Beta-radiography plates

Siew Wah Lee <lee_siew_wah [at] nhb__gov__sg> writes

>Beta plate is used for recording watermarks on paper. It contains
>C14 inside a sheet of polymethyl methacrylate, and gives out Beta
>radiation. I would like to know whether people are still using it
>for imaging watermarks, as the plate do gives out radiation, i.e.
>radioactive. Also what are the health and safety considerations in
>terms of storage, handling, exposure, etc. in the conservation lab.

If the manufacturer for these plates still exists they may have an
MSDS you can look up. The radioactive material is bound within the
PMMA media, so contamination is not a big issue and Beta radiation
is not deeply penetrating, so as long as you're not sleeping with
the plates stuffed down your shorts, then the radiation is not a
great issue. Keeping the plates stored in a cabinet when not in use
would be enough to block any radiation.

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain
Private Bag 92018
Auckland 1142
New Zealand
+64 9 306 7068


                                  ***
                  Conservation DistList Instance 24:48
                  Distributed: Tuesday, April 19, 2011
                       Message Id: cdl-24-48-002
                                  ***