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 BAP64-02) 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.

Installation at the beamline

Selected Reports

• Beamstop with integrated X-raysensor", P.Ellis, A.Cohen, and S. M. Soltis, "J. Synchrotron Rad. 10, 287-288 (2003).
  

Assembly

• Assembly instructions are described in the above publication.
• Additional photos depicting the process of molding the tungsten cup:
  Overall view of the mold
  Close-up of the mold and plunger
  Close-up of the beamstop inside the mold
  Beamstop removed from mold - before trimming excess epoxy
  Installation of beamstop at SSRL BL11-1
• We have found that only certain brands of epoxy should be used because some types use fillers that are not good insulators.  We suggest using 30 minute slow cure epoxy distributed by Bob Smith Industries.  This may be purchased from San Antonio Hobby Shop, Inc. 2550 El Camino Real, Mountain View, CA 94040 (650)941-1278.

Back to main hardware page