[G8b_run] Fwd: g8b TOF paddle issue
Eugene Pasyuk
pasyuk at jlab.org
Wed Mar 20 12:22:57 EDT 2013
Call-in instructions:
------------------------------------------------------------------------
Dial Toll-Free Number: 866-740-1260 (U.S. & Canada)
International Toll-Free Numbers: http://www.readytalk.com/intl
Enter 7-digit access code, 7440953 followed by #
-Eugene
----- Original Message -----
> From: "Ken Livingston" <Kenneth.Livingston at glasgow.ac.uk>
> To: "g8b run" <g8b_run at jlab.org>
> Sent: Wednesday, March 20, 2013 12:18:13 PM
> Subject: Re: [G8b_run] Fwd: g8b TOF paddle issue
>
> 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.
> >>>>>> =======================================================
> >>>>
> >> _______________________________________________
> >> G8b_run mailing list
> >> G8b_run at jlab.org
> >> https://mailman.jlab.org/mailman/listinfo/g8b_run
> >>
> > _______________________________________________
> > G8b_run mailing list
> > G8b_run at jlab.org
> > https://mailman.jlab.org/mailman/listinfo/g8b_run
>
>
> --
> =======================================================
> Ken Livingston
>
> Dept. of Physics & Astronomy, Tel: +44 141 330 6428
> University of Glasgow, Fax: +44 141 330 5889
> Glasgow G12 8QQ.
> Scotland. UK.
> =======================================================
>
> _______________________________________________
> G8b_run mailing list
> G8b_run at jlab.org
> https://mailman.jlab.org/mailman/listinfo/g8b_run
>
More information about the G8b_run
mailing list