Test dependency of the Cerenkov photons collection efficiency with. Impact point of the incoming particle in the radiator. Radiator wrapping material (Al, Tyvek).
GEANT4 Applications for Astroparticles Experiments Maria Catarina Espírito-Santo, Patricia Gonçalves, Mario Pimenta, Pedro Rodrigues, Bernardo Tomé, Andreia Trindade LIP – Lisboa
IEEE NSS/MIC 2003 Conference Detector Simulation and Reconstruction - II 19-25 October 2003
GEANT4 Space Applications Development of GEANT4-based radiation interaction simulations One year project initiated under a ESA/ESTEC contract Radiation Interaction Simulation for High-Energy Astrophysics Experiments EUSO and AMS ESA/ESTEC Contract No 17097/03/NL/LvH/bj
ISS High-Energy astrophysics experiments EUSO/ULTRA (UV Light Transmission and Reflection in the Atmosphere) experiment AMS/RICH (Ring Imaging CHerenkov) sub-detector
P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
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Simulation Framework Overview Simulation requirements • • • •
Simulation of different AMS and EUSO related detector geometries Interface with alternative sets of primary event generators Simulation of readout electronics, signal digitisation and event reconstruction OO-technology for event data persistency and data analysis
Radiation transport: GEANT4 toolkit Signal digitization: DIGITsim Analysis: ROOT Event storage: ROOT I/O CVS code management system
P. Rodrigues, LIP
ROOT Analysis GEANT4
DIGITsim
ROOT I/O CVS Code Management IEEE NSS/MIC 2003, 23 October 2003
3
EUSO in the International Space Station (ISS) EUSO is the first Space mission devoted to the investigation of cosmic rays and neutrinos of extreme energy (E > 5 x 10 19 eV) Phase-A study now complete
EUSO will be deployed to the ISS in 2009/2010 Attached to the European Module Columbus for a 3-year period
P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
4
EUSO – Extreme Universe Space Observatory Extensive Air Showers (EAS) detection • UV fluorescence photons from the de-excitation of N2 molecules isotropically produced along the shower • Cherenkov photons collimated with the shower and reflected/diffused in Earth surface
EECR reconstruction • Fluorescence yield Û shower size • X,Y, time provide shower direction • Z is given by the impact point of the Cherenkov beam
P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
5
ULTRA Support Experiment UV Light Transmission and Reflection in the Atmosphere • Measurement of reflection/diffusion signal due to the EAS Cherenkov impacting in the Earth surface
UVscope
GPS
LIDAR D.Lebrun
• Atmospheric transmission • Albedo of different surfaces (ground, water)
P. Rodrigues, LIP
Runs in Mont-Cenis 2002/03
Runs in Mont-Cenis 2002/03
ETscope
INFN-Palermo INFN-Torino LIP-Lisboa ISN-Grenoble IEEE NSS/MIC 2003, 23 October 2003
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ULTRA Simulation Components 5. Time sampling, analog to digital conversion
4. Signal shaping and amplification
3.Photoelectron production and signal generation
AMP
ADC
Raw Data Generation
PMT
DIGITsimDataFrame 2. Light propagation and collection
1. Energy deposition in the scintillator, photon generation
GEANT4Space Application P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
7
GEANT4 ETscope Simulation Characterization of detector response • Scintillator NE102A (10 000 photons/MeV) • Internal walls coated with diffusive paint • Optical boundaries: G4 UNIFIED model
The scintillator emission spectrum was included in the simulation as an optic material property P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
8
Deposited Energy (MeV)
ETscope Simulation – Sample Results 80 MeV electron
# Outgoing Photons
Source Position (cm)
80 MeV electron
Optical Photons Collection efficiency Source Position (cm)
P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
9
ETscope Hits Digitization Simulation of LIP–PAD PCI card • 6 channels 10-bit ADC@100 MHz • 8 time samples, voltage range 0-1 V
Production of information digitized with DIGITsim • Input: GEANT4 hit collections • Output: digitized information of the hit collections • To be reconstructed with the same algorithms for experimental data
Preliminary implementation • Energy deposited in the scintillator used to obtain the total collected charge ecoll @ 0.10, eQE @ 0.15, eacc @ 1.0, G @ 5.106, Amplifier Gain = 50 V/A
Q = Edep × Y × e coll × e QE × e acc × G
• Observed ULTRA station pulse shape taken into account:
D @ 8 ns, w = 1 Pedestal level set 0 P. Rodrigues, LIP
V (t ) = Vmax × e IEEE NSS/MIC 2003, 23 October 2003
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1 2 æ t -t 0 ö log ç ÷ 2 w2 è D ø
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ETscope Pulse Digitization Preliminary
Preliminary
To be included: Explicit description of the conversion of the optical photons at the PMTs photocatode More accurate information about the pulse shape at the amplification stage Reconstruction in DIGITsimReconstruction with analysis code used in ULTRA test runs and comparison with data P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
11
AMS – Alpha Magnetic Spectrometer AMS objectives Characterisation of cosmic rays before reaching the Earth atmosphere Percursor flight (AMS-I) in 1998 aboard the Space Shutle
Radiator
Reflector
AMS/RICH detector Proximity focusing detector with an aerogel radiator for velocity and charge measurement
PMTs
• Number of photons proportional to Z2 • Cerenkov cone opening angle related to the velocity b: cos(qc)=1/(bn). PMTs Structure P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
12
GEANT4 AMS/RICH Simulation Prototype implementation of aerogel RICH radiator • Aerogel tiles (n=1.03) with absorption length 100 cm • Plexiglas foils (n=1.49) below the aerogel tiles Aerogel
Top View
P. Rodrigues, LIP
Plexiglas
Side View
IEEE NSS/MIC 2003, 23 October 2003
13
2003 AMS II RICH Test-Beam Cherenkov Counter To RICH prototype Cherenkov counter
Light guide PMT matrix
Beam
Phototube Independent measurement of charge PMT matrix
October/November test beam CERN SPS Indium 158 GeV/nucleon beam on beryllium target Extraction of beam with constant A/Z A/Z = 1, A/Z =2 (He4 … Z up to 26) , A/Z =3/2 (He3) P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
14
GEANT4 AMS II RICH Test-Beam Simulation 80 GeV electron beam
Preliminary
Number of generated Cerenkov photons
PMMA radiator
Test charge identification as a function of Z Test dependency of the Cerenkov photons collection efficiency with Impact point of the incoming particle in the radiator Radiator wrapping material (Al, Tyvek) P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
15
Next Steps … Proof-of-principle GEANT4 simulation code produced EUSO and ULTRA applications • Simulation of the optics of the ULTRA UV detector • Experimental setup for fluorescence measurements • Cherenkov light in the EUSO Fresnel lenses from space environment radiation
AMS-II RICH Test beam • • • •
Optimize the Cherenkov counter (wrapping and geometry) Comparison with beam test results by the end of October/November Detailed study of the AMS radiator and of light collection Integration in the general AMS scheme
P. Rodrigues, LIP
IEEE NSS/MIC 2003, 23 October 2003
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