[Halld-tracking-hw] New preamp - resending table
Yves Van Haarlem
yvhaarle at ernest.phys.cmu.edu
Fri Apr 9 11:56:36 EDT 2010
Hi Fernando,
Thank you - that was my main concern. I believe you want to keep the
mapping as simple as possible to avoid misstakes.
Best regards,
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 Fri, 9 Apr 2010, Fernando J. Barbosa wrote:
> 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
>>>> _______________________________________________
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>>>>
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