5
PAGE
Table of Contents
General Operation
7601 MURPHY DRIVE
MIDDLETON, WI 53562-2532 USA
WWW.STANDARDIMAGING.COM
4 General Precautions
5 General Operation
7 Parts and Accessories
8 Features and Specications
11 Service Notes
12 Service Policy
13 Customer Responsibility
14 Warranty
Exradin chambers are attached to a 1.5 m length of low-
noise exible triaxial cable that is terminated by a triaxial or
coaxial connector. The collector of the chamber is common
with the center wire of the cable and the center contact of the
connector. The guard is common with the inner cable braid
and the middle connector contact of triaxial connectors, and
the connector body of coaxial connectors. The shell (outer
electrode), usually ground, is common with the outer braid
of the cable and the connector body in the case of triaxial
connectors and the pigtail extending out the rear of coaxial
connectors.
The design of Exradin chambers requires that the collector
and guard operate at essentially the same potential. The
polarizing potential, supplied by an electrometer, is applied
between the shell and the guard. Either polarity may be
applied to the shell and either the shell or guard may be
grounded. Safety and other considerations recommend
grounding the shell, which then requires an electrometer
with a oating input.
All Exradin chambers can support 1000 V between shell and
guard. However, depending on the particular circumstance
and radiation intensity, as little as 90 V may yield essentially
100% charge collection.
Because Exradin ionization chambers do not exhibit volt-
age soakage phenomena, readings of ionization current
may be made immediately after application of the polar-
izing potential. However, it is good practice to pause a
minute or two after changing the potential to allow switch-
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