Eberline ESP-1 - Page 53

5-4
4.
Rate Meter Calibration
For
clarity,
a
brief
overview
of
the
readout
determination
follows:
a. The
average
count
rate
is
calculated
each
one-half
second.
This
average
is
maintained
in
counts
per
second
(cps)
and
is
the
basic
unit
for
all
readout
displays.
This
average
is
also
corrected
for
detector
dead
time
(parameter
DT).
The
average
(AVG)
is
divided
by
the
calibration
constant
(parameter
CC)
(see
table
3)
and
the
proper
factors,
(units,
prefix
and
suffix)
are
applied,
converting
the
cps
to
the
radiation
units
selected.
This
is
performed
and
displayed
every
2.0
seconds.
The
calibration
is
performed
by
adjusting
the
CC
and
DT
values
so
that
the
rate
meter
reading
agrees
with
the
radiation
intensity
at
the
detector.
Note
that
the
dead
time
correction
is
applied
to
the
average
before
CC.
At
lower
count
rates,
this
correction
is
insignificant.
Refer to the table for the following:
(1)
Set
the
instrument
to
Inquiry/Calibration
Mode
(discussed
in
section
Ш.С.).
(2)
Set
the
high
voltage
and
input
sensitivity
to
suggested
values
for
detector
being
calibrated.
(3)
Set
"CC="
and
"DT"
equal
to
nominal
values
for
detector
being
used.
(Refer
to
detailed
operation,
section
IILc.
,
if
necessary.)
(4)
Select
the
"CC="
parameter.
The
current
rate
meter
reading
is
always
displayed
on
the
bottom
line
of
the
LCD
(this
applies
to
all
parameters,
DT,
HV,etc.).
(5)
Expose
the
detector
to
the
radiation
field
indicated
under
"set
CC
at"
and
adjust
"CC="
until
the
"rate
meter
reading"
matches
the
field
strength.
Note
that
increasing
the
value
of
"СС"
will
decrease
the
"rate
meter
reading"
and
decreasing
"CC"
will
increase
the
"rate
meter
reading."
See
table
3.
(6)
Select
the
"DT
(SEC)"
parameter.
Expose
the
detector
to
the
field
indicated
under
"set
DT
at"
and
adjust
"DT"
until
the
"rate
meter
reading"
matches
the
field
strength.
(7)
Recheck
the
reading
taken
in
step
5.
If
not
in
agreement,
repeat
steps
5
and
6
until
both
readings
are
correct
without
having
to
vary
the
"CC"
and
"DT"
parameters.
ESP1.MAN/February 1992