GRIT

GRIT stands for “Granularity, Resolution, Identification, Transparency”. It is a new generation silicon array for low energy nuclear physics built conjointly at the european level: France (IJCLab, LPC Caen, GANIL), Italy (INFN-Padova, INFN-LNL, INFN-Milano, and INFN-Firenze), Spain (IFIC-Valencia , University of Santiago de Compostela, and University of Huelva), and the UK (University of Surrey).

GRIT offers the unique possibility to investigate nuclear structure and nuclear astrophysics with high efficiency and high resolution by coupling with state-of-the-art gamma array like AGATA, PARIS, EXOGAM2, MINIBALL…

Below is the foreseen timeline for MUGAST/GRIT.

GRIT aims at measuring direct reactions of nuclear strucutre and/or nuclear astrophysics interest.  Direct reactions are a powerful tool in nuclear physics. The relative simplicity of the reaction mechanism involving few degrees of freedom, allow precise theoretical calculations to be made and nuclear structure information to be extracted from experimental data.

Performed in inverse kinematics, where a radioactive beam impinges on a light target (H, He,…), they require the measurement and the identification of the recoiling light particle with high accuracy. Silicon based detectors are particularly well-suited as they combine high granularity with good energy resolution. Combined with  gamma arrays, they can benefit from their excellent energy resolution (few keV) and achieve excellent performances. This is why GRIT is designed to be coupled with state-of-the-art gamma arrays like AGATA, PARIS, EXOGAM2 or MINIBALL.

Several Letters of Intent have been written to perform experiments at HIE-ISOLDE, SPES, FAIR and Spiral2

The GRIT array is composed of :

• 2 rings of trapezoidal telescopess in the forward and backward direction
• 1 ring of square telescopes at 90 degrees
• 2 annular detectors in the most forward and backward angles

Each telescope consist of :

• one 500 um thick first layer of nTD (neutron transmutation doped) type Double Sided Stripped Silicon detectors (DSSSD) with 128 strips on each side
• one or two (in the forward hemisphere) 1.5 mm thick DSSSD with larger pitch (32 strips on each side).

The thin trapezoidal and square prototypes have been developed and fully tested on a test bench. The energy resolution is of about 50 keV all strips summed.

A thick (1.5mm) square detector has also been developed and tested with an alpha source. The obtained energy resolution is of about 70 keV (FWHM).