The Alpha-Gamma Program at NIST

The Alpha-Gamma device utilizes ${}^{10}$B(n,$\alpha$) capture on a totally absorbing deposit to measure the absolute neutron flux of a monochromatic cold neutron beam. This device has been successfully operated and used to improve the determination of the neutron flux for a neutron lifetime experiment. It is also being used for a measurement of the ${}^6$Li(n,t)${}^4$He cross section. We shall present its principle of operation along with the current and planned projects involving the Alpha-Gamma device, including the recalibration of the U.S. national neutron standard NBS-1, a ${}^{235}$U cross section measurement, and the calibration of flux monitors for a new measurement of the neutron lifetime