Speaker
Gianpiero Gervino
(Università di Torino / INFN)
Description
The proliferation of neutron detection application based upon $^3$He proportional counter has triggered a critical shortage of $^3$He gas. The annual demand of $^3$He for US homeland security alone has been evaluated more than the worldwide supply, with the effect of limiting the perspectives of nuclear physics applications that up to now rely strongly upon $^3$He-based detectors. Nowadays there is an increasing demand for alternative neutron detection technologies that can cover large solid angle, have low sensitivity to gamma background and, last but not least, low cost. We present a low cost neutron detector based upon a long cylindrical metal tube coated on the inside with a thin layer of $^{10}$B-enriched boron carbide ($^{10}$B$_4$C). $^{10}$B-rich layer captures neutrons: $^{10}$B undergoes to (n,$\alpha$) reaction producing an $\alpha$-particle and a $^7$Li recoil nucleus that travel off in opposite direction. The movement of both creates ion pairs when crossing the gas inside the cylinder. The best gas for neutron detection efficiency that could be used is boron trifluoride (BF$_3$) also enriched in $^{10}$B, but this gas is expensive and also on the black list of gases associated to the atmospheric ozone depletion. Nitrogen gas is used as low cost alternative. We present the preliminary performances of the detector 180 cm long and 6 cm diameter with a nitrogen pressure ranging from 1 to 3.5 atm, exposed to $^{252}$Cf source. Neutron relative detection efficiency compared to $^3$He set-up is evaluated and discussed.
Primary author
Gianpiero Gervino
(Università di Torino / INFN)
Co-authors
Prof.
Andrea Lavagno
(Dipartimento di Fisica and INFN, Politecnico di Torino, Italy)
Dr
Antonio Scarfone
(ISC-CNR and INFN Torino, Italy)
Dr
Carlo Palmisano
(Dipartimento di Fisica and INFN Torino, Italy)
Dr
Dorina Devona
(SELEX Galileo, San Giorgio Canavese (TO), Italy)
Dr
Massimo Balma
(SELEX Galileo, San Giorgio Canavese (TO), Italy)
