Re: Rad damage to teflon and PTFE

[Charles Thomas <u088558@pobox1663.Lanl.GOV>]

In air the dose to cause a 25% change in some one of its properties is of
the order of 1E04 -5E04 rads.  This is for Teflon and I suspect that some of
the other fluorcarbons will be about as bad.  The radiation source for this
is low LET (Gammas).  In a vacuum it is reported to be better.  I have no
idea what high LET radiation will do but I suspect it is higher.
Unfortunately my reference sources are at home not here.  I will try and
rember to send you more information from home tonight.


At 12:36 PM 2/1/96 -0600, you wrote:
>I hope someone can help with a non-HP question:
>What is the rad damage resistance of teflon and teflon-like
>materials (ie. PTFE)??
>
>We use PTFE insulators for electrical penetrations on our
>accelerator and had one fail recently. It lead to a vacuum
>leak which shutdown a beam line. Our theory is fluorine
>was liberated from radiation which attacked the insulator.
>We run a 700 MeV synchrotron with a 90 MeV LINAC injector.
>I measured 7 rad (photon and fast neutron) over one month
>(typical operating conditions) and the insulator was in place
>for about 5 years. 35 rad total seems way too small to me.
>
>Any info or ideas are welcome.
>
>Thanks,
>Jeff
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>Jeffrey Leavey                          certhp@vnet.ibm.com
>X-ray Lithography Program                         IBM Corp.
>914-892-4595                       East Fishkill, NY  12533
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
>
Charles (Tommy) C. Thomas
Los Alamos National Laboratory
The above are mine alone and probably 
are not those of LANL