Understanding Neutron Radiography Post Exam Reading VIII-Part 2a of 2A

Personnel Monitoring Instruments
Pocket Chambers
Personnel monitoring instruments, some the size of a ball point pen, are
usually the integrating type and contain an ionization chamber. One version,
the pocket chamber, requires the application of an initial charge of 150 to 200
V by an external instrument. Zero dose is then indicated on a scale contained
in the charging unit. Exposure of the chamber to ionization decreases the
initial charge. When the chamber is reconnected to the charging unit the
reduced charge is translated to the level of exposure (Fig. 8).
Charlie Chong/ Fion Zhang