A piece of interstellar medium in the laboratory: the PIRENEA experiment

The new astrochemistry experiment PIRENEA is presented. The set-up was designed to approach the physical conditions that prevail in the interstellar medium. It enables to perform original studies in particular when large molecules and nano-sized particles are involved. The experiment is now operational for science

Photophysics of interstellar PAHS

This paper reports the first results obtained on the photodissociation of the isolated PAH cations 12C24H+12, 13C12C23H+12 and 12C24H+10, using the astrochemistry experimental set-up PIRENEA. The dissociation patterns of these ions involve the loss of pairs of hydrogen atoms. A first interpretation indicates that the -H2 dissociation path is favoured compared to the -H path in our experimental conditions. These results might have important implications on the formation of H2 in the interstellar medium

Degradation and recovery of Ge detectors: tests prior to a space mission

Ge detectors onboard the future INTEGRAL mission of ESA will be deteriorated by secondary neutrons. In the present work, flight model Ge detectors were degraded by accelerator-produced neutrons, and then annealed. The detector recovery was found very sensitive to the annealing temperature. Transients following a high-voltage cut-off were studied as well. (C) 2002 Elsevier Science B.V. All rights reserved

Influence of temperature on the behaviour of INTEGRAL n-type HPGe detectors irradiated with fast neutrons

Several INTEGRAL n-type HPGe detectors have been irradiated by fast neutrons at different temperatures and their performances have been evaluated. Their behaviour during warm-up and cool-down cycles following the irradiations show evidence for irreversible temperature effects above 100 K. The detectors recovery after annealing was also studied. (C) 1999 Elsevier Science B.V. All rights reserved

Fast neutron-induced damage in INTEGRAL n-type HPGe detectors

Several INTEGRAL n-type HPGe detectors have been irradiated by fast neutrons and their degradation studied through the analysis of line shapes. The availability of three different fast neutron beams (5, 16 and 6-70 MeV) allowed a quantitative analysis of the importance of the neutron energy on the amount of damage. A comparison is made with the degradation induced by high-energy proton irradiations. Transient effects on the measured resolution are reported after high voltage cut-off on degraded detectors. (C) 1999 Elsevier Science B.V. All rights reserved

Neutron-induced nuclear reactions and degradation in germanium detectors

We have measured cross sections of neutron-induced nuclear reactions leading to the delayed production of -ray lines similar to the ones of astrophysical interest. Conclusions were drawn concerning the expected background in the 26Al 1809 keV line and the 7Be 478 keV line in SPI. The neutron-induced degradation of Ge detectors was studied vs. the neutron energy, the neutron fluence and the detector temperature. Performance recovery of the detectors was studied for different annealing temperatures. Optimum temperature and times for annealing were determined