Instrument Repair/calibration -Reply

[Michael S Ford <MFORD@pantex.com>]

Joey,

Unless you have a well-documented basis for changing out
instrument components (with the exception of batteries), I would be
cautious in assuming that you don't need to recal.  Many people
would interpret a cable replacement as maintenance (albeit minor).

If you get reference readings on multiple scales prior to each use,
you might be on better technical footing.  A single scale reference
reading might not catch minor changes in system performance that
a cable change could introduce (e.g., impedance deltas).

I have had different experiences than Jim Kost pointed out,
especially with regard to cable lengths.  However, a great deal of that
could be attributed to instrument and cable quality.

ANSI N323A-1997 states the following:  "4.9 Calibration Frequency...
Calibrations shall be scheduled after any maintenance or
adjustment that can affect instrument performance.  Exchange of
detectors in the field shall be permitted only after a specific
procedure, such as the one described in 4.2.2, has been
documented and implemented."

My advice would be to contact your local regulator and make sure
they are comfortable with your (well-documented) practice.

v/r
Michael
*************************
Michael S. Ford, CHP
Texas Radiation Advisory Board
Address:
Radiation Safety Department
Battelle Pantex
Amarillo, TX
806.477.5727 phone
806.477.4198 fax
mford@pantex.com
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