Abstract: According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.

Abstract: The intrinsic background of a gamma ray spectrometer is significantly reduced by surrounding the scintillator with a second scintillator. This second (external) scintillator surrounds the first scintillator and has an opening of approximately the same diameter as the smaller central scintillator in the forward direction. The second scintillator is selected to have a higher atomic number, and thus has a larger probability for a Compton scattering interaction than within the inner region. Scattering events that are essentially simultaneous in coincidence to the first and second scintillators, from an electronics perspective, are precluded electronically from the data stream. Thus, only gamma-rays that are wholly contained in the smaller central scintillator are used for analytic purposes.

Abstract: According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.

Abstract: The intrinsic background of a gamma ray spectrometer is significantly reduced by surrounding the scintillator with a second scintillator. This second (external) scintillator surrounds the first scintillator and has an opening of approximately the same diameter as the smaller central scintillator in the forward direction. The second scintillator is selected to have a higher atomic number, and thus has a larger probability for a Compton scattering interaction than within the inner region. Scattering events that are essentially simultaneous in coincidence to the first and second scintillators, from an electronics perspective, are precluded electronically from the data stream. Thus, only gamma-rays that are wholly contained in the smaller central scintillator are used for analytic purposes.

Abstract: A multi-channel spectroscopy system that reads the radiation energy information deposited into a radiation detector, processes it and properly transfers it to a computer embedded to ancillary data (conditions, GPD information etc.). The implementation method chosen is a highly parallel structure of identical channels interfaced to the digital world through a custom-designed intelligent card (back-end) and a commercial data acquisition PC card.

Abstract: A method of making a highly sensitive epitaxial germanium low temperature sensor that is superior in the method of production and performance than those currently available. The geometry and sensitivity of the sensor can be tuned to desired temperature ranges, and specifically can operate at cryogenic temperatures. The sensor can be manufactured uniformly and reproducibly in large quantities at relatively low cost in which large area arrays are possible. The applications of the sensors range from conventional low temperature thermometry and control in laboratory and industrial settings, to applications associated with infrared, x-ray, particle and plasma physics and spectroscopy.

Abstract: A portable radiation detector using a high-purity germanium crystal as the sensing device. The crystal is fabricated such that it exhibits a length to width ratio greater than 1:1 and is oriented within the detector to receive radiation along the width of said crystal. The crystal is located within a container pressurized with ultra-pure nitrogen, and the container is located within a cryostat under vacuum.

Abstract: A method of making a highly sensitive epitaxial germanium low temperature sensor that is superior in the method of production and performance than those currently available. The geometry and sensitivity of the sensor can be tuned to desired temperature ranges, and specifically can operate at cryogenic temperatures. The sensor can be manufactured uniformly and reproducibly in large quantities at relatively low cost in which large area arrays are possible. The applications of the sensors range from conventional low temperature thermometry and control in laboratory and industrial settings, to applications associated with infrared, x-ray, particle and plasma physics and spectroscopy.

Abstract: A portable radiation detector using a high-purity germanium crystal as the sensing device. The crystal is fabricated such that it exhibits a length to width ratio greater than 1:1 and is oriented within the detector to receive radiation along the width of said crystal.

Abstract: A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

Abstract: Multi-element microcalorimeter array. The microcalorimeter array includes at least two microcalorimeter with each microcalorimeter including a detector coupled thermally to a cold bath. Each detector has associated with it a thermal sensor to generate a signal proportional to a rise in the detector's temperature. A single negative voltage feedback JFET preamplifier circuit is connected to each of the detectors and includes a JFET with a gate, the signals from the thermal sensors connected to the gate. The output of the preamplifier circuit is proportional to radiation energy absorbed by the detector. Each detector has a different thermal recovery time so that the detectors can be discriminated. The multiplexing arrangement of the invention makes it possible to reduce the overall number of preamplifier and post-processing channels for a large multi-element array. This reduction in turn significantly lowers the JFET heat load, mass and power requirements for the microcalorimeter array.

Abstract: A cryostat is provided which comprises a vacuum vessel; a target disposed within the vacuum vessel; a heat sink disposed within the vacuum vesssel for absorbing heat from the detector; a cooling mechanism for cooling the heat sink; a cryoabsorption mechanism for cryoabsorbing residual gas within the vacuum vessel; and a heater for maintaining the target above a temperature at which the residual gas is cryoabsorbed in the course of cryoabsorption of the residual gas by the cryoabsorption mechanism.