Kaon_LT Experiment

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h1. Hall C Commissioning Analysis Meetings

* "BlueJeans Page":https://redmine.jlab.org/projects/kltexp/wiki/BlueJeans_Information

* "Hall C Wiki Meetings Page":https://hallcweb.jlab.org/wiki/index.php/Commissioning_analysis_meetings

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h2. *Notes following-up from the Hall C Analysis meeting on 4/30/20*

"Mark's slides":https://redmine.jlab.org/attachments/download/991/ReferenceTimeStudy_May2020.pdf

"Steve's slides":

* Mark and Peter's changes

** Additional hodohit corrected times method

*** Issue is Start Time made no sense and sometimes the code was being too generous for higher rates and therefore lots of trigger accidentals.

*** New code: creates new method SetCorrectedTimes which redefines the corrected start times.

**** determines time peaks to try and get rid of accidentals that were previously allowed.

*** Old code: NTimeSum> 0 (i.e. if any hits then iterate TimeSum)

*** New code: NTimeSum> 3 (i.e. if more than 3 hits then iterate TimeSum)

**** Note that this will result in more Start Time failures, but fewer accidentals in successful Start Times

** Scin plane

*** save TDC and ADC ref time for each plane

*** changed the matching of ADC hit to TDC hit

**** if ADCrawAMP=0, now tests that hit occurred rather than skipping

**** assumes time-walk is close to zero

*** In the slides, the ADC vs TDC plot shows the structure of the timing

**** The width of the TDC is from its 25 ns resolution

**** The 3 bands of ADC are from...

***** Top: reference time, this may be the cause of weird peaks in SHMS Cherenkov (a rate dependent correction factor may fix this)

***** Middle: Mark is not sure of the cause, further investigation required.

** Reference time cuts don't need to be changed but should be cleaner to make these cuts

*** So may be useful to redo cuts for higher rate runs, but only once we need to check 1% systematics

**** Mark suggested using ref time vs coin time to apply ref time cuts

*** Peter looking into the effect of changes on ref time  

** Peter's pedestal fixes for the ref time (changes from October 2019) will be included in hcana changes.

** Mark is pushing as a new branch first to get feedback before pushing to main branch

* Steve Wood looked at the scalers because there has been some issues with very high values being read in from DAQ

** It may be some corruption with bits 

** BCM ok and no one has complained yet (Although Burcu said she has seen some of these issues)

** Coin runs are ok if HMS scalers are used 

** He has only scanned a few SIDIS runs

** This will need to be fixed for future runs but, for us, he has a few improvements he is testing.

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h2. *Notes following-up from the Hall C Analysis meeting on 5/17*

* *Notes from Dave Mack on BCM calibrations*

** The bcm constants to use for now are the same one's we're having Eric P load for the F2/EMC Pass 1 analysis at https://github.com/JeffersonLab/hallc-replay-f2xem/blob/master/PARAM/GEN/gscalers.param .

** These are from Deb's March results. The March bcm calibration was large and roughly in the middle of the run. You can see the quality of the fits in the ATTACHED.

** We haven't done a global analysis yet, nor have I resolved all discrepancies between Deb and Deepak. These values are just a +-2% place-holder since F2/EMC wanted to replay all their runs sooner rather than later.

** All the BCMs are linear down to very low currents, so the only things that affects a lumi analysis between 5 and 70 muA are:

** the offsets are uncertain to about +-0.1 muA.  (So Carbon Yield vs I can be expected to deviate by O(1)% at 10 muA.) If calibrations are stable, a global analysis will reduce this.

** my slight preference would be to use BCM4A for a lumi scan. The only bcm I would NOT use for a lumi scan is BCM4B since it was almost as noisy as the Unser signal. (eg, note the higher Chi2/ndf for this channel in Deb's plots)

* *Notes from Mark on tree variables for tracking efficiency*

** The tree variable for the tracking efficiency is H.hod.goodscinhit

** For the tracking efficiency calculated in the report file

<pre>

HMSScinGood           H.hod.goodscinhit == 1

HMSGoodBetanotrk      H.hod.betanotrack > 0.8 && H.hod.betanotrack < 1.3

HMSScinShould         HMSScinGood && HMSGoodBetanotrk && !hmsDCany_large

HMSScinShoulde        HMSScinShould && H.cal.etotnorm > 0.6&& H.cal.etotnorm < 2.0&& H.cer.npeSum > 0.5

HMSScinShouldh        HMSScinGood && H.cal.etotnorm <0.6&& H.cal.etotnorm>0.0&& H.cer.npeSum < 0.5

HMSScinDid            HMSScinShould && H.dc.ntrack > 0

HMSScinDide           HMSScinShoulde && H.dc.ntrack > 0

HMSScinDidh           HMSScinShouldh && H.dc.ntrack > 0

</pre>

** H.cal.etotnorm  is the ratio of the total calorimeter energy to the central momentum so it does not involve tracking.

** H.hod.goodscinhit is set to 1 if certain scintillator criterion are met. This code is in the method THcHodoscope::TrackEffTest

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