R&D on Boron Multi-Grids detectors done at the Institut Laue Langevin

The BrightnESS project is a partnership between researchers of the Institut Laue Langevin (ILL, Grenoble) and ones of the European Spallation Source (ESS,Lund). The Lund site will be the place where the next european neutron beam will be built. That is why; in the context of the future experiences that will be conducted, ESS scientists show their interests in R&D of large-scale neutron detectors. Many of these detectors will use a technology alternative to 3He ones, considered as expensive and low-malleable mechanically. In the optic of the time of flight experience RAMSES, the ILL proposed to develop boron multi-grids technology in order to respond to the ESS needs.

The goal of my job was to prove that this technology is advantageous for experiences where thermal neutron detection is desired. To do this, two prototypes MG12 and IN6 were built, modified and tested.

The main research performed are :

1) plateau measurement, energy spectra, detection efficiency.

2) neutron/gamma discrimination.

3) scattered neutrons.

4) maximale rate withstood.

5) rate homogeneity, uniformity and stability.

6) operating mode at several pressures (from 100 mbars to 1 Bar).

7) spatial resolution.

8) readout electronic and acquisition system.

9) possible improvements in electronic and in mechanic.