Publication details
Characterization of the graphite pile as a source of thermal neutrons
| Authors | |
|---|---|
| Year of publication | 2015 |
| Type | Article in Periodical |
| Magazine / Source | Radiation Physics and Chemistry |
| MU Faculty or unit | |
| Citation | |
| Web | http://www.sciencedirect.com/science/article/pii/S0969806X15000353 |
| Doi | http://dx.doi.org/10.1016/j.radphyschem.2015.01.028 |
| Field | Nuclear, atomic, and moleculary physics |
| Keywords | Thermal neutrons; Graphite pile; Cadmium ratio; 3He proportional detectors |
| Description | A new graphite pile designed to serve as a standard source of thermal neutrons has been built at the Czech Metrology Institute. Actual dimensions of the pile are 1.95 m (W)×1.95 m (L)×2.0 m (H). At its center, there is a measurement channel whose dimensions are 0.4 m×0.4 m×1.25 m (depth). The channel is equipped with a calibration bench, which allows reproducible placement of the tested/calibrated device. At a distance of 80 cm from the channel axis, six holes are symmetrically located allowing the placement of radionuclide neutron sources of Pu–Be and/or Am–Be type. Spatial distribution of thermal neutron fluence in the cavity was calculated in detail with the MCNP neutron transport code. Experimentally, it was measured with two active detectors: a small 3He proportional detector by the French company LMT, type 0.5 NH 1/1 KF, and a silicon pixel detector Timepix with 10B converter foil. The relative values of thermal neutron fluence rate obtained with active detectors were converted to absolute ones using thermal neutron fluence rates measured by means of gold foil activation. The quality of thermal neutron field was characterized by the cadmium ratio. |