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Abstract: Transition edge sensors (TESs) are high-sensitivity thermometers used in cryogenic microcalorimeters which exploit the steep gradient in resistivity with temperature during the superconducting phase transition. Practical TES devices tend to exhibit a white noise of uncertain origin, arising inside the device. We discuss two candidate models for this excess noise, phase slip shot noise (PSSN) and percolation noise. We extend the existing PSSN model to include a magnetic field dependence and derive a basic analytical model for percolation noise. We compare the predicted functional forms of the noise current vs. resistivity curves of both models with experimental data and provide a set of equations for both models to facilitate future experimental efforts to clearly identify the source of excess noise. [ABSTRACT FROM AUTHOR]

Abstract: Modern microchannel plate detectors exhibit low quantum efficiency in the extreme ultra violet range compared to those manufactured before 1990. The cause of this reduction in efficiency is unknown. We describe recent investigations into the along-channel surface compositions of a number of microchannel plates (MCPs) of varying efficiency. These compositional profiles, generated using energy-dispersive X-ray spectroscopy, provide insight into possible mechanisms underlying the efficiency reduction and may assist in efforts to restore good extreme ultraviolet (EUV) performance to MCPs through modifications to the manufacturing process. [Copyright &y& Elsevier]

A fast imaging electron detector is being developed as part of the Toroidal Energy- and Angle-Resolved Electron Spectrometer (TEARES), a high-resolution electron spectrometer for use on synchrotron sources. The analysed solid angle of TEARES is about 100 times greater than that of a conventional hemispherical analyser of similar radius and entrance slit sizes. A ‘typical’ solid sample at a third-generation synchrotron source would yield count rates in excess of 1 GHz, >103 times the capability of available imaging electron detectors. We describe a prototype detector based on low-resistance microchannel plates and an adaptation of the cartesian two-dimensional CODACON encoder that aims to achieve a relatively modest 2 MHz counting rate with 32 by 128 simultaneous energy and angle channels. The encoder pattern has been optimised for the output electron distribution of TEARES and directly generates a binary address for each event using simple electronics and the minimum number of signal channels. [Copyright &y& Elsevier]

Fast neutron radiography is a non-destructive testing technique with a variety of industrial applications and the capability for element sensitive imaging for contraband and explosives detection.Commonly used position sensitive detectors for fast neutron radiography are based on charge coupled devices (CCDs) and scintillators. The limited format of CCDs implies that complex optical systems involving lenses and mirrors are required to indirectly image areas that are larger than 8.6 cm×11.05 cm. The use of optics reduces the light collection efficiency of the imaging system, while the efficiency of hydrogen rich scintillators exploiting the proton recoil reaction is limited by the hydrogen concentration and the magnitude of the neutron scattering cross-section.The light conversion step inevitably involves a tradeoff in scintillator thickness between light yield and spatial resolution.The development of large area amorphous silicon (a-Si) panel flat panel photodiode arrays and direct neutron-to-charge converters based on microchannel plates, provide an attractive new form of high resolution, large area, fast neutron imaging detector for the non-destructive imaging of large structures. This paper describes some recent results of both Monte Carlo simulations and measurements for such a detector. [Copyright &y& Elsevier]

Abstract: We report on a new optimal filtering algorithm for improved energy and position resolution in position sensitive Transition Edge Sensor (TES) based X-ray detectors. This algorithm takes account of the noise correlation between the detector outputs to minimise the variance on the estimated photon energy and position. Using numerical methods we show that improved energy and position resolution can be obtained than from previously published methods. Our simulations also reveal the trade-offs resulting from changes in the thermal conductances and heat capacities of the detector elements. [Copyright &y& Elsevier]

Abstract: We describe optimal filtering algorithms for determining energy and position resolution in position-sensitive Transition Edge Sensor (TES) Distributed Read-Out Imaging Devices (DROIDs). Improved algorithms, developed using a small-signal finite-element model, are based on least-squares minimisation of the total noise power in the correlated dual TES DROID. Through numerical simulations we show that significant improvements in energy and position resolution are theoretically possible over existing methods. [Copyright &y& Elsevier]

Abstract: We report on the experimental characterisation and modelling of Transition Edge Sensor (TES)-based Distributed Read-Out Imaging Devices (DROIDs), for use as position-sensitive detectors in X-ray astronomy. Latest experimental results from prototype DROIDs using Ir TESs with Au absorbers are reported. Through modelling and the development of signal processing algorithms we are able to design the DROID for optimum spectral and spatial resolution depending upon application. [Copyright &y& Elsevier]

We are investigating Transition-Edge Sensors (TESs) for future X-ray Astronomy missions. In this paper, we report the first X-ray results from a one-dimensional imaging spectrometer or Distributed Read-Out Imaging Device (DROID). The DROID consists of two Iridium TESs with transitions temperatures of ∼172 mK, at the ends of a 250 μm by 4.7 mm Gold absorber. The event position can be determined from pulse height and rise/fall time information. Initial results were obtained by reading one end of the DROID only. [Copyright &y& Elsevier]