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)
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)
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)
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)