Improved efficiency of high resolution thermal and cold neutron imaging

✍ Scribed by A.S. Tremsin; J.B. McPhate; J.V. Vallerga; O.H.W. Siegmund; W.B. Feller; E. Lehmann; M. Dawson

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 520 KB
• Volume: 628
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2010.07.014

✦ Synopsis

Spatial resolution and detection efficiency of neutron imaging detectors are the crucial parameters defining the ultimate resolution in neutron radiography, micro-tomography and other non-destructive testing techniques. The most widely used neutron imaging systems use a neutron-sensitive scintillation screen lens coupled to a CCD or a CMOS sensor. The highest spatial resolution in those devices is achieved using very thin scintillation screens which reduce image blurring due to light spreading in the scintillator. Thus high spatial resolution and high detection efficiency usually could not be achieved in the same device. Neutron counting detectors using neutron-sensitive microchannel plates (MCPs) overcome that deficiency by providing a long neutron absorption path ($ mm scale) and preserving events within a single sub-10 mm pore. At the same time, each neutron in those detectors can be timetagged with $ 1 ms accuracy. The latest 10 B and gadolinium-doped MCPs developed by Nova Scientific were tested at the cold neutron facility ICON of Paul Scherrer Institute and proved to be capable of imaging cold neutrons with 70% detection efficiency. Neutron radiography and micro-tomography confirmed the high spatial resolution capabilities of the latest generation of high efficiency microchannel plates.

The high spatial and temporal resolution of our neutron counting detectors allows for high resolution micro-tomography, novel studies of material composition, texture, phase and strain through Bragg edge imaging as well as dynamic studies of magnetic fields inside of thick samples, exploiting the neutron spin interactions with magnetic fields.