Showing papers by "Anton S. Tremsin published in 2007"

High spatial resolution neutron sensing microchannel plate detectors

Abstract: Neutron sensing microchannel plates (MCPs) developed by Nova Scientific Inc incorporate high-efficiency neutron conversion materials in the MCP glass to provide a high neutron stopping power We have developed and tested neutron event counting 2D-imaging detectors using these MCPs with three different imaging systems, a cross delay line readout, a cross strip readout, and a MEDIPIX readout Tests at MNRC and NIST with the cross delay line and cross strip readouts have established spatial resolution with neutrons as good as 17 μm RMS over 27 mm, with event rates of 1 MHz, event time tagging of 25 ns and intrinsic background rates of −2 s −1 MEDIPIX readouts for neutron imaging have poorer spatial resolution (55 μm) and event timing, but are capable of even higher rates (GHz)

Microchannel plates: recent advances in performance

Abstract: Microchannel plates have, because of their adaptability to various size and configuration formats, allowed a wide range of devices to be realized in astronomical applications for X-ray, UV and visible sensing, employing many different forms of readout techniques and photocathode types. Two essential performance issues are the quantum detection efficiency, and the uniformity of response over the detector field of view. In both of these areas microchannel plates have had issues, both in the consistency of high quantum detection efficiency, and in fixed pattern noise introduced by fabrication processes for microchannel plates. We show that recent work has improved the consistency of obtaining high quantum detection efficiency, and has virtually eliminated the causes of fixed pattern noise due to fabrication issues.

High-resolution detection system for time-of-flight electron spectrometry

Abstract: One of the key components of a time-of-flight (TOF) spectrometer is the detection system. In addition to high timing resolution, accurate two-dimensional imaging substantially broadens the areas of applications of TOF spectrometers; for example, add a new dimension to angle-resolved photoemission spectroscopy (ARPES). In this paper we report on the recent developments of a high spatial ( The electron detection system reported in the paper was developed for the TOF ARPES experiments at the Advanced Light Source, Lawrence Berkeley National Laboratory.

Complete momentum and energy resolved TOF electron spectrometer for time-resolved photoemission spectroscopy

Abstract: Over the last decade, high-resolution Angle-Resolved Photoemission Spectroscopy (ARPES) has emerged as a tool of choice for studying the electronic structure of solids, in particular, strongly correlated complex materials such as cuprate superconductors. In this paper we present the design of a novel time-of-flight based electron analyzer with capability of 2D in momentum space (kx and ky) and all energies (calculated from time of flight) in the third dimension. This analyzer will utilize an improved version of a 2D delay linedetector capable of imaging with<35 mm (700x700 pixels) spatial resolution and better than 120 ps FWHM timing resolution. Electron optics concepts and optimization procedure are considered for achieving an energy resolution less than 1 meV and an angular resolution better than 0.11.

High performance cross-strip detector technologies for space astrophysics

Abstract: We describe a novel MCP imaging detector scheme using the Cross Strip (XS) anode This anode uses charge division, and centroiding, of microchannel plate charge signals detected on two orthogonal layers of sense strips to encode event X-Y position, event time and signal amplitude We have developed novel XS anode structures that will, in combination with a new generation of small pore MCP's (< 4 mum pores), perform at the highest resolution levels (<10 mum) with self triggered ~1 ns timing accuracy and encode photons at greater than 1 MHz rates Our development the XS charge division scheme has been demonstrated with formats up to 32 mm2 They show excellent resolution (better than 7 mum FWHM, actually imaging the MCP pores) using low MCP gain (5 times 105) We have investigated XS anode structures that will accommodate a wide variety of forms (circular, square, rectangular) We are using this concept to produce open face and sealed tube detectors for imaging a wide range of photon and particle events To encode event positions we have designed and built a parallel channel encoding electronics The front end boards utilize two RD-20, 32 channel preamplifier ASICs The pre- amplified signal is post-amplified on the same board in order to match the dynamic range of downstream 60 Msps ADCs that constantly digitize the signal for subsequent digital peak detection Tests with eight 60 Msps ADC channels and a software Finite Impulse Response algorithm demonstrate < 5 mum electronic resolution and <10 mum resolution with a 32 mm XS anode detector A full 64 channel 60 Msps ADC circuit has been constructed along with a Xilinx Virtex 5 FPGA event processing board In combination with firmware based Xilinx centroiding algorithms, encoding the event positions at more than 1 MHz rates over large areas should also be possible Such detector system may be used for a variety of future missions, in solar, solar system and astronomical applications

High resolution neutron imaging at high counting rates with noiseless readout

Abstract: We describe the design and report on the experimental results of a novel thermal and cold neutron imaging detector utilizing neutron sensitive (10B-doped) microchannel plates (MCPs) In this detector, the incoming neutron interaction products produce secondary electrons at the pores adjacent to the absorption point within the MCP glass This electron signal is then multiplied by a stack of conventional MCPs within those adjacent pores limiting the spread of the signal to less than two pore diameters (currently 6-10 mum pores on 8-12 mum centers) The event position then can be encoded by a number of readout techniques already developed for photon/charged particle counting applications This paper presents the results of experimental evaluation of neutron sensing MCP detector with Medipix2 readout allowing operation at high counting rate mode (>100 MHz level) at a spatial resolution limited by the 55 mum pixel size of the Medipix2 readout Other attractive features of MCP neutron detectors are their high detection efficiency (approaching 50% levels) for thermal and cold neutrons and the absence of readout noise