Neutron spectroscopy from 1 to 15 MeV with Mimac-FastN, a mobile and directional fast neutron spectrometer and an active phantom for BNCT and PFBT

Abstract

In the frame of direct dark matter search, the fast neutrons producing elastic collisions on the nuclei of the active volume are the ultimate background. The MIMAC (MIcro-tpc MAtrix Chambers) project has developed a directional detector providing the directional signature to discriminate them from the searched events based on 3D nuclear tracks reconstruction. The MIMAC team of the LPSC has adapted one MIMAC chamber as a mobile fast neutron spectrometer, the Mimac-FastN detector, having a wide neutron energy range (10 keV – 600 MeV) working with different gas mixtures and pressures. This presentation will be focused on the MeV range with 4He + 5% CO2 gas mixture at 700 mbar. A boron coating inside the active volume used for calibration purpose opens the possibility to use the active volume as an active phantom for Boron Neutron Capture Therapy (BNCT) and Proton Fusion Boron Therapy (PFBT).

NCT-WES: A new single moderator directional neutron spectrometer for neutron capture therapy. Experimental validation

“…In addition, it is today common experts' opinion that the neutron spectrum at the beam port should be measured [2]. Existing neutron spectrometers have been proposed [4] for this task, but at present they do not cover the whole energy range of interest, typically spanning from thermal up to MeV energies. This work describes a new directional spectrometer, especially conceived for use in neutron captures therapy, called NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer) and developed within the INFN project ENTER BNCT.…”

Methodology for an experimental drift velocity determination using a μTPC. Example in a 700mbar 95%He+5%CO2 mixture

“…In the following, we calculate the recoil nucleus energy using the IQF law computed using the TRIM option of the SRIM software [11]. The ionization energy is deduced from the charge collection profile using a calibration of the µTPC carried out using the alpha from the 10 B(nth, 7 Li) 4 He reaction [12].…”