gamma energies

[Slaback@micf.nist.gov]

If energy calibration is the interest one can
use what mother nature has graciously provided,
prompt gammas. 

A marenelli filled with water will give you the
needed thermal neutron source.  Then you have the
hydrogen 2.2 MeV line as a start.

Adding high cross-section chemicals to the water
will give you the lines characteristic for those
materials, up to 10.8 MeV (albeit at a low frequency)
for nitrogen.

You will need to do a long count, e.g, 1-12 hours,
depending on the material.  But you will not need
to worry about radiative material controls.

See Table 7.12 in the Rad Health Handbook for prominent
gammas (but only a fraction of the 16000+ in the Lone, et al
listing).

One could even do a relative efficiency determination since
the prompt gamma production all relates to the same
source, i.e., cosmic rays.  But beware of competive capture
processes.  

A little risk adds spice to life.
Lester.Slaback@NIST.gov