Numerical Simulations of Pillar Structured Solid State Thermal Neutron Detector: Efficiency and Gamma Discrimination

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper reports numerical simulations of a three-dimensionally integrated, Boron-10 (<formula formulatype="inline"><tex Notation="TeX">$^{10}$</tex> </formula>B) and Silicon p+, intrinsic, n<formula formulatype="inline"><tex Notation="TeX">${+}$</tex></formula> (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and <formula formulatype="inline"><tex Notation="TeX">$^{7}$</tex></formula>Li) created from the neutron-<formula formulatype="inline"><tex Notation="TeX">$^{10}$</tex> </formula>B reaction. In this paper, the effect of both the 3-D geometry (including pillar width, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the experimental data available at this time, for 7- and 12-<formula formulatype="inline"><tex Notation="TeX">$\mu$</tex></formula>m tall micropillar arrays. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible. </para>