Re: Lead glass blocks

[beni zihlmann <bzihlman@indiana.edu>]

Hi Tim,
the radiation hard version of the lead glass we have in mind is called 
F108. It has the same
chemical composition as the non radiation hard version F8 (also referred 
to as F8-00).
The only difference is that it has a small admixture of CeO2 (Cerium 
oxide). This small chemical admixture will not alter the basic physical 
properties of the material. This admixture will however
modify the optical properties of the material. It makes it slightly 
colored (brownish) but will
prevent the formation of additional color centers due to radiation.

cheers,
Beni

Matthew Shepherd wrote:
>
> Hi Tim,
>
> No we don't need any special cooling.  We do want to maintain 
> temperature stability as much as possible though to reduce gain 
> variation of the PMTs although we have done some testing and didn't 
> find any significant temperature dependence.  (see GlueX-doc-657)
>
> -Matt
>
> On Jan 24, 2008, at 7:55 AM, Tim Whitlatch wrote:
>
>> Hi Matt,
>>
>> I spoke with Dave Kashy about the Hall B primex lead glass 
>> calorimeter. They used lead-tungsten glass and it had to be cooled in 
>> order to perform properly. Do we require any cooling for ours taking 
>> into consideration the type of material we will use for the rad hard 
>> inner layers?
>>
>> Thanks,
>>
>>       Tim
>>
>>