>    Currently, we have 4 zones of photo multiplier tubes to detect
> the smallest photon count possible in the event of an arc or starting
>  of one.

>   As some of you may guess, these littler dears are starting to become a
>  relic and are now doing research to replace them with a
>  solid state approach...

>   Our current systems use 8 and 12 stage units, I think the 8 stage
> units are actually enough sensitivity..

>  Looking at the link below, have any of you had experience with these
> types of Photon counter components? Over exposure side effects etc.

> http://www-conf.kek.jp/PD07/Conference-PD07/Oral/5-slides-0-PD07_HPK_...

>>  We're starting to do some research to replace the existing
>>  Photo Multiplier tubes used in the vessels of SF6 gas where
>>  very high voltages are created.(5Mev). etc...

>>    Currently, we have 4 zones of photo multiplier tubes to detect
>> the smallest photon count possible in the event of an arc or starting
>>  of one.

>>   As some of you may guess, these littler dears are starting to become a
>>  relic and are now doing research to replace them with a
>>  solid state approach...

>>   Our current systems use 8 and 12 stage units, I think the 8 stage
>> units are actually enough sensitivity..

>>  Looking at the link below, have any of you had experience with these
>> types of Photon counter components? Over exposure side effects etc.

>> http://www-conf.kek.jp/PD07/Conference-PD07/Oral/5-slides-0-PD07_HPK_...

> They're interesting in that they let you keep track of the number of
> photons in a pulse.

> APDs in general have a very narrow dynamic range compared with
> PMTs--they have far, far higher dark count rates and saturate much
> sooner.  These segmented ones are better, and are a lot more rugged, but
> still won't touch a PMT for dynamic range.

> Cheers

> Phil Hobbs

>> Jamie wrote:

>>>  We're starting to do some research to replace the existing
>>>  Photo Multiplier tubes used in the vessels of SF6 gas where
>>>  very high voltages are created.(5Mev). etc...

>>>    Currently, we have 4 zones of photo multiplier tubes to detect
>>> the smallest photon count possible in the event of an arc or starting
>>>  of one.

>>>   As some of you may guess, these littler dears are starting to become a
>>>  relic and are now doing research to replace them with a
>>>  solid state approach...

>>>   Our current systems use 8 and 12 stage units, I think the 8 stage
>>> units are actually enough sensitivity..

>>>  Looking at the link below, have any of you had experience with these
>>> types of Photon counter components? Over exposure side effects etc.

>>> http://www-conf.kek.jp/PD07/Conference-PD07/Oral/5-slides-0-PD07_HPK_...

>> They're interesting in that they let you keep track of the number of
>> photons in a pulse.

>> APDs in general have a very narrow dynamic range compared with
>> PMTs--they have far, far higher dark count rates and saturate much
>> sooner.  These segmented ones are better, and are a lot more rugged,
>> but still won't touch a PMT for dynamic range.

>> Cheers

>> Phil Hobbs

> Interesting.
>    We were actually doing this to detect the presents of the smallest
> amount. I really don't think we need the dynamic range a PMT offers
>  in this case. But maybe the range is needed for detection of small
> counts of photons ?

>   We may get a few of these to perform some testing.

>  Thanks.

>> Phil Hobbs wrote:

>>> Jamie wrote:

>>>>  We're starting to do some research to replace the existing
>>>>  Photo Multiplier tubes used in the vessels of SF6 gas where
>>>>  very high voltages are created.(5Mev). etc...

>>>>    Currently, we have 4 zones of photo multiplier tubes to detect
>>>> the smallest photon count possible in the event of an arc or starting
>>>>  of one.

>>>>   As some of you may guess, these littler dears are starting to
>>>> become a
>>>>  relic and are now doing research to replace them with a
>>>>  solid state approach...

>>>>   Our current systems use 8 and 12 stage units, I think the 8 stage
>>>> units are actually enough sensitivity..

>>>>  Looking at the link below, have any of you had experience with these
>>>> types of Photon counter components? Over exposure side effects etc.

>>>> http://www-conf.kek.jp/PD07/Conference-PD07/Oral/5-slides-0-PD07_HPK_...

>>> They're interesting in that they let you keep track of the number of
>>> photons in a pulse.

>>> APDs in general have a very narrow dynamic range compared with
>>> PMTs--they have far, far higher dark count rates and saturate much
>>> sooner.  These segmented ones are better, and are a lot more rugged,
>>> but still won't touch a PMT for dynamic range.

>>> Cheers

>>> Phil Hobbs

>> Interesting.
>>    We were actually doing this to detect the presents of the smallest
>> amount. I really don't think we need the dynamic range a PMT offers
>>  in this case. But maybe the range is needed for detection of small
>> counts of photons ?

>>   We may get a few of these to perform some testing.

>>  Thanks.

> What's your expected range of count rates?  Doing this sort of thing
> with no photon budget leads only to tears.

> Cheers

> Phil Hobbs