LUSCAT (Lunar Soil Composition Analysis Telescope): An Instrument To Detect X And Gamma Ray From The Moon

Transcription

1 (Lunar Soil Composition Analysis Telescope): An Instrument To Detect X And Gamma Ray From The Moon P. Battaglia 1, A. Bonati 1, P.H. Leutenegger 1, M. Pecora 1,F.Perotti 2, G. Villa 2, C. Labanti 3 Template reference : K-EN 9 th ILEWG, October 22 nd -26 th 2007, Sorrento, Italy 1 Thales Alenia Space Italia S.p.A., S.S. Padana Superiore 290, Vimodrone (MI) 2 INAF-IASF Milano, Via Bassini 15, Milano 3 INAF-IASF Bologna, Via Gobetti 101, Bologna

2 Introduction (1/2) Page 2 Why going on the Moon to observe the Universe? Our satellite is a superb and unique platform to observe the Cosmos at a variety of wavelengths and viewing conditions, especially in the high-energy region of the electromagnetic spectrum. The Moon is an ideal place to build an astronomical observatory because it offers a stable platform, with full sky visibility if located on the equator, without the need of a pointing system if the telescopes can operate in drift mode, and with continuous observation capability. Earth s atmosphere opacity

3 Introduction (2/2) Page 3 Geological studies of the Moon are based on a combination of Earth based telescope observations, measurements from orbiting spacecraft, lunar samples, and geophysical data. A handful of lunar meteorites have been recognized on Earth, though their source craters on the Moon are unknown. A substantial portion of the lunar surface has not been explored and a number of geological questions are still unanswered. Full Moon (near side) at a telescope Lunar rock samples Apollo 17

4 Page 4 (LUnar Soil Composition Analysis Telescope) is the results of an engineering effort to join a detector to characterise the Moon radiation environment and a detector to study the lunar emission (fluorescent lines and gamma rays). 1. Analysis of the lunar soil composition by detecting the Moon emission fluorescent lines kev Gamma Rays 10 MeV orbiter instrument in orbiter configuration 2. Characterisation of the lunar albedo (regolith energy emission under incoming radiation excitation) operating on the lunar soil in coordination with the one on the orbiter

5 Architecture (1/2) Page 5 1. Silicon Drift Chamber with Cesium Iodide (CsI), 10 x 10 units, and a CsI anticoincidence system. This configuration foresees the utilisation of Silicon Drift Chambers, to detect the X radiation emitted by fluorescence, and CsI for higher energies. The anti-coincidence system is composed of CsI, 3 cm thick. 2. Silicon Drift Chambers coupled with CsI (10 x 10 units) and a Bismuth Germanium Oxide (BGO) anti-coincidence system. Also for this configuration it is foreseen the utilization of Silicon Drift Chambers to detect the X radiation emitted by fluorescence and CsI for higher energies. The anti-coincidence system is composed of BGO, 2 cm thick. (SDC+CsI;CsI anticoincidence) (SDC+CsI; BGO anticoincidence)

6 Architecture (2/2) Page 6 3. A third possible telescope schematic is based on a scintillation detector composed of an LaBr3 crystal 7 x 7 cm2, 5 cm thick coupled to a CsI crystal 1 cm thick both seen by the same PMT (Phoswich Detector). The Phoswich detector has a BGO anti-coincidence system, with optical fibers and photomultipliers. All the configurations proposed have a field of view of 150 km x 150 Km at 100 km altitude (important for the orbiter). The field of view angle is of about 74 x74. (LaBr3+CsI; BGO anticoincidence) (CAD rendering)

7 Conclusions Page 7 The Moon presents a complex radiative and geological environment which is still not completely know. (LUnar Soil Composition Analysis Telescope) is a detector that enable the characterisation of the Moon radiative environment as well as the study of the lunar emission (fluorescent lines and gamma rays). The characterisation of the lunar radiative environment is important also for future lunar missions, especially those that foreseen instruments installation on the soil. design is suitable both for orbiter and ground observations data correlation. The detector modularity is important for redundancy and improved data collection (great number of samples).