Efficiency optimization of microchannel plate (MCP) neutron imaging detectors. I. Square channels with 10B doping

Abstract

Microchannel plate (MCP) event-counting imaging detectors with very high spatial resolution (~10 µm) and timing accuracy (~100 ps) are widely employed for the detection and imaging applications of electrons and ions, as well as UV and X-ray photons.Recently it was demonstrated that the many advantages of MCPs are also applicable to neutron detection with high 2-dimensional spatial resolution. Boron, enriched in the isotope 10 B, was added to the MCP glass structure to enhance the neutron interaction within the MCP through the 10 B(n,α) 7 Li reaction. The energetic charged particle reaction products release secondary electrons directly into MCP channels, initiating an electron avalanche and a subsequent strong output pulse. In this paper we present a detailed model for calculating the quantum detection efficiency of MCP neutron detectors incorporating * Corresponding author. E-mail address: ast@ssl.berkeley.edu (A.S.Tremsin) 2 10 B, for the specific case of square channel MCP geometry. This model predicts that for thermal neutrons (0.025 eV), MCP detection efficiencies of up to 78% are possible using square channels. We also show theoretically that square channel MCPs should have a very sharp (~ 17 mrad) angular drop in sensitivity for detection of normal incidence neutrons, opening up new possibilities for angle-sensitive neutron imaging as well as collimation. The calculations can be used to optimize MCP neutron detection efficiency for a variety of applications. In a subsequent companion paper, the model will be extended to the case of hexagonally-packed circular channels.

Development of a novel neutron detection technique by using a boron layer coating a Charge Coupled Device

“…Preliminary experimental tests indicate that this technique could be also employed by using boron coating a CMOS device. CCD and CMOS devices with timing resolutions of about 1 s are used in neutron imaging applications [21][22][23][24] and are commercially available. The mentioned devices will also allow to use this technique in neutron time-of-flight measurements.…”

Mapping of axial plastic zone for roller bearing overloads using neutron transmission imaging

“…For this experiment, a time resolution of 4.48 μswasset.TheMCPhasa detection efficiency of approximately 50% for neutron energy ranges relevant for to this study [49]. Details of the detector and its specifications can be found elsewhere [48,50].…”

Neutron Imaging with Timepix Coupled Lithium Indium Diselenide

“…Again, the cost, size and complexity of such an imaging system greatly impacts the application space. The Microchannel Plate (MCP) technology was adapted to neutron detection by integrating 10 B in the glass channel sidewall [8]. Coupled to a high resolution ASIC (application specific integrated circuit), the MCP has shown high speed detection windows at a resolution of roughly 10 µm, limited by the channel pore distance [9,10].…”