A multi-element silicon detector for X-ray flux measurements

A 30 element Si(Li) detector was fabricated to measure the one dimensional flux profile of 33 KeV X-rays from a synchrotron radiation beam. The device, which is fabricated from a single 39 mm x 15 mm silicon wafer, is a linear array of 0.9 mm x 7 mm elements with a 1 mm center to center spacing. It is 5 mm thick and when operated at room temperature has an average leakage current of 10 nA/element. The X-ray flux in each element is determined by measuring the current with a high quality operational amplifier followed by a current digitizer. This detector is being used to study the use of synchrotron radiation for non-invasive imaging of coronary arteries. The experiment uses the differences in the transmitted flux of a monochromatized X-ray beam above and below the iodine K-edge. Measurements were made on plastic phantoms and on excised animal hearts with iodinated arteries.