A stopping layer concept to improve the spatial resolution of GEM neutron detector

2021 ◽  
Author(s):  
Jianjin Zhou ◽  
Jianrong Zhou ◽  
Xiaojuan Zhou ◽  
Lin Zhu ◽  
Jianqing Yang ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Neutron Beam ◽  
Neutron Detector ◽  
High Spatial Resolution ◽  
Neutron Detection ◽  
Drift Region ◽  
Electron Multiplier ◽  
Good Spatial Resolution ◽  
Counting Range ◽  
High Dynamic

Abstract In recent years, Gas Electron Multiplier (GEM) neutron detector has been developing towards high spatial resolution and high dynamic counting range. A novel concept of the Al stopping layer was proposed to enable the detector to achieve sub-millimeter (sub-mm) spatial resolution. The neutron conversion layer was coated with the Al stopping layer to limit the emission angle of ions into the drift region. The short track projection of ions was obtained on the signal readout board, and the detector would get good spatial resolution. The spatial resolutions of the GEM neutron detector with Al stopping layer were simulated and optimized based on Geant4GarfieldInterface. When Al stopping layer was 3.0 μm thick, drift region was 2 mm thick, strip pitch was 600 μm, and digital readout was employed. The spatial resolution of the detector was 0.76 mm, and the thermal neutron detection efficiency was about 0.01%. Thus, the GEM neutron detector with a simple detector structure and a fast readout mode was developed to obtain a high spatial resolution and high dynamic counting range. It could be used for the direct measurement of a high-flux neutron beam, such as Bragg transmission imaging, very small-angle scattering neutron detection and neutron beam diagnostic.

Novel instrument system for discriminating secondary particles in high-spatial-resolution neutron detection

2004 ◽  
Vol 75 (7) ◽  
pp. 2340-2345 ◽  
Author(s):  
H. Yamagishi ◽  
T. Nakamura ◽  
K. Soyama ◽  
S. Masaoka ◽  
K. Aizawa
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Neutron Detection ◽  
Secondary Particles

scholarly journals Molecular imaging of atherosclerosis: spotlight on Raman spectroscopy and surface-enhanced Raman scattering

Heart ◽  
2017 ◽  
Vol 104 (6) ◽  
pp. 460-467 ◽  
Author(s):  
Neil MacRitchie ◽  
Gianluca Grassia ◽  
Jonathan Noonan ◽  
Paul Garside ◽  
Duncan Graham ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Molecular Imaging ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Photon Emission ◽  
Surface Enhanced Raman Spectroscopy ◽  
Emission Tomography ◽  
Good Spatial Resolution ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

To accurately predict atherosclerotic plaque progression, a detailed phenotype of the lesion at the molecular level is required. Here, we assess the respective merits and limitations of molecular imaging tools. Clinical imaging includes contrast-enhanced ultrasound, an inexpensive and non-toxic technique but with poor sensitivity. CT benefits from high spatial resolution but poor sensitivity coupled with an increasing radiation burden that limits multiplexing. Despite high sensitivity, positron emission tomography and single-photon emission tomography have disadvantages when applied to multiplex molecular imaging due to poor spatial resolution, signal cross talk and increasing radiation dose. In contrast, MRI is non-toxic, displays good spatial resolution but poor sensitivity. Preclinical techniques include near-infrared fluorescence (NIRF), which provides good spatial resolution and sensitivity; however, multiplexing with NIRF is limited, due to photobleaching and spectral overlap. Fourier transform infrared spectroscopy and Raman spectroscopy are label-free techniques that detect molecules based on the vibrations of chemical bonds. Both techniques offer fast acquisition times with Raman showing superior spatial resolution. Raman signals are inherently weak; however, leading to the development of surface-enhanced Raman spectroscopy (SERS) that offers greatly increased sensitivity due to using metallic nanoparticles that can be functionalised with biomolecules targeted against plaque ligands while offering high multiplexing potential. This asset combined with high spatial resolution makes SERS an exciting prospect as a diagnostic tool. The ongoing refinements of SERS technologies such as deep tissue imaging and portable systems making SERS a realistic prospect for translation to the clinic.

scholarly journals Development of high spatial resolution cold/ultra- cold neutron detector using fine-grained nuclear emulsion

2017 ◽  
Author(s):  
Naotaka Naganawa ◽  
Shogo Awano ◽  
Masahiro Hino ◽  
Masanori Hirose ◽  
Katsuya Hirota ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Neutron Detector ◽  
Nuclear Emulsion ◽  
High Spatial Resolution ◽  
Cold Neutron ◽  
Fine Grained ◽  
Ultra Cold Neutron

A two-dimensional gas detector with individual readouts for neutron detection with a high spatial resolution and fast temporal response

2005 ◽  
Vol 76 (9) ◽  
pp. 093302 ◽  
Author(s):  
Hiroki Tanaka ◽  
Tatsuya Nakamura ◽  
Hideshi Yamagishi ◽  
Kazuhiko Soyama ◽  
Kazuya Aizawa
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Neutron Detection ◽  
Two Dimensional ◽  
Temporal Response ◽  
Gas Detector

RAINBOWS: refractive analysis of the incoming neutron beam over the white spectrum. A new fast neutron reflectometry technique exploiting a focusing prism

2018 ◽  
Vol 51 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Robert Cubitt ◽  
Jaime Segura Ruiz ◽  
Werner Jark
Keyword(s):  
Fast Neutron ◽  
Spatial Resolution ◽  
Neutron Beam ◽  
Traditional Method ◽  
High Spatial Resolution ◽  
Neutron Reflectometry ◽  
Small Samples ◽  
Neutron Reflectivity ◽  
Wavelength Resolution ◽  
Opening Up

Neutron reflectivity is a powerful technique for characterizing interfaces in many areas of science. The traditional method of time of flight for measuring the wavelength of neutrons in a white beam is extremely wasteful, as the vast majority of neutrons must be absorbed in the choppers in order to produce a pulsed beam. A prism operates continuously, with a transmission up to two orders of magnitude higher than choppers. The wavelength-dependent deflection of the beam by the prism, coupled with a high spatial resolution detector, results in excellent wavelength resolution. The theory of how the resolution is considerably enhanced by curving the surface of the prism is described in detail for a real experimental arrangement. It is demonstrated how this can be used for faster neutron reflectometry, including the merging of different angles and subtraction of background. The technique shows considerable promise for neutron reflectivity, opening up new areas of science particularly in the realms of kinetics and small samples.

High spatial resolution AEM observations of yttrium segregation in chromia scales grown on Co-45%Cr

1986 ◽  
Vol 44 ◽  
pp. 518-519
Author(s):  
K. Przybylski ◽  
A. J. Garratt-Reed ◽  
G. J. Yurek
Keyword(s):  
Spatial Resolution ◽  
Outer Surface ◽  
Maximum Concentration ◽  
High Spatial Resolution ◽  
Reactive Elements ◽  
Chromia Scales

The addition of so-called “reactive” elements such as yttrium to alloys is known to enhance the protective nature of Cr2O3 or Al2O3 scales. However, the mechanism by which this enhancement is achieved remains unclear. An A.E.M. study has been performed of scales grown at 1000°C for 25 hr. in pure O2 on Co-45%Cr implanted at 70 keV with 2x1016 atoms/cm2 of yttrium. In the unoxidized alloys it was calculated that the maximum concentration of Y was 13.9 wt% at a depth of about 17 nm. SIMS results showed that in the scale the yttrium remained near the outer surface.

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