X-ray detection system for wavelength dispersive and energy dispersive spectroscopy and electron beam applications

Apparatus for detecting X-rays incident thereon, comprising:

• an avalanche photodiode detector having a slab of semiconductor material with a first face on which incident X-rays impinge and a second face on the opposite side of the slab from the first face, a conductive entrance window electrode with a thickness less than ten nanometers covering the first face and a conductive collection electrode covering the second face;
• a voltage source that applies a reverse bias voltage across the entrance window electrode and the collection electrode;
• a mechanism that tilts the detector so that the entrance window electrode is at an angle relative to the incident X-rays in order to increase a detection efficiency for X-rays scattered from “heavy” elements;
• and
• a signal processing circuit connected to the avalanche photodiode detector including an ultra-low noise amplifier, a dual channel discriminator, a scaler and a digital counter.

A wavelength-dispersive spectrometer for measuring X-rays generated when an electron beam strikes a sample, the spectrometer comprising:

• an X-ray detector;
• a crystal;
• and
• a spectrometer mechanism that positions the crystal relative to the generated X-rays so that X-rays with a selected wavelength are incident on the X-ray detector, wherein the X-ray detector is an avalanche photodiode detector having a slab of semiconductor material with a first face on which incident X-rays impinge and a second face on the opposite side of the slab from the first face, a conductive entrance window electrode with a thickness less than ten nanometers covering the first face and a conductive collection electrode covering the second face.