zinc sulfide phosphor

[Neon John <johngd@bellsouth.net>]

Can anyone suggest a source for small quantities of zinc sulfide or
Strontium Aluminate phosphor powder?  I've been searching around for
the better part of a day and can't seem to find a suitable source. 
I'm interested in its phosphorescent properties rather than as a
scintillator.  I've been asked to fabricate a gas discharge tube
that would continue to glow after the current is turned off.  This
is the application.  

Thanks
John

-- 
John De Armond
johngdSPAMNOT@bellsouth.net
http://personal.bellsouth.net/~johngd/
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html