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Re: News on the preAmp + CDC
Hall D Electronics:
Hi All,
To clarify:
> I would also note that to date we have not used Gerard's shaper.
> He was putting a connector on for it this afternoon, but I believe that
> all of the pulses are without it.
All the scope traces shown in section 1 ("News on the preAmp") are
without shaper board (fig. 1.1-1.4). Fig. 1.5 and 1.6 in that section were
taken with the shaper board.
All the figures/plots shown in section 2 ("understanding the drift time
spectrum") were taken with the old preAmp without shaper board.
Cheers,
Yves
>
> cheers - curtis
> On Mon January 21 2008, Fernando J. Barbosa wrote:
>> Hall D Electronics:
>>
>> Hi Yves,
>>
>> It looks like you and Gerard are making quite a lot of progress with the
>> FDC. The pulses look reasonable but there is still some work left in
>> trying to understand the source of the oscillations you observed before.
>>
>> I also looked at the drift time spectra at different sampling rates that
>> you obtained. The time structure of the main pulse is similar and of the
>> order of 200 ns. There shouldn't be any aliasing as the pulse structure
>> out of the preamp is already over 10 ns. However, there seems to be some
>> reflection or after pulsing, as the 200 MSPS picture clearly shows. If
>> you are using the shaper, check if this is not an artifact from the
>> shaper. Gerard may have chosen the shaping constants based on the CLAS
>> preamp. I and Simon observed a similar characteristic with the anode
>> shaper on the FDC.
>>
>> Regards,
>> Fernando
>>
>>
>>
>> Yves Van Haarlem wrote:
>>> Hi Fernando,
>>>
>>> Gerard is now looking at the CDC setup with the new preAmp. First
>>> findings can be found on the CDC wiki (it looks much better now):
>>>
>>> http://www.jlab.org/Hall-D/software/wiki/index.php/CDC_23_01_2008
>>>
>>> ("news on the preAmp" part)
>>>
>>> Cheers,
>>> Yves
>>>
>>>
>>> /--------------------------------
>>> / Yves Van Haarlem
>>> _--~~--_ /
>>> /~/_| |_\~\ / Carnegie Mellon University
>>> |____________| / Department of Physics
>>> |[][][][][][]|:= / Wean Hall room 8404
>>> __| __ |__ \ Pittsburgh, PA 15213
>>> | ||. | == | | \ USA
>>> (| ||__| == | |) \
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>>> /__\ /__\ \ Fax.: +1 412 681-0648
>>> ~~ ~~ \-----------------------------------
>>
>
>
>
> --
> Professor Curtis A. Meyer Department of Physics
> Phone: (412) 268-2745 Carnegie Mellon University
> Fax: (412) 681-0648 Pittsburgh PA 15213-3890
> cmeyer@ernest.phys.cmu.edu http://www.curtismeyer.com/
>