Eberline ESP-1 - Page 24

The calibration constant will have to be changed when switching detectors. When changing
back
from
another
detector
to
the
detector
which
was
purchased
with
the
ESP-1,
use
the
calibration
constant
which
is
given
on
the
calibration
sheet
supplied
with
the
combined
ESP-1 and detector. Change values by pressing simultaneously either RESET and + or
RESET and -.
Selection of Calibration Constant for various detectors:
(1) If the detector was not purchased with the ESP-1 and, thus, a calibration sheet is not
available, use the nominal value for the particular Eberline detector which is given in
section V, "Maintenance," 11292-A36.
(2) To increase the value of CC, press RESET and + simultaneously. To decrease the
value of CC, press RESET and - simultaneously.
(3) To calculate a calibration constant for detectors other than those listed in the table, the
sensitivity of the detector must be known and is usually found in the list of
specifications given on the catalog sheet. Calculations using a HP-270 detector as an
example are given as follows:
sensitivity = 1200 c/min/mR/h
Calibration =
1200 c/min x 1000 mR/R x 60 min/h = 7.20 + 07 c/R
mR/h
4. Setting the Dead Time (DT)
a.
Definition:
The dead-time correction constant is a derived number used to correct for counting losses
due to inability of the detector to recover at high counting rates. This correction results in
a more linear response to the radiation field being measured and extends the useful range
of some detectors used with the ESP-1 by a factor of as much as ten times (which provides
the equivalent of an extra range on a standard rate meter).
Selection of "DT" for detectors which were purchased from the factory with the instrument:
If the ESP-1 was purchased with a detector from the factory, the DT value will be correctly
set at the factory and the next section may be bypassed until it is necessary to use a
different detector or until time for routine calibration.
When changing back from another detector to the detector purchased with the ESP-1, use
the DT given on the calibration shect supplied with the combined ESP-1 and detector.
ESPI.MAN/February 1992