Re: Instrument users question

["Phil V. Egidi" <7pe@ornl.gov>]

Robert,
We use the Eberline E600, Ludlum 2360, and Ludlum 2350-1 data loggers as
well as Eberline ESP-IIs.  They are all fine instruments, but we seem to
prefer the Ludlums.  For dual-phosphor scintillation detectors we use the
Ludlum 43-89 with the 2360s.  They are lightweight and easy to use.  The
2350-1 instruments are  the "Cadillac" of instruments in my opinion.  They
will store up to 19 calibration geometries, consequently, they are harder to
program/use.  The E-600 is also good for multiple calibrations, I think they
will store 3 different sets of calibration parameters.  The ESP-II
instruments are not as well-liked by the techs - they don't like the small
button array because they are not easy to use while wearing gloves.

For calibration purposes, we have adopted the use of 150 cm^2 sources (I
recommend using Amersham).  We develop efficiencies for Tc-99, Cl-36, and
Sr/Y-90 beta and Th-230 and Pu-239 for alpha, preferably 3-point for each
(5K, 50K, 100K dpm-ish).  For field work surveying for uranium, we use the
Cl-36 factors.  Check with NUREG 1507 for more information on calibration
conversion.  They are now suggesting that source efficiencies be developed
(backscatter, self-absorption, other confounders like dust).  By using
large-area sources and large area probes (~100 cm^2), the area correction
factor is no longer needed (except for point source stuff where we develop
conversions using button sources and the area correction factors).

For data conversion and manipulation, I still like a spreadsheet.  I set up
a file that has all the pertinent parameters.  This way, once the formulas
are input, each instrument's efficiency, Lc, Ld, MDC, background (for each
media), source efficiency, final dpm, counting error, etc. can be dealt
with. I don't suggest trying to propogate error for field measurements,
there are just too many uncertainties.  We just report counting error.  By
putting in sort fields for biased measurement locations, etc. the file can
then be sorted by room, survey unit, whatever. The the columns that aren't
needed for the reports can be hidden, and the tables built for the report.
The usual statistical tests can be performed within the spreadsheet program,
and those data can then be exported to the report and summary tables.

Phil Egidi
ORNL/GJ
7pe@ornl.gov

Robert Monsalve-Jones (Robert Monsalve-Jones) wrote:

> Hi group
> I am looking information from individuals who are using or have used the
> Eberline E600 or Ludlum 2360 meters for simultanous alpha beta counting
> and data logging.
> How easy (hard) is the instrument to use?
> What kind of efficiencies do you work with (u-238 and daughtors is
> the isotope of concern)?
> Computer software that is available to manipulat the data?
>
> Replies can be sent to
> Robert Monsalve-Jones
> email:  rmjones@itcrp.com
> vioce:  (505) 662-1200
>
> Thanks to one and all.
> RMJ