PAMELA is a satellite-borne experiment that aims to measure the antiproton and positron spectra in the cosmic radiation over the largest energy range ever achieved, and to search for antinuclei with unprecedented sensitivity. In addition, it will measure the light nuclear component of cosmic rays and investigate phenomena connected with Solar and Earth physics. All detectors have been successfully integrated in the apparatus that has been installed on-board the Russian ResursDK1 satellite. In the first months of 2006 PAMELA will be launched from the Baikonur cosmodrome in Kazakhstan, for a 3 year long mission. In this paper an overview of the mission and the instrument will be presented, along with results of cosmic ray muons recorded at ground during the final integration phase

Roberta Sparvoli

Undetermined

Open Access Repository

November 7, 2005 17:10 Proceedings Trim Size: 9in x 6in icatpp˙sparvoliLAUNCH IN ORBIT OF THE SPACE TELESCOPE PAMELAAND GROUND DATA RESULTSR. SPARVOLI FOR THE PAMELA COLLABORATIONUniversity of Rome ”Tor Vergata” and INFN structure of ”Tor Vergata”PAMELA is a satellite-borne experiment that aims to measure the antiproton andpositron spectra in the cosmic radiation over the largest energy range ever achieved,and to search for antinuclei with unprecedented sensitivity. In addition, it willmeasure the light nuclear component of cosmic rays and investigate phenomenaconnected with Solar and Earth physics. All detectors have been successfullyintegrated in the apparatus that has been installed on-board the Russian Resurs-DK1 satellite. In the first months of 2006 PAMELA will be launched from theBaikonur cosmodrome in Kazakhstan, for a 3 year long mission. In this paper anoverview of the mission and the instrument will be presented, along with resultsof cosmic ray muons recorded at ground during the final integration phase.1. Experiment overviewThe PAMELAa apparatus is designed to study charged particles in thecosmic radiation. It will be hosted by a Russian Earth-observation satellite,the Resurs-DK1, that will be launched into space by a Soyuz rocket in 2006from the Baikonur cosmodrome. The orbit will be elliptical and semi-polar,with an inclination of 70.4◦ and an altitude varying between 350 km and600 km. The mission will last at least three years.The main scientific goal of the experiment is the precise measurement ofthe cosmic-ray antiproton and positron energy spectra. The satellite orbitand mechanical design of the apparatus will allow the identification of theseparticles in an unprecedented energy range (between 80 and 270 MeV forpositrons and between 80 and 190 MeV for antiprotons) and with highstatistics (∼ 104 p and ∼ 105 e+ per year). The importance of thesemeasurements stems from the information that they can provide aboutsolar modulation effects (below a few GeV), cosmic-ray propagation andprimary production from exotic sources such as primordial black holes,annihilation of supersymmetric particles or Kaluza-Klein particles. Almostaa Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics.1November 7, 2005 17:10 Proceedings Trim Size: 9in x 6in icatpp˙sparvoli2Figure 1. A sketch of the PAMELA apparatus.all data available so far have been obtained by balloon-borne experiments.New and extensive measurements with high statistics are strongly needed.Additionally, PAMELA will search for antimatter in the cosmic radia-tion (sensitivity to the He/He of ∼ 10−8), it will measure the light nuclearcomponent of cosmic rays and investigate phenomena connected with Solarand Earth physics.2. The apparatus PAMELAThe apparatus 1 is composed of the following sub-detectors, arranged as inFigure 1, from top to bottom: a time of flight system (ToF (S1,S2,S3)), ananticoincidence system (CARD, CAT, CAS), a magnetic spectrometer, anelectromagnetic imaging calorimeter, a shower tail catcher scintillator (S4)and a neutron detector.Particles trigger the experiment via the main triggerb provided bythe ToF system 2 composed of 6 layers of segmented plastic scintillatorsbAdditional triggers can be provided by the calorimeter and S4.November 7, 2005 17:10 Proceedings Trim Size: 9in x 6in icatpp˙sparvoli3arranged in three planes (S1, S2, S3). The ToF system also measures theabsolute value of the particles charge and flight time crossing its planes.In this way downgoing particles can be separated from upgoing ones. Fur-thermore, the acceptance of the apparatus can be varied by changing theconfiguration of the ToF layers used to form the trigger. Particles notcleanly entering the PAMELA acceptance are rejected by the anticountersystem 3. The rigidities of the particles are determined by the magneticspectrometer 4 consisting of a permanent magnet and a silicon trackingsystem. Thus, positively and negatively charged particles can be identi-fied. The final identification (i.e. positrons, electrons, antiprotons, etc.) isprovide by the combination of the calorimeter (see 5) and neutron detectorinformation plus the velocity measurements from the ToF system at lowmomenta.The detector is approximately 120 cm high, has a mass of about 450 kgand the power consumption is 360 W.A daily amount of about 10 GByte of data from the instrument areexpected. The main downlink center is located at the Research Center forEarth operative monitoring ”Nts-OMZ” in Moscow (Russia); an average of8 passages per day over the station are foreseen, during which PAMELAwill download all scientific data along with telemetry data about the statusof the detector (temperatures, power consumptions, voltage levels, ..). Anadditional station, located in Khanty-Mansiisk (Siberia, Russia), is underconsideration, but has not been officially established yet.3. Ground data resultsPrior to the delivery to Samara (Russia), where the spacecraft is built, thePAMELA apparatus was assembled at the laboratories of the University ofRome ”Tor Vergata”, Italy. Here the system was tested with ground muonsover a period of several months, in order to calibrate the sub-detectors andcheck the overall performance of the instrument. As a whole, a total ofabout 480 hours of ground cosmic rays have been collected.Figure 2 shows an event recorded in Rome. The event is a 1.5GeV/negatively charged particle, with high probability of being a µ− con-sidering the clean non-interacting pattern in the calorimeter. All PAMELAdetectors are shown in the figure along with the signals produced by theparticle in the detectors and derived information. It can be clearly seenthe highly detailed information provided for each cosmic-ray event. Thesolid line indicates the track reconstructed by the fitting procedure of theNovember 7, 2005 17:10 Proceedings Trim Size: 9in x 6in icatpp˙sparvoli4-0.521.5-0.521.5PALETTETOF, CALO, S4 [MIP]:0 0 - 2 2 - 10 10 - 100 100 - 500 > 500ND [neutrons]:0  1 - 2  3 - 6  7 - 14  15 - 30 > 30AC: NOT HIT  HIT trigger  HIT backgroundCARD4CARD1CARD2CARD3CAS3CAS4CAS2CAS1CAT1CAT2CAT3CAT4CAS2 CAS1 CAS4 CAS3CARD2 CARD3 CARD1 CARD4CAT3 CAT4 CAT2 CAT1CalorimeterCalorimeterTrackerTrackerNDNDS3S2S1S3S2S1S4 S4CPU SIDECPU SIDEVME SIDEVME SIDECPU SIDEzxyX VIEW Y VIEWy xzxyzFigure 2. A muon track in PAMELA.tracking system. From this information the muon charge ratio measuredat ground in Rome (50 m a.s.l.) has been obtained and shown in Figure3. Muons were selected as non interacting particles in the calorimeter andcharge one in the ToF scintillators. Their momenta were determined bythe tracking system. In the figure PAMELA data are compared with otherexperimental results 6,7,8. A good agreement can be seen.Once PAMELA reached Samara, it was extensively tested again beforebeing integrated inside the spacecraft. As a result, about 140 hours ofcosmic ray acquisition have been recorded. Analysis of Samara data is inprogress.4. Status of the missionExtensive space qualification tests of PAMELA detectors, electronics andmechanical structures have been performed. Furthermore, the detectorswere tested at test beam facilities at CERN and shown to comply withtheir design specification.Three models of the PAMELA apparatus were developed: amass/thermal model, a technological model for electrical and compatibil-November 7, 2005 17:10 Proceedings Trim Size: 9in x 6in icatpp˙sparvoli5momentum (GeV/c)µ+ / µ-Hebbeker and Timmermans (world average  2002)BESS-95 (Tsukuba, Japan)BESS-97/98/99 (Lynn Lake, Canada)CAPRICE-98 (Fort Sumner, New Mexico)PAMELA preliminary (Rome, Italy)00.250.50.7511.251.51.7522.252.510-11 10 102Figure 3. µ+/µ− ratio as measured by PAMELA during ground data acquisition -preliminary results.ity tests with the satellite, and the flight model for actual data taking inspace 9. All these models were delivered for testing to Samara, and shownto be fully compliant with the requirements of the Resurs-DK1 spacecraftenvironment. Specifically, the flight model underwent incoming and ac-ceptance tests in April/May 2005 and was integrated with the satellite inSeptember 2005. Electrical and data transmission tests of the integratedPAMELA-spacecraft system are still taking place.Subsequently, PAMELA and the satellite will be transported toBaikonur for the launch into space, foreseen for the beginning of 2006 afterabout two months of tests in-situ.References1. M. Bongi et al., IEEE Trans. Nucl. Sci. 51, 854 (2004).2. D. Campana et al., 28th ICRC, Tsukuba, 2141 (2003).3. S. Orsi et al., 35th COSPAR, Paris, to appear in Adv. Sp. Res. (2004).4. O. Adriani et al., Nucl. Instr. & Meth. A 511, 72 (2003).5. M. Boezio et al., Nucl. Instr. & Meth. A 487, 407 (2002).6. T. Hebbeker and C. Timmermans, Astropart. Phys. 18, 107 (2002).7. M. Motoki et al., Astropart. Phys. 19, 113 (2003).8. M. Boezio et al., Phys. Rev. D 67, 072003 (2003).9. R. Sparvoli et al., 35th COSPAR, Paris, to appear in Adv. Sp. Res. (2004).

Launch in Orbit of the Space Telescope Pamela and Ground Data Results

https://www.openaccessrepository.it/record/141347/files/fulltext.pdf

Launch in Orbit of the Space Telescope Pamela and Ground Data Results

Abstract

Similar works

Full text

Available Versions

Open Access Repository