HV plateau

[Yves Van Haarlem <yvhaarle@ernest.phys.cmu.edu>]

Hall D Electronics:

Hi All,

I made a HV curve by counting the tracked cosmics i obtain in a certain 
time window (40'). The results are in top of the usual CDC ASIC tests 
page:

http://www.jlab.org/Hall-D/software/wiki/index.php/ASIC_design_optimizations

One can see a plateau starting at 1750 V.

Cheers,
 	Yves

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On Wed, 9 Apr 2008, Fernando J. Barbosa wrote:

> Hi Yves,
>
> I could not find anything physically wrong or bad with channel 16 that could 
> have caused this failure. It may have been due to assembly as this package is 
> not sealed.
>
> Regards,
> Fernando
>
> Yves Van Haarlem wrote:
>> Hi Fernando,
>> 
>> Very nice that you found the problems. I guess the bad solder joints were 
>> good when I got the interposer and became bad after a while - I am not so 
>> worried about that. But channel 16 on the preAmplifier died at some point - 
>> you can see it dying (on March 6, 2008) in the data. As far as I remember 
>> we did not do anyting to the pre-Amplifier on that day but it is already a 
>> month ago. Maybe you have an idea what could have damaged the pre-amplifier 
>> because it should be avoided in the future.
>> 
>> Cheers,
>>     Yves
>> 
>>
>>                           /--------------------------------
>>                          /   Yves Van Haarlem
>>        _--~~--_         /
>>      /~/_|  |_\~\      /      Carnegie Mellon University
>>     |____________|    /        Department of Physics
>>     |[][][][][][]|:= /          Wean Hall room 8404
>>   __| __         |__ \            Pittsburgh, PA 15213
>>  |  ||. |   ==   |  | \           USA
>> (|  ||__|   ==   |  |) \
>>  |  |[] []  ==   |  |   \           Tel.:   +1 412 268-6949
>>  |  |____________|  |    \                  +1 412 641-9252
>>  /__\            /__\     \          Fax.: +1 412 681-0648
>>   ~~              ~~       \-----------------------------------
>> 
>> On Wed, 9 Apr 2008, Fernando J. Barbosa wrote:
>> 
>>> Hi Yves,
>>> 
>>> I verified that the interposer had some bad solder joints and these have 
>>> been fixed. The one you have should be good.
>>> 
>>> I checked the amplifier and indeed channel 16 was not working. Further 
>>> tests revealed that the ASIC A input (for negative going signals or 
>>> anodes) has been damaged. The B input (for positive going signals or 
>>> cathodes) works fine.
>>> 
>>> Because I don't have additional preamp cards, I suggest that Gerard send 
>>> you his preamp and I will send him yours, which he can use for his tests. 
>>> I will ask Elke for additional funds to produce a few more preamp cards 
>>> (we have a few ASICs left).
>>> 
>>> Gerard, let us know if if this works for you.
>>> 
>>> Regards,
>>> Fernando
>>> 
>