FlowStar2 LB 514
6. Validation using 3H- und 14C-Test sources
53
could give higher values due to the exposure to daylight. After the
prerun time the measurement starts automatically.
Measurement
Time
Defines the measuring time for the validation (format hh:mm:ss).
Tolerance Threshold
This is the threshold in % (+/-) which defines if a validation is
passed. If the variation of the measured value and the nominal
value is outside of the tolerance threshold the validation is failed.
Rand. Error f. Background
When running a background validation the statistical error is an
important criteria. If the statistical error of a validation measure-
ment is higher than specified, the validation is failed although. Sta-
tistical errors around 1% at background measurements require a
measuring time of at least 1 hour.
Validation Cycle
Defines the time between two validations. Every successful vali-
dation changes the date for the next validation accordingly by the
defined amount of days.
Validation Mode
strict
When the box is checked the instrument gives an error message
when the validation is due. The instrument cannot be used for
measurements.
If the box is unchecked only a
status message appears („Validation
is due“ and the instrument can be used.
Last Validation
Shows the date oft he last successful validation.
Next Validation
Shows the date when the next validation should be performed. The
date can be modified since every validation (e.g. 3H and 14C) in-
creases the date which could lead to a wrong date.
Measured value
The individual test sources may differ from each other up to ±10%. There-
fore, only the results from the same test source are comparable. Write
down the number of the test source. When using a test source with a dif-
ferent serial number than the previously used one, an error message oc-
curs.
The averaged count rate is used. The nominal values are corrected for the
half live automatically.
Please note that results are comparable only when
a)
using the same test source,
b)
the test source is not being modified (dirt etc.).
Test measurements should be performed continuously and regularly (e.g.
once a year). In case of permanent validatiuon failure, please contact your
local service department.
