III. DAQ simulations < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) – > each pulse is convolved with the PTF – > all the pulses of an event are added up – > the noise is added to the total pulse Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation anode cathode electrons I. MC simulation holes – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit 0.06 – > electron and hole trajectories e pulse h pulse total pulse – > the signal induced on the point size 0.05 electrode 0.04 adc counts 0.03 III. DAQ simulations 0.02 < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) 0.01 – > each pulse is convolved with the PTF 0 – > all the pulses of an event are added up -0.01 0 5e-08 1e-07 1.5e-07 2e-07 2.5e-07 3e-07 3.5e-07 4e-07 4.5e-07 – > the noise is added to the total pulse time [ns] Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation anode cathode electrons I. MC simulation holes – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit 0.06 – > electron and hole trajectories e pulse h pulse total pulse total pulse + pre – > the signal induced on the point size 0.05 electrode 0.04 adc counts 0.03 III. DAQ simulations 0.02 < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) 0.01 – > each pulse is convolved with the PTF 0 – > all the pulses of an event are added up -0.01 0 5e-08 1e-07 1.5e-07 2e-07 2.5e-07 3e-07 3.5e-07 4e-07 4.5e-07 – > the noise is added to the total pulse time [ns] Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation anode cathode electrons I. MC simulation holes – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit 1000 – > electron and hole trajectories 2.0 MeV MSE 1.1 MeV SSE (28,34,16) 0.4 MeV SSE (46,34,26) 0.5 MeV SSE (66,34,26) – > the signal induced on the point size 800 electrode 600 adc counts [a.u.] III. DAQ simulations 400 < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) 200 – > each pulse is convolved with the PTF – > all the pulses of an event are added up 0 0 1e-07 2e-07 3e-07 4e-07 5e-07 6e-07 7e-07 8e-07 9e-07 – > the noise is added to the total pulse time [s] Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The structure of the simulation anode cathode electrons I. MC simulation holes – > coordinates and energy of the hits II. Signal formation and development < – coordinate of each hit 1000 – > electron and hole trajectories 2.0 MeV MSE 1.1 MeV SSE (28,34,16) 0.4 MeV SSE (46,34,26) 0.5 MeV SSE (66,34,26) – > the signal induced on the point size 800 electrode 600 adc counts [a.u.] III. DAQ simulations 400 < – energy and signal for each hit in an event < – the Preamplifier Transfer Function (PTF) 200 – > each pulse is convolved with the PTF – > all the pulses of an event are added up 0 0 1e-07 2e-07 3e-07 4e-07 5e-07 6e-07 7e-07 8e-07 9e-07 – > the noise is added to the total pulse time [s] Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 5
The simulation The simulation design step 0. Create a library of pulses: 0.1 divide the detector in cubic cell (1 mm × 1 mm × 1 mm) and generate a pulse for each cell 0.2 convolve each pulse with the PTF 0.3 store all the pulses in a library step 1. Run the MC simulation step 2. For each hit compute the pulse as weighted average of the pulses stored in the library step 3. For each event compute the total pulse by adding up the pulse of each hit step 4. Add the noise Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 6
The simulation The simulation design step 0. Create a library of pulses: 0.1 divide the detector in cubic cell (1 mm × 1 mm × 1 mm) < – MGS and generate a pulse for each cell 0.2 convolve each pulse with the PTF 0.3 store all the pulses in a library step 1. Run the MC simulation step 2. For each hit compute the pulse as weighted average of the pulses stored in the library step 3. For each event compute the total pulse by adding up the pulse of each hit step 4. Add the noise MGS v 5r02 : Multi Geometry Simulation is a MATLAB software developed for the AGATA project ( http://www.iphc.cnrs.fr/-MGS-.html ) Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 6
The simulation The simulation design step 0. Create a library of pulses: 0.1 divide the detector in cubic cell (1 mm × 1 mm × 1 mm) < – MGS and generate a pulse for each cell 0.2 convolve each pulse with the PTF 0.3 store all the pulses in a library < – MaGe step 1. Run the MC simulation step 2. For each hit compute the pulse as weighted average of the pulses stored in the library step 3. For each event compute the total pulse by adding up the pulse of each hit step 4. Add the noise MGS v 5r02 : Multi Geometry Simulation is a MATLAB software developed for the AGATA project ( http://www.iphc.cnrs.fr/-MGS-.html ) MaGe: BEGe geometry used munichteststand/GELNGSBEGeDetector.hh Simulation and modeling of BEGe detectors Matteo Agostini (MPIK) 6
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