Re: Phase II

[George Lolos <George.Lolos@uregina.ca>]

Hi Fernardo:

Thanks for the clarification.  I recall the statement by Carl Jackson 
but somehow I had correlated it with a later part of Phase II, not the 
effort to address the gain uniformity and other more SiPM-centered 
issues that we'll be pursuing in the immediate future.  It would be 
indeed a considerable improvement in stability of SiPM response if we 
could control the temperature of  the silicon volume even down to 5-10 C 
as long as we can keep the temperature constant.    As for the Hall D 
environmental controls, I think a well cooled and dry environment is the 
best for all types of electronics. 

Have a good weekend,

George


Fernando J. Barbosa wrote:

> Hi George,
>
> Any temperature stabilization in the hall will not be able to address 
> the temperature stabilization of the SiPMs. There are lots of 
> electronics inside the solenoid and cabling and pipes will negate any 
> attempt at stabilization.
>
> At out meeting with Carl Jackson, we were told by Carl that SensL 
> would look into stabilizing the temperature of the array. That may 
> necessitate a variation on their present packaging of the array. He 
> mentioned to me that it may (most likely) require a metallic hermetic 
> package. This is all preliminary but certainly this issue needs to be 
> addressed at the SiPM level. Once this part is understood, the heat 
> needs to be removed by a cooling system similar to the one being 
> designed for the FDC electronics, using Fluorinert, for example.
>
> You also raise a good point with the hall temperature stability. We 
> need to get better information on what king of stabilization and 
> environmental controls are scheduled to go into the hall or if we need 
> to further specify those controls. This information is of importance 
> to the other detector systems, as well.
>
> Regards,
> Fernando
>
>
>
> George Lolos wrote:
>
>> Hi Elke:
>>
>> Thanks for the detailed and prompt reply.  As for me being too tired 
>> last evening, you're right.  :-) However, what confused me was not 
>> the reference to the temperature stabilization but the connection to 
>> the electronics for it.  I was with the impression that the 
>> temperature (20 C was mentioned by Elton at the meeting with Carl 
>> Jackson) will be stabilized by external means in the Hall, not by 
>> SiPM related electronics.  So clearly I have missed something because 
>> last I looked, Peltier-type cooling devices for such areas are not 
>> cheap and no off the shelf items and will create their own heat 
>> generated issue.
>>
>> Take care,
>>
>> George
>>
>>
>> Elke-Caroline Aschenauer wrote:
>>
>>>
>>>>  
>>>>
>>>>> ---> I see no mention of the integration of the temperature 
>>>>> stabilisation
>>>>>    in the electronics.
>>>>>
>>>>>     
>>>>
>>>> I am baffled by this so I must have missed something.  If we don't go
>>>> with cooling, as we all agree, how can we stabilize the effects of
>>>> temperature variations with electronics alone?
>>>>
>>>>   
>>>
>>>
>>> George, you have been also tired yesterday evening. I mix gain and 
>>> break
>>> down voltage and you mix cooling and temperature stabilisation.
>>>
>>> We have been always saying we don't want to cool to -10^oC to get 
>>> the dark
>>> counts down, but to keep the gain and dark count stable we might 
>>> have to
>>> keep the temperature stable at room temperature or slighly above. 
>>> Because
>>> even if we reach a stable temperature in the hall the situation at the
>>> location of the SiPMTs and especially from SiPMT to SiPMTs might not be
>>> stable.
>>>
>>>  
>>>
>>
>>