[G8b_run] Fwd: g8b TOF paddle issue
Ken Livingston
Kenneth.Livingston at glasgow.ac.uk
Wed Mar 20 12:18:13 EDT 2013
Hi All,
I've made a very brief meeting page at
https://clasweb.jlab.org/rungroups/g8/wiki/index.php/Mar_26,_2013
Can you please upload any relevant files (eg Brian's plots).
Cheers,
Ken
On 20/03/13 16:01, Eugene Pasyuk wrote:
> So far 7 people responded to doodle poll. The earliest best time slot at the moment is Tuesday 12:30 JLab time.
>
> -Eugene
>
> ----- Original Message -----
>> From: "Eugene Pasyuk" <pasyuk at jlab.org>
>> To: "g8b run" <g8b_run at jlab.org>
>> Sent: Tuesday, March 19, 2013 4:36:38 PM
>> Subject: [G8b_run] Fwd: g8b TOF paddle issue
>>
>>
>>
>>
>> ----- Forwarded Message -----
>> From: "Eugene Pasyuk" <pasyuk at jlab.org>
>> To: "Michael Dugger" <dugger at jlab.org>
>> Cc: "Ken Livingston" <Kenneth.Livingston at glasgow.ac.uk>, "Franz
>> Klein" <fklein at jlab.org>, "Brian Vernarsky" <soulish at gmail.com>,
>> "Volker Crede" <crede at fsu.edu>, "Patrick Collins"
>> <pcollins at jlab.org>, "Charles Hanretty" <hanretty at jlab.org>
>> Sent: Tuesday, March 19, 2013 4:21:10 PM
>> Subject: Re: g8b TOF paddle issue
>>
>> Let's have a meeting. I set up doodle:
>> http://doodle.com/ycqshd8fpnda66mx
>>
>> -Eugene
>>
>> ----- Original Message -----
>>> From: "Michael Dugger" <dugger at jlab.org>
>>> To: "Volker Crede" <crede at fsu.edu>
>>> Cc: "Ken Livingston" <Kenneth.Livingston at glasgow.ac.uk>, "Franz
>>> Klein" <fklein at jlab.org>, "Brian Vernarsky"
>>> <soulish at gmail.com>, "Eugene Pasyuk" <pasyuk at jlab.org>
>>> Sent: Tuesday, March 19, 2013 3:36:51 PM
>>> Subject: Re: g8b TOF paddle issue
>>>
>>>
>>> Hi,
>>>
>>> This could be scary.
>>>
>>> From what I understand, this problem will create phi dependent
>>> inefficiencies. This will especially true for single track events.
>>> However,
>>> if an analysis uses the data to self analyze the phi dependent
>>> efficiencies (e.g. forming quantities like (Y_PARA -
>>> Y_PERP)/(Y_PARA
>>> +
>>> Y_PERP)), then the recooking of data will only help add statistics
>>> for
>>> those type of analyses.
>>>
>>> Since I have two channels of g8b that have gone through analysis
>>> review,
>>> and Volker is either finished with analysis review, or nearly so,
>>> it
>>> is
>>> important that we determine if those analysis can remain as is.
>>>
>>> If it is determined that all of the analyses must use recooked
>>> data,
>>> we
>>> need to do the recooking as soon as possible.
>>>
>>> Take care,
>>> Michael
>>>
>>> On Tue, 19 Mar 2013, Volker Crede wrote:
>>>
>>>> Hi all,
>>>>
>>>> It sounds really scary. Yes, we should meet and discuss this.
>>>>
>>>> Volker
>>>>
>>>>
>>>> On Mar 19, 2013, at 12:34 PM, Michael Dugger <dugger at jlab.org>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> Having a meeting makes sense.
>>>>>
>>>>> Take care,
>>>>> Michael
>>>>>
>>>>> On Tue, 19 Mar 2013, Ken Livingston wrote:
>>>>>
>>>>>> Hi All,
>>>>>> It does indeed look like we cooked with the version that was in
>>>>>> /home/clasg8/g8/packages/
>>>>>> where, as Brian says, we had
>>>>>> #define SC_TDC_MAX 4096
>>>>>>
>>>>>> if I look at set_env_g8b.sh see
>>>>>> export CLAS_PACK=/u/home/${RUN_USER}/g8/packages
>>>>>>
>>>>>> I think we do need to consider recalibrating the TOF and
>>>>>> recooking the data. At least starting with one coherent peak
>>>>>> setting.
>>>>>>
>>>>>> What do you all think?
>>>>>> We should at least have a meeting to discuss this.
>>>>>>
>>>>>> Cheers,
>>>>>> Ken
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 19/03/13 13:43, Franz Klein wrote:
>>>>>>> sorry, replied only to Eugene ...
>>>>>>> ----- Forwarded Message -----
>>>>>>> From: "Franz Klein" <fklein at jlab.org>
>>>>>>> To: "Eugene Pasyuk" <pasyuk at jlab.org>
>>>>>>> Sent: Tuesday, March 19, 2013 9:38:42 AM
>>>>>>> Subject: Re: g8b TOF paddle issue
>>>>>>> Yes, Eugene, I worked on the copy_pipeline.cc routine in the
>>>>>>> beginning of g9a ... mostly because the SC, EC banks took the
>>>>>>> first TDC entry from SCT, ECT instead of the one which is in
>>>>>>> the 'right' (expected) range.
>>>>>>> So maybe I'll take a look first into the g8b version of this
>>>>>>> routine as well as SCT, ECT, REF.
>>>>>>> ----- Original Message -----
>>>>>>> From: "Eugene Pasyuk" <pasyuk at jlab.org>
>>>>>>> To: "Franz Klein" <fklein at jlab.org>
>>>>>>> Cc: "Michael Dugger" <dugger at jlab.org>, crede at fsu.edu, "Brian
>>>>>>> Vernarsky" <soulish at gmail.com>, "Kenneth Livingston"
>>>>>>> <Kenneth.Livingston at glasgow.ac.uk>
>>>>>>> Sent: Tuesday, March 19, 2013 9:29:45 AM
>>>>>>> Subject: Re: g8b TOF paddle issue
>>>>>>> One thing which comes to mind is that at some point after
>>>>>>> pipeline TDC were installed we discovered that there is some
>>>>>>> issue in on-line procedure of matching TDC and ADC from SC and
>>>>>>> SCT banks and remaking of raw SC bank. The procedure was
>>>>>>> revisited and as I recall we used new matching procedure in
>>>>>>> user_ana for g9a data. May be this is the reason for g8b
>>>>>>> problem?
>>>>>>> -Eugene
>>>>>>> ----- Original Message -----
>>>>>>>> From: "Franz Klein" <fklein at jlab.org>
>>>>>>>> To: "Kenneth Livingston" <Kenneth.Livingston at glasgow.ac.uk>
>>>>>>>> Cc: "Michael Dugger" <dugger at jlab.org>, "Eugene Pasyuk"
>>>>>>>> <pasyuk at jlab.org>, crede at fsu.edu, "Brian Vernarsky"
>>>>>>>> <soulish at gmail.com>
>>>>>>>> Sent: Tuesday, March 19, 2013 9:23:00 AM
>>>>>>>> Subject: Re: g8b TOF paddle issue
>>>>>>>> Ken,
>>>>>>>> unfortunately I don't remember whether we checked or changed
>>>>>>>> the cut
>>>>>>>> on overflows. We took the code from eg3 (Joern) which assumes
>>>>>>>> TDC
>>>>>>>> entries in the range ~1000 to ~6000 (depending on particle
>>>>>>>> and
>>>>>>>> REF
>>>>>>>> signal).
>>>>>>>> However, Brian found out quite some time ago that often in
>>>>>>>> multi-track events many track candidates weren't getting into
>>>>>>>> time-based tracking due to missing timing information from ST
>>>>>>>> and/or
>>>>>>>> SC.
>>>>>>>> For sure we made the mistake to cut out all SC paddles in the
>>>>>>>> reconstruction for which the calibration didn't work out
>>>>>>>> (instead of
>>>>>>>> letting students worry about SC paddle cuts later in their
>>>>>>>> analysis). In that sense it might be a good idea to recheck
>>>>>>>> ST
>>>>>>>> and
>>>>>>>> SC calibrations and maybe rerun user_ana for some coh.edge
>>>>>>>> setting
>>>>>>>> on the farm.
>>>>>>>> Maybe as a first step, Brian should tar his source code he
>>>>>>>> copied
>>>>>>>> from the clasg8 account and we verify whether it is the code
>>>>>>>> which
>>>>>>>> was used for g8b reconstruction.
>>>>>>>> Cheers,
>>>>>>>> Franz
>>>>>>>> ----- Original Message -----
>>>>>>>> From: "Ken Livingston" <Kenneth.Livingston at glasgow.ac.uk>
>>>>>>>> To: "Brian Vernarsky" <soulish at gmail.com>
>>>>>>>> Cc: "Michael Dugger" <dugger at jlab.org>, "Eugene Pasyuk"
>>>>>>>> <pasyuk at jlab.org>, crede at fsu.edu, "Franz Klein"
>>>>>>>> <fklein at jlab.org>
>>>>>>>> Sent: Tuesday, March 19, 2013 8:18:45 AM
>>>>>>>> Subject: Re: g8b TOF paddle issue
>>>>>>>> Hi Brian,
>>>>>>>> There's certainly something funny going on there which we
>>>>>>>> need
>>>>>>>> to get
>>>>>>>> to
>>>>>>>> the bottom of.
>>>>>>>> However, I'm not sure your diagnosis is correct.
>>>>>>>> As far as I can see, when I log on to the clasg8 account cd
>>>>>>>> $CLAS_PACK
>>>>>>>> directory is set to
>>>>>>>> /home/clasg8/packages, not /home/clasg8/g8/packages/ where
>>>>>>>> you
>>>>>>>> mention
>>>>>>>> finding the header file with the old version of sc.h.
>>>>>>>> In the clasg8 account version of $CLAS_PACK/include/sc.h the
>>>>>>>> relevant
>>>>>>>> line is
>>>>>>>> #define SC_TDC_MAX 8192 /* pipeline */
>>>>>>>> Do any of the rest of you have any opinion or memory on that?
>>>>>>>> Regards,
>>>>>>>> Ken
>>>>>>>> On 18/03/13 22:03, Brian Vernarsky wrote:
>>>>>>>>> Hello all,
>>>>>>>>> In trying to finalize my results for the spin density matrix
>>>>>>>>> elements
>>>>>>>>> for the omega I have run into a serious issue with the g8b
>>>>>>>>> dataset.
>>>>>>>>> When I project out my spin density matrix elements I found
>>>>>>>>> that the
>>>>>>>>> unpolarized elements, which can be compared to previous
>>>>>>>>> experiments
>>>>>>>>> (g11a most notably), were slightly offset with respect to
>>>>>>>>> those
>>>>>>>>> previous measurements. I have shown these elements at
>>>>>>>>> previous
>>>>>>>>> CLAS
>>>>>>>>> Hadron meetings so some of you may be aware of this.
>>>>>>>>> I traced the source of my problem back to the fact that the
>>>>>>>>> phi
>>>>>>>>> distributions of the particles were skewed and this was not
>>>>>>>>> properly
>>>>>>>>> reflected in the monte carlo. Looking further into the
>>>>>>>>> issue
>>>>>>>>> I
>>>>>>>>> discovered that the start counters have a serious issue with
>>>>>>>>> detecting
>>>>>>>>> individual pions; the efficiency varies wildly from paddle
>>>>>>>>> to
>>>>>>>>> paddle.
>>>>>>>>> However, since we had a one-track trigger and I am looking
>>>>>>>>> for
>>>>>>>>> three-track events with a proton, this was not the source of
>>>>>>>>> my
>>>>>>>>> issue,
>>>>>>>>> however it could be a serious issue for anyone looking into
>>>>>>>>> single
>>>>>>>>> pion reactions. The source of my issue is particles that
>>>>>>>>> have
>>>>>>>>> a
>>>>>>>>> TOF
>>>>>>>>> paddle set to 0, indicating there is a problem with them.
>>>>>>>>> As
>>>>>>>>> you
>>>>>>>>> can
>>>>>>>>> see in the enclosed file phi_distributions_g8b.pdf the
>>>>>>>>> actual
>>>>>>>>> phi
>>>>>>>>> distribution for each particle (in black) looks to be ok,
>>>>>>>>> however
>>>>>>>>> when
>>>>>>>>> we remove the particles with TOF paddle = 0 (in red) and are
>>>>>>>>> left
>>>>>>>>> with
>>>>>>>>> just the particles with a "good" TOF paddle (in blue) there
>>>>>>>>> is
>>>>>>>>> a
>>>>>>>>> pretty severe problem, mostly for the pions.
>>>>>>>>> In looking at the TOF paddle = 0 events for the two pions
>>>>>>>>> you
>>>>>>>>> can
>>>>>>>>> notice that they are almost the exact same, whereas the
>>>>>>>>> proton
>>>>>>>>> has
>>>>>>>>> significantly less events with a "bad" TOF paddle. And
>>>>>>>>> there
>>>>>>>>> is a
>>>>>>>>> definite phi dependence to the bad events. Certainly we
>>>>>>>>> should
>>>>>>>>> expect
>>>>>>>>> some events with bad TOF paddles in every channel, however
>>>>>>>>> this is
>>>>>>>>> accounting for almost half of the total events in sector 5
>>>>>>>>> for
>>>>>>>>> the
>>>>>>>>> pions. There is no physical reason for this to be so.
>>>>>>>>> I have found the source of the problem to be in the TDCs of
>>>>>>>>> the TOF
>>>>>>>>> paddles. In the file tdcs_and_adcs_g8b.pdf I have shown the
>>>>>>>>> values
>>>>>>>>> from the TDCs and ADCs for the TOF paddles, in the order
>>>>>>>>> TDCL,
>>>>>>>>> ADCL,
>>>>>>>>> TDCR, ADCR, for the proton (top), pi+ (middle) and pi-
>>>>>>>>> (bottom),
>>>>>>>>> integrated over all paddles and sectors for one amorphous
>>>>>>>>> run
>>>>>>>>> (48133).
>>>>>>>>> The blue on each plot are "good" events and the red are
>>>>>>>>> "bad", or
>>>>>>>>> TOF
>>>>>>>>> = 0, events. It is very evident from the TDC plots for all
>>>>>>>>> particles
>>>>>>>>> that something turns on at channel 4096. I have tried to
>>>>>>>>> illustrate
>>>>>>>>> that by drawing a vertical line at 4096 on the TDC plots.
>>>>>>>>> The
>>>>>>>>> ADC
>>>>>>>>> plots show nothing out of the ordinary.
>>>>>>>>> What happened is that before the g8b run the TDCs were
>>>>>>>>> changed
>>>>>>>>> from
>>>>>>>>> a
>>>>>>>>> 12-bit system to a 16-bit system, changing the maximum
>>>>>>>>> channel
>>>>>>>>> from
>>>>>>>>> 4096 to 65536. However, this change was not made in the
>>>>>>>>> code
>>>>>>>>> as in
>>>>>>>>> the g8b cooking code (found at /home/clasg8/g8/packages/)
>>>>>>>>> the
>>>>>>>>> file
>>>>>>>>> include/sc.h we find
>>>>>>>>> #define SC_TDC_MAX 4096
>>>>>>>>> instead of 8192 like we find in other experiments after the
>>>>>>>>> TDCs
>>>>>>>>> were
>>>>>>>>> changed. (It seems that while we effectively have 65,536
>>>>>>>>> channels
>>>>>>>>> in
>>>>>>>>> practice we only use 8192.) Any particle that registered
>>>>>>>>> above
>>>>>>>>> 4096
>>>>>>>>> on a TDC was deemed a "bad" event in that TDC. If the
>>>>>>>>> particle had
>>>>>>>>> a
>>>>>>>>> "bad" TDCL but a "good" TDCR then it is still possible to
>>>>>>>>> recover
>>>>>>>>> the
>>>>>>>>> events, and vice versa, though not all particles could be
>>>>>>>>> recovered
>>>>>>>>> in
>>>>>>>>> this way. However, if both TDCs measured a value above 4096
>>>>>>>>> then
>>>>>>>>> the
>>>>>>>>> particle was deemed "bad" and assigned TOF paddle = 0.
>>>>>>>>> For a signifcant number of TOF paddles the range of TDC
>>>>>>>>> channels
>>>>>>>>> was
>>>>>>>>> from 3800-4200, though some skewed higher or lower than
>>>>>>>>> others.
>>>>>>>>> For
>>>>>>>>> paddles where the distribution was quite high as many as
>>>>>>>>> half
>>>>>>>>> of
>>>>>>>>> the
>>>>>>>>> pions were cut and a signficant number of protons were also
>>>>>>>>> cut.
>>>>>>>>> This
>>>>>>>>> led to difficulty in calibrating the paddle and so the
>>>>>>>>> entire
>>>>>>>>> paddle
>>>>>>>>> was cut. There were 31 paddles cut in g8b, more than 10% of
>>>>>>>>> the
>>>>>>>>> total
>>>>>>>>> number of paddles.
>>>>>>>>> For the pions the cut is pretty evenly distributed across
>>>>>>>>> the
>>>>>>>>> momentum
>>>>>>>>> spectrum, but for protons it cuts only events above ~550 MeV
>>>>>>>>> as can
>>>>>>>>> be
>>>>>>>>> seen in the file p_dist_bad_paddles.pdf, which shows the
>>>>>>>>> momentum
>>>>>>>>> distribution for protons that have been ascribed TOF paddle
>>>>>>>>> =
>>>>>>>>> 0.
>>>>>>>>> Now,
>>>>>>>>> this is a small fraction of the total number of proton
>>>>>>>>> events,
>>>>>>>>> but
>>>>>>>>> it
>>>>>>>>> is still significant.
>>>>>>>>> Based on all of this I think that it is imperative that we
>>>>>>>>> recook
>>>>>>>>> the
>>>>>>>>> g8b dataset. We will need to change the value of SC_TDC_MAX
>>>>>>>>> and
>>>>>>>>> then
>>>>>>>>> recalibrate the TOF paddles; hopefully the ones that were
>>>>>>>>> considered
>>>>>>>>> "good" before will not need much work, but of the ones
>>>>>>>>> considered
>>>>>>>>> "bad" before most of them can almost certainly be salvaged.
>>>>>>>>> This
>>>>>>>>> recook is necessary because it is clear that this is
>>>>>>>>> significantly
>>>>>>>>> affecting the phi and momentum distributions of all
>>>>>>>>> particles
>>>>>>>>> and
>>>>>>>>> thus
>>>>>>>>> will affect all measurements that depend on phi, momentum,
>>>>>>>>> TOF
>>>>>>>>> or
>>>>>>>>> particle ID. The plus side is that we can recover a large
>>>>>>>>> number
>>>>>>>>> of
>>>>>>>>> paddles and thus increase our statistics significantly,
>>>>>>>>> especially
>>>>>>>>> with multi-particle events. Any other minor issues that
>>>>>>>>> wouldn't
>>>>>>>>> necessitate a recook on their own can also be addressed
>>>>>>>>> before
>>>>>>>>> we
>>>>>>>>> start. And lastly I think that it would be a very good idea
>>>>>>>>> to
>>>>>>>>> include some more banks in the cooked files this time than
>>>>>>>>> we
>>>>>>>>> did
>>>>>>>>> before; to find the TDC and ADC values I had to go to the
>>>>>>>>> raw
>>>>>>>>> files
>>>>>>>>> without any PID info and then cross check between that and
>>>>>>>>> the
>>>>>>>>> cooked
>>>>>>>>> file to make sure I had the right particle, certainly the SC
>>>>>>>>> banks
>>>>>>>>> should be included in the newly cooked files.
>>>>>>>>> Let me know what you think, if you would like any additional
>>>>>>>>> information or plots just ask.
>>>>>>>>> Brian
>>>>>>>> --
>>>>>>>> =======================================================
>>>>>>>> Ken Livingston
>>>>>>>> Dept. of Physics & Astronomy, Tel: +44 141 330 6428
>>>>>>>> University of Glasgow, Fax: +44 141 330 5889
>>>>>>>> Glasgow G12 8QQ.
>>>>>>>> Scotland. UK.
>>>>>>>> =======================================================
>>>>>>>> --
>>>>>>>> ===============================================================
>>>>>>>> Franz J. Klein, Associate Professor
>>>>>>>> CUA, Department of Physics
>>>>>>>> Washington, DC 20064
>>>>>>>> office: Hannan Hall 206 phone: 202-319-6190
>>>>>>>> or: Jefferson Lab,CC F-243 phone: 757-269-6672
>>>>>>>> ---------------------------------------------------------------
>>>>>>
>>>>>> --
>>>>>> =======================================================
>>>>>> Ken Livingston
>>>>>>
>>>>>> Dept. of Physics & Astronomy, Tel: +44 141 330 6428
>>>>>> University of Glasgow, Fax: +44 141 330 5889
>>>>>> Glasgow G12 8QQ.
>>>>>> Scotland. UK.
>>>>>> =======================================================
>>>>
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--
=======================================================
Ken Livingston
Dept. of Physics & Astronomy, Tel: +44 141 330 6428
University of Glasgow, Fax: +44 141 330 5889
Glasgow G12 8QQ.
Scotland. UK.
=======================================================
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