Expected Performances of the scintillator counters Time Of Flight system of the AMS-02 experiment

Expected Performances of the scintillator counters Time Of Flight system of the AMS-02 experiment Cristina Sbarra for the AMS-TOF Bologna group (sbarra@bo.infn.it) INFN-Bologna (Italy) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.1/13

Contents The TOF-02 design and mechanics Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.2/13

Contents The TOF-02 design and mechanics The fine mesh PMs and their displacement on the TOF-02 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.2/13

Contents The TOF-02 design and mechanics The fine mesh PMs and their displacement on the TOF-02 The TOF-02 counters and the space qualification tests Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.2/13

Contents The TOF-02 design and mechanics The fine mesh PMs and their displacement on the TOF-02 The TOF-02 counters and the space qualification tests Trigger acceptance Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.2/13

Contents The TOF-02 design and mechanics The fine mesh PMs and their displacement on the TOF-02 The TOF-02 counters and the space qualification tests Trigger acceptance Beam test results Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.2/13

The requirements for the TOF the fast trigger to the whole experiment; measurement of the CR time of flight with a resolution to distinguish upward from downward going particles at a level of 10 9 level, and electrons from antiprotons at low momentum; the measurement of the absolute charge in addition to the measurement done by the tracker and the rich. Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.3/13

The TOF-02 design and mechanics geometrical acceptance fixed => 0.4 m 2 sr Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.4/13

The TOF-02 design and mechanics geometrical acceptance fixed => 0.4 m 2 sr 4 planes, each covering a circular area of 1.2 m 2 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.4/13

The TOF-02 design and mechanics geometrical acceptance fixed => 0.4 m 2 sr 4 planes, each covering a circular area of 1.2 m 2 12 cm wide scintillators pads for plane (0.5 cm overlapped) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.4/13

The TOF-02 design and mechanics geometrical acceptance fixed => 0.4 m 2 sr 4 planes, each covering a circular area of 1.2 m 2 12 cm wide scintillators pads for plane (0.5 cm overlapped) to minimize the angle between the PM axis and B => curved and twisted light guides Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.4/13

The TOF-02 design and mechanics PMs Conical light guides Curved light guides Scintillator Clear plastic Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.5/13

The TOF-02 design and mechanics upper (left) and lower (right) TOF planes Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.5/13

The TOF-02 design and mechanics An exploded view of the complete TOF structure Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.5/13

The Fine Mesh PMs Hamamatsu R5946 bialkali photocathode 16 bialkali mesh dynodes max spectral response at 450nm (QE 20%) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.6/13

The Fine Mesh PMs magnetic field effect on PM response Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.6/13

The Fine Mesh PMs magnetic field effect on time response Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.6/13

The Fine Mesh PMs: work done 195 fine mesh PMs calibrated in 2003 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.7/13

The Fine Mesh PMs: work done 195 fine mesh PMs calibrated in 2003 PMs classified with respect to their working HV ( HV to have G = 1 10 6 ) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.7/13

The Fine Mesh PMs: work done 195 fine mesh PMs calibrated in 2003 PMs classified with respect to their working HV ( HV to have G = 1 10 6 ) a genetic alghorithm has been used to displace the calibrated PMs in the TOF-02 structure, using the working HV calculated and other measurements previously made in the magnetic field (<- ICRC 2001). Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.7/13

The Fine Mesh PMs: work done 195 fine mesh PMs calibrated in 2003 PMs classified with respect to their working HV ( HV to have G = 1 10 6 ) a genetic alghorithm has been used to displace the calibrated PMs in the TOF-02 structure, using the working HV calculated and other measurements previously made in the magnetic field (<- ICRC 2001). calibration results and PMs displacement are on line (http://ams.bo.infn.it/database) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.7/13

Counters and space qualification tests The TOF-02 counters are being characterized in the INFN laboratories of Bologna with a Cosmic Rays telescope in order to find: Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.8/13

Counters and space qualification tests The TOF-02 counters are being characterized in the INFN laboratories of Bologna with a Cosmic Rays telescope in order to find: Attenuation Lenght V light in the counter Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.8/13

Counters and space qualification tests The TOF-02 counters are being characterized in the INFN laboratories of Bologna with a Cosmic Rays telescope in order to find: Attenuation Lenght V light in the counter Photostatistics (N. of photons in the center ) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.8/13

Counters and space qualification tests The TOF-02 counters are being characterized in the INFN laboratories of Bologna with a Cosmic Rays telescope in order to find: Attenuation Lenght V light in the counter Photostatistics (N. of photons in the center ) Intrinsic time resolution (count. sides time difference) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.8/13

Counters and space qualification tests The TOF-02 counters are being characterized in the INFN laboratories of Bologna with a Cosmic Rays telescope in order to find: Attenuation Lenght V light in the counter Photostatistics (N. of photons in the center ) Intrinsic time resolution (count. sides time difference) Time of flight resolution (count. - ref. time difference) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.8/13

Counters and space qualification tests The TOF-02 must be able to operate in space for three years and must substain the acceleration of the launch, thus it must undergo several thermal-vacuum and mechanical tests: Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.9/13

Counters and space qualification tests The TOF-02 must be able to operate in space for three years and must substain the acceleration of the launch, thus it must undergo several thermal-vacuum and mechanical tests: A group of 10 PMs was tested in the simulator for dark curr and pulse height meas. (=> see the poster C) A complete counter was also tested Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.9/13

Counters and space qualification tests The TOF-02 must be able to operate in space for three years and must substain the acceleration of the launch, thus it must undergo several thermal-vacuum and mechanical tests: A group of 10 PMs was tested in the simulator for dark curr and pulse height meas. (=> see the poster C) A complete counter was also tested Results are encouraging Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.9/13

Counters and space qualification tests Counter characterization before and after test Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.10/13

Counters and space qualification tests Counter characterization before and after test => Results are the same bef.: L n = 177 cm, L p = 156 cm after: L n = 176 cm, L p = 154 cm error: ± 1 2% Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.10/13

Counters and space qualification tests Counter characterization before and after test => Results are the same bef.: L n = 177 cm, L p = 156 cm after: L n = 176 cm, L p = 154 cm error: ± 1 2% =>counter beared the test AMS-BO internal notes - http://ams.bo.infn.it/notes Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.10/13

Trigger efficiency The FT is generated when 3/4 TOF planes signals above a Threshold Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.11/13

Trigger efficiency The FT is generated when 3/4 TOF planes signals above a Threshold The TOF flags CRs with Z > 1 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.11/13

Trigger efficiency The FT is generated when 3/4 TOF planes signals above a Threshold The TOF flags CRs with Z > 1 A threshold of 3.5 mip can suppress 99% of the protons without affecting eavier ions efficiency efficiency 1 10 10 10 1 2 3 p, cut on side p, cut on sum He, cut on side He, cut on sum Li, cut on side Li, cut on sum 0 2 4 6 8 10 12 14 16 18 2 cut (m.i.p.) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.11/13

Beam test results Four TOF scintillators were used during ion test beam at CERN 2003 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.12/13

Beam test results Four TOF scintillators were used during ion test beam at CERN 2003 the two worst counters for guides: C2 and C3 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.12/13

Beam test results Four TOF scintillators were used during ion test beam at CERN 2003 10 4 He Entries 67418 Ion charge is well measured by all counters 10 10 3 2 H 2p Li Be B C N O F Ne Na Mg Al 10 5 10 15 20 25 30 35 40 45 C2 left anode, sqrt(adc) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.12/13

Beam test results Four TOF scintillators were used during ion test beam at CERN 2003 σ Z 0.4 0.3 P1 0.4805E 01 0.1393E 02 P2 0.2630E 01 0.6542E 03 0.2 charge resolution for anodes and dynodes is computed σ Z 0.1 0 0 2 4 6 8 10 Z C2AR 12 0.5 0.4 0.3 P1 P2 0.8314E 01 0.1467E 02 0.2116E 01 0.6830E 03 0.2 0.1 0 2 4 6 8 10 Z C2DR 12 Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.12/13

Beam test results Four TOF scintillators were used during ion test beam at CERN 2003 Z TOF 30 ENTRIES 21512 the TOF data are compared with RICH measurements 25 20 15 10 10 2 10 5 1 0 0 5 10 15 20 25 30 Z RICH Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.12/13

Conclusions With the TOF design and the phototubes characterization the fine mesh PMs were displaced in the structure Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.13/13

Conclusions With the TOF design and the phototubes characterization the fine mesh PMs were displaced in the structure The TOF system can operate from 40 to +50 Celsius without major problems Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.13/13

Conclusions With the TOF design and the phototubes characterization the fine mesh PMs were displaced in the structure The TOF system can operate from 40 to +50 Celsius without major problems The trigger acceptance allows to suppress 99% of the proton flux at level-1 trigger Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.13/13

Conclusions With the TOF design and the phototubes characterization the fine mesh PMs were displaced in the structure The TOF system can operate from 40 to +50 Celsius without major problems The trigger acceptance allows to suppress 99% of the proton flux at level-1 trigger From the last beam test results it can be inferred a counter intr. time res. of 150 ps (TOF web page http://ams.bo.infn.it/ ) Cristina Sbarra INFN-Bologna http://ams.bo.infn.it p.13/13