Beamstop with integrated X-ray sensor

A versatile beamstop with an integrated sensor has been developed at the Stanford Synchrotron Radiation Laboratory (SSRL) using non-specialized components. A diameter of 1.5 mm was achieved using a commercial subminiature surface mount PIN diode (Phillips BAP64) molded into a tungsten epoxy composite cup. The cup is supported on a thin fiberglass arm with printed circuit traces to transmit the signal from the diode. The assembly has an active area of approximately 100 µm in diameter. As the diode is encapsulated in plastic, the response diminishes with decreasing energy but is still useful at 6 keV.