Large volume multiple path nuclear lasing of3He-Ar

Output power of 550 W has been achieved from a nuclear-pumped multiple path laser system containing
³
He-Ar by using the
³
He(n, p)
³
H nuclear reaction for power deposition. Lasing was achieved in Ar at 1790 nm. The complex beam profile was resolved by an InAs array detector. Lasing threshold thermal neutron fluxes as low as
2 \times 10^{15}
n/cm
²
. s have been demonstrated for 79.8 kPa (600 torr)
³
He- (2 percent)Ar mixtures with peak fluxes of
3 \times 10^{16}
n/cm
²
. s. Laser output was directly proportional to thermal neutron flux, and also increased proportionally with increasing
³
He pressure up to 292.6 kPa (2200 torr). The variation of the laser output power with the number of passes through the excited medium was found to peak at 5-7 passes.