Showing papers by "Nathal Severijns published in 2000"

The behaviour of HPGe detectors operating at temperatures below 77 K

Abstract: Planar detectors from high-purity germanium single crystals designed for the detection of charged particles in low-temperature nuclear orientation experiments were tested in the temperature range 4.5–77 K. Various detector characteristics were measured. The distortions in spectra observed at the lowest temperatures are discussed. Good performance of the detectors in real experimental conditions was obtained.

Computer simulations for the design of calorimetric detectors

Abstract: It is often impossible to determine the optimum detector geometry, thermistor doping and operating conditions prior to fabrication. We therefore suggest a software approach. A computer code, which allows to simulate the heat transport and electrical coupling, has been developed and is applied to actual calorimeters. The overall agreement between calculated detector features and corresponding experimental findings is found to be good.

Nuclear orientation of radioactive 56 Mn ions implanted in the insulators MnCl 2 ⋅ 4 H 2 O and CoCl 2 ⋅ 6 H 2 O

Abstract: Low-temperature nuclear orientation experiments on radioactive ${}^{56}\mathrm{Mn}$ ions implanted into insulating, antiferromagnetic crystals of ${\mathrm{MnCl}}_{2}\ensuremath{\cdot}4{\mathrm{H}}_{2}\mathrm{O}$ and ${\mathrm{CoCl}}_{2}\ensuremath{\cdot}6{\mathrm{H}}_{2}\mathrm{O}$ are reported. In ${\mathrm{MnCl}}_{2}\ensuremath{\cdot}4{\mathrm{H}}_{2}\mathrm{O},$ comparison of the $\ensuremath{\gamma}$-ray anisotropy of the ${}^{56}\mathrm{Mn}$ nuclei with that of ${}^{54}\mathrm{Mn},$ doped into the sample during growth, showed that both the ${}^{56}\mathrm{Mn}$ and ${}^{54}\mathrm{Mn}$ spins felt a very similar hyperfine field. The site occupancy factor in a simple, two-site model was deduced to be ${0.96}_{\ensuremath{-}0.07}^{+0.04}.$ In ${\mathrm{CoCl}}_{2}\ensuremath{\cdot}6{\mathrm{H}}_{2}\mathrm{O},$ the average hyperfine field for the implanted ${}^{56}\mathrm{Mn}$ was significantly less than that for ${}^{54}\mathrm{Mn}$ and corresponded to $f=0.53\ifmmode\pm\else\textpm\fi{}0.10.$