A compact x-ray beam intensity monitor using gas amplified sample current measurement

Development of a compact beam intensity monitor using gas amplified sample current measurement is described. The monitor can be a powerful tool for x- ray spectroscopy and microscopy when the beam is defined by a small pinhole or slits and when the workspace around the sample is limited. The thicknes s of the monitor is as small as approximately 3 mm, and the dimension is 10 mm square. The photon flux is monitored by measuring x-ray excited current from an Al foil under atmospheric conditions. Emitted electrons from the A l foil can ionize surrounding air molecules, and the gas amplified current can be measured with the use of a biased grid that prevents created ion pai rs from recombination. (C) 2000 American Institute of Physics. [S0034-6748( 00)02501-6].