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)
Neutron dark-field imaging constitutes a seminal progress in the field of neutron imaging as it combines real space resolution capability with information provided by one of the most significant neutron scattering techniques, namely small angle scattering. The success of structural characterizations bridging the gap between macroscopic and microscopic(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)
Results from a fully independent thin film process for manufacturing non-lead glass Microchannel plate (MCP) detectors using nano-engineered thin films for both the resistive and emissive layers are presented. These novel MCP devices show high gain, less gain degradation with extracted charge, and greater pore to pore and plate to plate uniformity than has(More)
The optical constants of thin films of CsI, KI, and KBr and the quantum efficiency (QE) of planar photocathodes made with these alkali halides in the 53.6-174.4-nm spectral range are presented. The optical constants were obtained from measurements of the reflectance as a function of incidence angle. The effect of film heating and exposure to UV irradiation(More)
A detailed study of possible image displacements in MCP detectors due to the presence of MCP pore bias is presented. We show that fluctuations of the rear accelerating field, characteristic to some MCP detector configurations, result in translational shifts of the entire image, which degrade the detector spatial resolution. It was experimentally observed(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)