Neutron radiography with sub-15 μm resolution through event centroiding

Abstract

Conversion of thermal and cold neutrons into a strong ∼1ns electron pulse with an absolute neutron detection efficiency as high as 50–70% makes detectors with 10B-doped Microchannel Plates (MCPs) very attractive for neutron radiography and microtomography applications. The subsequent signal amplification preserves the location of the event within the MCP pore (typically 6–10μm in diameter), providing the possibility to perform neutron counting with high spatial resolution. Different event centroiding techniques of the charge landing on a patterned anode enable accurate reconstruction of the neutron position, provided the charge footprints do not overlap within the time required for event processing. The new fast 2×2 Timepix readout with >1.2kHz frame rates provides the unique possibility to detect neutrons with sub-15μm resolution at several MHz/cm2 counting rates. The results of high resolution neutron radiography experiments presented in this paper, demonstrate the sub-15μm resolution capability of our detection system. The high degree of collimation and cold spectrum of ICON and BOA beamlines combined with the high spatial resolution and detection efficiency of MCP-Timepix detectors are crucial for high contrast neutron radiography and microtomography with high spatial resolution. The next generation of Timepix electronics with sparsified readout should enable counting rates in excess of 107n/cm2/s taking full advantage of high beam intensity of present brightest neutron imaging facilities.