The Ludlum Model 9DP is a modern, digital, hand-held pressurized ion chamber
designed to detect gamma and X-ray energies above 25 keV. It will also see beta
energies above 1 MeV. The instrument can be configured to read in either in
units of Sv, R, or Gy and is readily changed by an administrator without requiring
a new calibration. The instrument is auto-ranging with a rate measurement range
of 0-50 mSv/h (0-5 R/hr, 0-50 mGy/h).