Anton S. Tremsin

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The measurements of the electron cloud footprints produced by a stack of microchannel plates ͑MCPs͒ as a function of gain, MCP-to-readout distance and accelerating electric field are presented. To investigate the charge footprint variation, we introduce a ballistic model of the charge cloud propagation based on the energy and angular distribution at the MCP(More)
We have made substantial progress in the development of GaN photocathodes, including crystalline and polycrystalline GaN and InGaN coatings grown by chemical vapor deposition or molecular beam epitaxy on sapphire substrates. GaN and InGaN photocathodes have been developed with efficiencies up to 70% and cutoffs at $380 nm with low out of band response, and(More)
It was shown previously that CsI sensitivity can be substantially reduced by intense UV irradiation. In the present study we measure the influence of negative and positive electric fields on the degradation of CsI photocathode sensitivity when it is subject to a large dose UV irradiation. The UV sensitivity of positively biased CsI photocathodes did not(More)
—A detailed study of the stability of CsI and KBr pho-tocathodes under UV irradiation is presented. UV quantum efficiency degradation was found to be more pronounced at lower illumination intensity for the same accumulated dose and illumination wavelength. For an equal number of extracted photoelectrons in-band UV exposure led to a larger sensitivity decay(More)
The spatial resolution of current MCP based detector devices (<10 µm) has reached the point when such phenomenon as charge cloud asymmetry becomes important for the ultimate detector performance. We present a systematic study of the MCP charge cloud spatial distribution at the plane of the readout element. Our new readout – crossed strip (XS) anode combined(More)
The spatial resolution of high-accuracy microchannel plate ͑MCP͒ detectors has reached the values, where the so-called detector walk ͑or image blurring͒ may start to limit any further improvements. Image blurring with gain is studied in detail for detectors incorporating angular-biased MCPs. It was found that the presence of the pore bias at the output MCP(More)
Energy-resolved neutron imaging enables non-destructive analyses of bulk structure and elemental composition, which can be resolved with high spatial resolution at bright pulsed spallation neutron sources due to recent developments and improvements of neutron counting detectors. This technique, suitable for many applications, is demonstrated here with a(More)
Non-destructive testing techniques based on neutron imaging and diffraction can provide information on the internal structure of relatively thick metal samples (up to several cm), which are opaque to other conventional non-destructive methods. Spatially resolved neutron transmission spectroscopy is an extension of traditional neutron radiography, where(More)
A nondestructive study of the internal structure and compositional gradient of dissimilar metal-alloy welds through energy-resolved neutron imaging is described in this paper. The ability of neutrons to penetrate thick metal objects (up to several cm) provides a unique possibility to examine samples which are opaque to other conventional techniques. The(More)
This paper reports the design, making and characterisation of a series of Fe-based bulk metallic glass alloys with the aim of achieving the combined properties of high neutron absorption capability and sufficient glass forming ability. Synchrotron X-ray diffraction and pair distribution function methods were used to characterise the crystalline or amorphous(More)