Ricochet
Search for the Coherent Elastic Nuclear Scattering of Neutrinos from a reactor
Reactor hall, H7 position, 8.8 m from the reactor core
| ILL site | ||
|---|---|---|
| Start position | 8m from the reactor core | neutrino flux (1.2 1012 ν/cm2/s) |
| Available space | 3 m wide x 6 m long x 3.5 m high | below 15 m water equivalent (m.w.e.) against cosmic radiations |
| Backgrounds | well characterized | well-shielded against irradiation from the reactor and neighboring instruments (IN20 and D19) |
| Cryostat and shielding | ||
|---|---|---|
| Hexa-Dry 200 Ultra-quiet cryostat CryoConcept company), France | Dry cryogen-free Ultra-quiet technology | cold stages at 50K, 4K, 1K, 100 mK and 10 mK |
| 10 mK stage | holds the detector | |
| 1 K stage | holds cold shielding & cold-front end electronics |
| Vibrations | ||
|---|---|---|
| must be suppressed > 50 Hz | insulation of inner frame from the floor | passive with visco-elastic materials |
| Height | 40 mm |
| Backgrounds | ||
|---|---|---|
| cosmogenic and radiogenic | CRY (cosmic rays) and MCNP models | Geant4 simulations |
| Expected 350 Hz muon-veto trigger rate | dead-time between 20-30% |
| Detector | ||
|---|---|---|
| CryoCube | array of 27 (3×3×3) high purity germanium crystal detectors | encapsulated in a radio-pure infrared-tight copper box |
| Particle identification threshold | 100eV |
INSTRUMENT DESCRIPTION
Ricochet is deployed at the ILL-H7 site in the reactor hall.
The H7 site starts at about 8 m from the ILL reactor core that provides a nominal nuclear power of 58.3 MW, leading to a neutrino flux at the Ricochet detectors 8.8 m from the reactor core of about 1.2×1012 cm−2s−1. The reactor is operated in cycles of typically 50 days’ duration with reactor-off periods sufficiently long to measure reactor-independent backgrounds, such as internal radioactivity or cosmogenic induced backgrounds, with high statistics. The available space is about 3 m wide, 6 m long and 3.5 m high. It is located below a water channel providing about 15 m water equivalent (m.w.e.) against cosmic radiations. It is not fed by a neutron beam and is well-shielded against irradiation from the reactor and neighboring instruments (IN20 and D19).