[Halld-tracking-hw] New preamp - resending table
Fernando J. Barbosa
barbosa at jlab.org
Fri Apr 9 10:44:23 EDT 2010
Hi Yves,
Just for clarification, the new cable should have a one-to-one
correspondence to the new preamp and the fADC125. This is HVB chs 24-1
map into new cable chs 1-24 which map into fADC125 chs 1-24. I will
re-label the new HVB chs 1-24 as well.
Best regards,
Fernando
Fernando J. Barbosa wrote:
> Hi Yves,
>
> Your table is correct.
>
> Thanks and best regards,
> Fernando
>
>
>
> Yves Van Haarlem wrote:
>> I think the formatting got weird up in previous mail:
>>
>> HV-board-ch || old-cable ch# || new cable ch# || fADC ch#
>>
>>
>> 24 || 1 || 1 || 1
>> 23 2 2 2
>> 22 3 3 3
>> 21 4 4 4
>> 20 5 5 5
>> 19 6 6 6
>> 18 7 7 7
>> 17 8 8 8
>> 16 9 17 !
>> 15 10 18
>> 14 11 19
>> 13 12 20
>> 12 13 21
>> 11 14 22
>> 10 15 23
>> 9 16 24
>> 8 17 9 ! 9
>> 7 18 10 10
>> 6 19 11 11
>> 5 20 12 12
>> 4 21 13 13
>> 3 22 14 14
>> 2 23 15 15
>> 1 24 16 16
>>
>>
>>
>> /--------------------------------
>> / 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 Fri, 9 Apr 2010, Yves Van Haarlem wrote:
>>
>>> Hi Fernando,
>>>
>>> I have a suggestion below,
>>>
>>>>> My other concern is over the mapping of the preamp channels
>>>>> through the
>>>>> cable. We are now using the new preamp and new cable with the old HV
>>>>> board. The correspondence between the numbering on the HV board
>>>>> and the
>>>>> preamp channels has changed. Is this now the final mapping?
>>>>>
>>>>> Previously we were using the cable with channels 1-8 and 17-24
>>>>> feeding into
>>>>> the shaper unit, which has 16 channels total, and then into two
>>>>> 8-channel
>>>>> fADCs. The chamber prototype is configured so that the missing 8
>>>>> channels
>>>>> correspond to the straws along 2 sides of the chamber; the two
>>>>> groups of 8
>>>>> channels in use correspond to two blocks of 8 straws, one above
>>>>> the other.
>>>>> With the new cable it seems that we now have access to the 8
>>>>> channels which
>>>>> were missing before (along the edge), but since we only have 16
>>>>> channels
>>>>> from the shaper, we have lost access to one block of 8 straws.
>>>>> This makes
>>>>> cosmic ray tracking much slower, since we are looking for tracks
>>>>> passing
>>>>> through at least 4 straws. This is hard to explain without a
>>>>> diagram but
>>>>> the effect is that the configuration of our available channels is
>>>>> much less
>>>>> as efficient than before. This will be solved when we have a
>>>>> 72-channel
>>>>> fADC; alternatively we could just use the old cable until the new
>>>>> fADC is
>>>>> available.
>>>>
>>>> The old preamps (also designed for 24-channels) had only two chips
>>>> installed
>>>> (on top) because the ASIC package was not reliable for assembly on
>>>> the bottom
>>>> (it had a removable lid in case we needed to probe the die). The
>>>> preamp card
>>>> has channels 1-8 from one chip on top, 9-16 from bottom chip and
>>>> 17-24 from
>>>> the second chip on top. Because of the 16-channel readout on the
>>>> shaper, the
>>>> cable (old cable) was modified at the ERNI connector (connects to
>>>> preamp) to
>>>> read channels 1-8 and 17-24. This is the reason for what you
>>>> observe with the
>>>> new cable. This won't be the case with the 72-ch fADC125 because it
>>>> reads
>>>> from all 24 channels on a preamp card. Yes, please you use the old
>>>> cable with
>>>> the new preamp and shaper for your immediate tests and then use the
>>>> new cable
>>>> when the 72-ch fADC125 becomes available (late April).
>>>
>>> Once it is decided which group of 8 channels goes where on the cable
>>> (between HV-board and fADC), could you modify the labeling of the
>>> channels
>>> on the HV board so that channel 1 -> 24 on the HV-board corresponds to
>>> channel 1 -> 24 on the fADC (or 25 -> 48; or 49 -> 72). We might
>>> avoid a
>>> lot of confusion in the future.
>>>
>>> The difference in mapping between old and new cable in a table:
>>>
>>>
>>> Ch# on HV board || ch# on old cable || new cable || fadc#
>>> 24 || 1 || 1 || 1
>>> 23 2 2 2
>>> 22 3 3 3
>>> 21 4 4 4
>>> 20 5 5 5
>>> 19 6 6 6
>>> 18 7 7 7
>>> 17 8 8 8
>>> 16 9 17 !
>>> 15 10 18
>>> 14 11 19
>>> 13 12 20
>>> 12 13 21
>>> 11 14 22
>>> 10 15 23
>>> 9 16 24
>>> 8 17 9 ! 9
>>> 7 18 10 10
>>> 6 19 11 11
>>> 5 20 12 12
>>> 4 21 13 13
>>> 3 22 14 14
>>> 2 23 15 15
>>> 1 24 16 16
>>>
>>>
>>> So the possition of two chips have been swapped on the cable, was this
>>> deliberate?
>>>
>>>
>>> Best regards,
>>> Yves
>>> _______________________________________________
>>> Halld-tracking-hw mailing list
>>> Halld-tracking-hw at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/halld-tracking-hw
>>>
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