Low Energy X-ray Imaging Research Articles

Fast, high density avalanche photodiode array

Using bevelled edge avalanche photodiode technology, we have built a high density 64-element array, with center-to-center spacing of 450 /spl mu/m. The array was built by etching grooves in the back side of a large area avalanche photodiode. The pattern for etching and metalization of the pixels on the back side was done with photolithography. This technique allows for good control of the groove depth. The cross talk between pixels is related to the resistance between them and is dependent on the bias applied to the detector. Because of the small pixel size, the rise time with an impulse excitation approaches /spl sim/0.9 ns. These arrays have very good potential for light or low energy X-ray imaging systems and optical fiber readout in detectors for high energy physics detectors. >

Detection of foreign particles in traumatized skin

The aims of the medico-legal investigation of wounds are a description of the wound morphology, the characterization of the force used and finally identification of the weapon. The demonstration of foreign particles, such as wood particles, paint fragments, synthetic materials, sand or gravel particles, powder residues and rust particles, in the depth of a wound or in the surrounding area can be of great value. In the present series of experiments the suitability of imaging methods (low energy X-ray imaging, direct X-ray magnification, nuclear magnetic resonance) for the detection of relevant foreign particles has been investigated.

Fe VIII, IX, and X Line Emission From the Soft X-ray Background: Previous Limits and a Future Measurement

AbstractWe discuss pulse height analysis of Be band data in relation to the important 72 eV Fe line cluster emission from the soft X-ray background (SXRB). Pulse height fits to the Be band data suggest that the Fe lines must be suppressed by a factor of ~10 with respect to the rest of the X-ray spectrum. The broad band rates and the mean energy of the pulse height data for the Be band can be brought into agreement by using depleted elemental abundance emission models. A planned measurement of the SXRB Fe lines using the Array of Low Energy X-ray Imaging Sensors (ALEXIS) experiment could resolve this issue.

Characterization Of Fluorescent Screens For Imaging Applications With Mev Neutrons And Photons

Inorganic phosphor screens that are normally designed for low-energy x-ray imaging applications are shown to be useful for imaging with photons and neutrons having MeV energies. Characterizations of a number of commercially available phosphors with regard to detection efficiency for radiation type and energy, effective spatial resolution, optical self-absorption, response time, and spectral emissions are tabulated. Applications to high-energy x-ray imaging, nuclear fuel rod imaging, and nuclear fusion source imaging are shown to be feasible.

Low-energy x-ray imaging of laser plasmas

A major fraction of the x-ray flux from laser-produced plasmas is in the subkilovolt regime. The spectral content in this region is measured with x-ray diodes, which contain no spatial information. We present a description of a pinhole camera that operates in the 200-300-eV range. This permits the correlation of an image with corresponding x-ray diode data. The construction and operation of the camera are described, and low-energy and high-energy photographs of a laser-irradiated gold sphere are presented.