New methods to identify low energy 3He with Silicon-based detectors

International audienceMethods to discriminate low energy mass-3 particles using Silicon detectors are reviewed. The time-of-flight technique based on analog electronics and measuring time between a reference signal and the charge signal from the Silicon detector does not allow to discriminate 3He from H. One method consists in adding a thin layer of Silicon (typically of ) to recover the standard discrimination by E-E identification matrix. Strong inhomogeneities in thickness are observed for these thin detectors. Difficulties in handling such detectors have led to investigate numerical approaches using reverse-mounted neutron transmutation doped Silicon detectors. First, the pulse shape analysis (PSA) technique has been investigated on the current and charge signals. PSA enables the discrimination of tritons and 3He and also 3He and 4He with good figures of merit. Secondly, the time of flight between two digitized signals (a reference signal from the beam pulse and the current or the charge signal) is presented. Both numerical techniques give promising results for the identification of light particles with Silicon detectors

Pulse shape discrimination at low energies with a double sided, small-pitch strip silicon detector

We achieved particle separation of proton, deuteron and triton at energies ranging between 2 and 10 MeV by the processing of digitized signals obtained with a double-sided, 485-μm pitch strip, 500-μm thick neutron transmutation doped (nTD) silicon detector. We produced the light charged particles in a nuclear reaction induced by a 34-MeV beam of 7Li impinging on a 12C target. We analyzed offline the signals with the goal of a simplified, possibly analog, front-end electronics in mind for the processing of the 15,000 channels of the new state-of-the-art detectors for low energy nuclear physics like GASPARD, HYDE and TRACE which should make use of such methods. At the optimum bias, using the current amplitude versus charge correlation, we obtain a separation of 3 FWHM between protons and deuteron, and 2 FWHM between deuteron and triton at energies as low as 2 MeV; with a square bipolar filter, suited for simple implementation, we separate them by 4.3 and 2.7 FWHM respectively at 5 MeV

Single-particle strength in neutron-rich 71Cu from the (d,3He) proton pick-up reaction

We have measured the 72Zn(d,3He)71Cu proton pick-up reaction in inverse kinematics at 38 MeV/u. A dedicated set-up was developed to overcome the experimental challenges posed by the low cross section of the reaction and the low energy of the outgoing 3He particles. The excitation-energy spectrum was reconstructed and spectroscopic factors were obtained after analysis of the angular distributions in the finite-range Distorted-Wave Born Approximation (DWBA). The results show that unlike for the \u3c0f5/2 orbital, the \u3c0f7/2 singleparticle strength is not appreciably affected by the addition of neutrons beyond N 40. \ua9 Published under licence by IOP Publishing Ltd