Hybrid linear array detectors for synchrotron radiation applications

A digital electronic glaziometer instrument for measuring the thicknesses of a glass panel and its constituent sheets and gaps is proposed. There is currently no reliable method or instrument for determining the thickness of individual glass plates or the distance between plates of an installed glass panel. A new device is proposed which uses a linear array detector to detect the positions of light beams reflected from the top and bottom surfaces of glass sheets. A breadboard model was built and experimental testing on a multi-glazed panel shows favorable results. Factors affecting instrument accuracy are discussed

Towards real-time VMAT verification using a prototype, high-speed CMOS active pixel sensor.

This work investigates the feasibility of using a prototype complementary metal oxide semiconductor active pixel sensor (CMOS APS) for real-time verification of volumetric modulated arc therapy (VMAT) treatment. The prototype CMOS APS used region of interest read out on the chip to allow fast imaging of up to 403.6 frames per second (f/s). The sensor was made larger (5.4 cm × 5.4 cm) using recent advances in photolithographic technique but retains fast imaging speed with the sensor's regional read out. There is a paradigm shift in radiotherapy treatment verification with the advent of advanced treatment techniques such as VMAT. This work has demonstrated that the APS can track multi leaf collimator (MLC) leaves moving at 18 mm s(-1) with an automatic edge tracking algorithm at accuracy better than 1.0 mm even at the fastest imaging speed. Evaluation of the measured fluence distribution for an example VMAT delivery sampled at 50.4 f/s was shown to agree well with the planned fluence distribution, with an average gamma pass rate of 96% at 3%/3 mm. The MLC leaves motion and linac pulse rate variation delivered throughout the VMAT treatment can also be measured. The results demonstrate the potential of CMOS APS technology as a real-time radiotherapy dosimeter for delivery of complex treatments such as VMAT

Using a large area CMOS APS for direct chemiluminescence detection in Western Blotting Electrophoresis

Western blotting electrophoretic sequencing is an analytical technique widely used in Functional Proteomics to detect, recognize and quantify specific labelled proteins in biological samples. A commonly used label for western blotting is Enhanced ChemiLuminescence (ECL) reagents based on fluorescent light emission of Luminol at 425nm. Film emulsion is the conventional detection medium, but is characterized by non-linear response and limited dynamic range. Several western blotting digital imaging systems have being developed, mainly based on the use of cooled Charge Coupled Devices (CCDs) and single avalanche diodes that address these issues. Even so these systems present key drawbacks, such as a low frame rate and require operation at low temperature. Direct optical detection using Complementary Metal Oxide Semiconductor (CMOS) Active Pixel Sensors (APS)could represent a suitable digital alternative for this application. In this paper the authors demonstrate the viability of direct chemiluminescent light detection in western blotting electrophoresis using a CMOS APS at room temperature. Furthermore, in recent years, improvements in fabrication techniques have made available reliable processes for very large imagers, which can be now scaled up to wafer size, allowing direct contact imaging of full size western blotting samples. We propose using a novel wafer scale APS (12.8 cm×13.2 cm), with an array architecture using two different pixel geometries that can deliver an inherently low noise and high dynamic range image at the same time representing a dramatic improvement with respect to the current western blotting imaging systems

Charge-coupled imagers for time-resolved macromolecular crystallography

There exists considerable promise for the use of charge‐coupled device (CCD) imagers in the fast recording of parts of macromolecular crystal Laue diffraction patterns. As part of this development CCD tests have been made with direct detection of Laue patterns from a small molecule test crystal and a protein crystal. Merging R factors (on intensity), for strong reflections, of 3% have been obtained. A time‐slicing scheme for a CCD camera is discussed based on the stacking of slices held in storage in the CCD in the submillisecond time resolution range

Imaging of moving fiducial markers during radiotherapy using a fast, efficient active pixel sensor based EPID.

The purpose of this work was to investigate the use of an experimental complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) for tracking of moving fiducial markers during radiotherapy

CMOS APS in pre-clinical science: next generation disruptive technology for multi-modality imaging

A new large area CMOS Active Pixel Sensor has been developed as single platform technology to be used across a range of ionizing and non-ionizing imaging applications in preclinical science, ranging from imaging of protein sequences to functional analysis of radio-labeled tissue sections.We present the first images of chemiluminescence detection in western blotting with a room temperature CMOS APS. Detection performance in western blotting have been compared with the gold standard detection medium, film emulsion, showing higher dynamic range and sensitivity with this new device. We also report on our first images of 125IEpibatidine autoradiography of brain sections using a novel large area CMOS APS. © 2012 IEEE

CCDs for x-ray topography at Synchrotrons.

An X-ray sensitive CCD camera has been evaluated at the Daresbury Synchrotron Radiation Source (SRS) for use in X-ray topographic (XRT) studies of epitaxially grown, strain-layered semiconductors (InGaAs/GaAs). Current topographic images obtained with photographic emulsion plates require considerable exposure and processing times of up to an hour so that real-time XRT cannot be realised. However, results from the X-ray sensitive CCD camera have shown that misfit dislocation features in the sample wafer topograph can be revealed in exposure times of less than 15 min. Results obtained from the CCD are presented. Finally, a number of further improvements to the camera system are possible using recent developments in CCD technology which will improve the resolution and sensitivity and allow higher resolution topographs to be obtained in around 30 s, close to the goal for real-time imaging of layer growth by molecular beam epitaxy (MBE). These further developments and the implications on the performance of a new camera system for X-ray topography are discussed

DynAMITe: A wafer scale sensor for biomedical applications

In many biomedical imaging applications Flat Panel Imagers (FPIs) are currently the most common option. However, FPIs possess several key drawbacks such as large pixels, high noise, low frame rates, and excessive image artefacts. Recently Active Pixel Sensors (APS) have gained popularity overcoming such issues and are now scalable up to wafer size by appropriate reticule stitching. Detectors for biomedical imaging applications require high spatial resolution, low noise and high dynamic range. These figures of merit are related to pixel size and as the pixel size is fixed at the time of the design, spatial resolution, noise and dynamic range cannot be further optimized. The authors report on a new rad-hard monolithic APS, named DynAMITe (Dynamic range Adjustable for Medical Imaging Technology), developed by the UK MI-3 Plus consortium. This large area detector (12.8 cm × 12.8 cm) is based on the use of two different diode geometries within the same pixel array with different size pixels (50 μm and 100 μm). Hence the resulting device can possess two inherently different resolutions each with different noise and saturation performance. The small and the large pixel cameras can be reset at different voltages, resulting in different depletion widths. The larger depletion width for the small pixels allows the initial generated photo-charge to be promptly collected, which ensures an intrinsically lower noise and higher spatial resolution. After these pixels reach near saturation, the larger pixels start collecting so offering a higher dynamic range whereas the higher noise floor is not important as at higher signal levels performance is governed by the Poisson noise of the incident radiation beam. The overall architecture and detailed characterization of DynAMITe will be presented in this paper