AMS2: Alpha Magnetic Spectrometer

Collaboration:

- Italy: INFN Bologna, Milano, Perugia, Pisa, Roma I, Siena, Trieste (Italy); Agenzia Spaziale Italiana
- China: Accademia Sinica, CALT, IEE, Shandong Univ.
- Finlandia: HUT, Turku Univ.
- France: ISN, LAPP
- Germany: RWTH I e III, MEPI
- Russia: ITEP, LIP, MEPI, SRI-RAS
- Spain: CIEMAT
- Switzerland: ETH, Geneva Univ.
- USA: Boston Univ., CALTECH, J.Hopkins Univ., MIT, Maryland Univ.

Location of the experiment:Shuttle and International Space Station

National Responsible: R. Battiston (Pg)

1. Goal of the experiment

The disappearance of the antimatter and the presence at all scales in our universe of non-luminous components of matter (dark matter) are the two most intriguing mysteries in our current understanding of the structure of the Universe. To study these problems by measuring with the highest accuracy the composition of Cosmic Rays, a high energy physics experiment, the Alpha Magnetic Spectrometer (AMS) is scheduled for installation on the International Space Station for a three year mission. In preparation for this long duration mission AMS flew a ten days precursor mission on board of the space shuttle Discovery during flight STS-91 in June 1998.

More on the experiment…

2.

Activities during 2002

During this year the construction of the sub-detectors for AMS2 has advanced significantly. A completed ECAL module has been submitted to a test beam at CERN showing design performances. Nearly 40% of the silicon ladders have been produced and two test beam with ions particles have been done using multiple silicon layers. A 1:1 scale RICH prototype has been constructed and submitted to test beam with excellent results in particle identification. Several papers have been published both and journals and conference proceedings, in particular a Physics Report paper summarizing all measurements obtained with STS-91 data. A large effort has been performed to develop the complete AMS-02 thermal system integrating the various subsystems.

The following achievements have been obtained:

- Completion of ECAL Space Qualification Tests in China (100%)
- Completion of ECAL test beam data analysis (100%)
- Start flight modules production (HV, LV, EDR) for ECAL (50%)
- Completion HV divider + FEE ECAL (100%)
- Completion of 192 tracker Silicon Ladders (70%)
- Completion ordering AMS-02 silicon sensors (80%)
- Development of tracker power supplies engineering models (80%)
- Proposal for organization and distribution of AMS-02 data (60%)

Milestones 2003:

Space qualification of the HV and PM system of the ToF | 31-01-2003
Test of a flight model ToF counter | 31-03-2003
Completion of the silicon ladder assembly | 31-08-2003
Completion of the Flight Model ECAL | 31-08-2003
Test of the first half of the Flight Model ToF | 09-09-2003
Completion of the Silicon Tracker integration | 31-12-2003
Porting of data catalog procedure in the Linux+MySql environment | 31-12-2003
Comparison among Oracle and MySql | 30-12-2003
Completion of migration of the system from RAID on HP-UX 10.20 to RAID on Linux | 31-12-2003
Optimization of a unidimensional stocastical model of solar modulation and extension to the bidimensional case | 31-12-2003

3. INFN contribution to the experiment in terms of manpower and financial support:

Manpower: 70 researchers (45 FTE), 15 technicians (6 FTE)

Budget for the year 2003: 5.0% of the total CSNII budget

4. Publications in refereed journals (in 2002): 5

5. Conference talks (in 2002): 9

6. Number of undergraduate and doctoral thesis on the experiment:

15 (INFN only)

7. Leadership roles and primary responsibilities in the experiment:

Coordination of the Silicon Tracker, Coordination of the Electromagnetic Calorimeter, Coordination of the Time of Flight system, Coordination of the Ring Imaging Cherenkov Detector, Co-chairmanship of the AMS Astrophysics Board, Chairman of AMS-Gamma Working group

8. Innovative instruments

Space qualitification of a several large, state of the art, particle detectors, including: Superconducting magnet, based on a very thin superconducting cable developed by a INFN-ETHZ Collaboration (LASA-Milano). Very large double sided Silicon Tracker (6 m2), 1 cubic meter, 10 um resolution in the bending plane. Solid state RICH detector based on high density multichannel photomultipliers. High accuracy Time of Flight (120 ps). Low power space qualified electronics. Qualified onboard software

9. Competing experiments

Pamela on the Russian Arktica in 2003-4 however with ~200 times smaller detector acceptance and 4 times lower maximum detectable rigidity.

10. International Committee which has reviewed the experiment

The AMS Experiment has been examined and approved by several international Committees among which:

- DoE referee Committee in April 1995 for the Shuttle Mission and in 1998 for AMS on the ISS
- INFN referee Committee in 1995, Russian Academy of Sciences in 1995.
- During 1995-96 various referees Committees have approved the participation to the AMS experiment in various countries/institutes: ETHZ, Swiss National Found, IN2P3, DARA, CIEMAT, TEKES.
- INFN annually reviews the experiment