Interaction of Sr90 with CaF2 and LiF chips

["Paula Gonzalez" <pgonzale@brc1.tdh.state.tx.us>]

Hello,

I am trying to better understand the reason(s) as to why LiF chips
are more sensitive to Sr90 source  than CaF2 chips.  When exposing
both chips to Cs137 (gamma emitter), CaF2 is more sensitive due to
it's higher Z and photon sensitivity.  However, with Sr90 (beta
emitter), it is the opposite.  I suspect there may be many reasons.
I realize that Sr90 energy is 546 KEV and it's daughter Y90 is 2270
KEV.    Perhaps densities are a factor.  LiF is less dense (2.601
g/cc) compare to CaF2 (3.18 g/cc) or maybe it has something to do
with the K-shells.  If you need additional information, please let me
know.

Please respond to me directly.  Thanks for your help!

Paula H. Gonzalez
Texas Department of Health
Bureau of Radiation Control
E-Mail Address:   PGONZALE@BRC1.TDH.STATE.TX.US