Building a VME spectrometer and testing Si PIN diode detector: a feasibility study for the first nuclear astrophysical experiments using a pelletron

This work presents the logical design, connections between NIM and VME elec­tronic modules, and the data acquisition programming to build a complete detector readout system. The test experiments were carried out with commercial silicon PIN diode S3590-09 bare detectors bombarded by charged particles from a 241Am α-source and Rutherford elastic backscattering (RBS) protons induced by 2.5 MeV proton beam bombarding on an Au-on-glass target, and with a NaI scintillation detector bombarded by gammas from 27Al(p, γ)28Si reaction with proton beam energy of 1.379 MeV. The test showed that the spectrometer operated steadily and its versatility for different kind of detector. The energy resolutions of the Si diodes were less than 0.5% energy of a charged particle, which satisfies the foreseen requirement for the upcoming experiments.

A small and robust active beamstop for scattering experiments on high-brilliance undulator beamlines

A small active in-vacuum beamstop has been developed to monitor the flux of intense third-generation synchrotron X-ray beams protecting the downstream detector from the direct beam. Standard active beamstops, where a built-in diode directly absorbs the beam, have limitations in size and lifetime. In the present design, a silicon PIN diode detects the photons back-scattered from a cavity in the beamstop. This approach drastically reduces the radiation dose on the diode and thus increases its lifetime. The beamstop with a diameter of 2 mm has been fabricated to meet the requirements for the P12 bioSAXS beamline of EMBL Hamburg at PETRA III (DESY). The beamstop is in regular user operation at the beamline and displays a good response over the range of energies tested (6–20 keV). Further miniaturization of the diode is easily possible as its size is not limited by the PIN diode used.