[d2n-analysis-talk] BB TDC cuts

Wed May 26 10:41:03 EDT 2010

On Wed, May 26, 2010 at 10:15 AM, Brad Sawatzky <brads at jlab.org> wrote:

> On Sat, 22 May 2010, posik at jlab.org wrote:
>
> >   So I think I finally got the BB cer multihit TDCs working right. I just
> > use TString cuts for all hits in the TDC. For example the beam line side
> > has 6 hits, so I do something like
> >
> > TString tdc1_1 =
> >
> "DL.BBcerT01[Ndata.DL.BBcerT01-1]>xx&&DL.BBcerT01[Ndata.DL.BBcerT01-1]<xx"
>
> What happens when Ndata.DL.BBcerTxx==0?  Will it attempt to index with
> '-1' or do you watch for that condition prior to invoking this cut?
>

Yes, I took this condition in to account by appending the condition
Ndata.DLBBcerTxx!=0 to all 20 TDCs.

>
> > Where this is the cut for TDC 1 and the first hit. the xx are just hi
> > and low channels that I cut on. This is done for all hits, and all
> > TDCs on both the beam line and rhrs side.
> >
> > I am able to have cut on all beam line TDCs and RHRS side TDCs.
> > However in the final TDC cut we want
> >
> > TString bb_tdc = "beamline_tdc || rhrs_tdc"
> >
> > Where beamline_tdc has cuts for all hits of all the TDCs on the
> > beamline side and the rhrs has cuts for all hits of all the TDCs on
> > the rhrs side.  But when I try to make this cut I get an error saying
> > that there are too many operators. I looked over the code and every
> > thing looks fine.
> >
> > So I converted every thing to TCut rather than TString, thinking maybe
> > it was some sort of memeroy thing with ROOT and TString. I now get the
> > following error from ROOT when I try to apply the bb_tdc cut:
>
> Your TString would have to exceed many 100MB of memory before there
> would be a problem.  (That can happen, but typically only if there is an
> infinite recursion on building the string.)
>

Following the suggestion of this site
http://root.cern.ch/phpBB3//viewtopic.php?p=34643&sid=0337d028a3147d554b6b650c9474eddd
I was able to fix that problem. I think this cut is now correctly working.

>
> > Limitation: Statement too long tdc_test_2.C:166:
> > cint: Security mode 0x7:0x2 *** Fatal error in interpreter... restarting
> > interpreter ***
> > I was wondering if you had ever come across such an error?
>
> That's a new one to me...   Odds are that you're missing a parenthesis
> or something and the interpreter is trying to suck the rest of the
> script into the cut.
>
> When I have run into problems with complicated/long cuts, I have usually
> solved the problem by building the cut step by step and verifying that
> it works at each stage.  For really long cuts, I do the "divide and
> conquer" thing -- split the full cut in two and test one half.  If that
> works then the error is in the other half.  Take the bad half, split
> it in two, and test each piece.  Eventually you'll find the bug.
>

I had built this TDC cut up from one tdc cut on one hit, and gradually built
it up to all the TDCs and many hits. By doing this I was fairly confident
that my TDC cuts were interacting correctly. I have attached a text file
that shows the TDC cuts applied to BB tracks =0 and >0 and how the events
changed with the cuts. The two TDC plot sections at the bottom are just
notes for me that describe the plots of the nhits and TDC signals for each
hit.

>
> -- Brad
>
> --
> Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
> Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
> The most exciting phrase to hear in science, the one that heralds new
>  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov
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>

-- 
Matthew Posik
Email: posik at temple.edu
Temple University Physics Dept.
Office: BA-319
Office #:  215-204-1331
WebSites:
Temple:
http://quarks.temple.edu/
d2n:
http://hallaweb.jlab.org/experiment/E06-014/
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All cuts have "(DL.evtypebits&1<<2)==(1<<2)" 

TDC cut Format Key
tdc_#_hit#

==============================================
BB.tr.n>0	BB.tr==0	TDCcut
==============================================

54,768          31,612          none
185             120             tdc_4_1
835             554             tdc_4_2
916             572             tdc_4_3
163             89              tdc_4_4
0               0               tdc_4_5
0               0               tdc_4_6
317             255             tdc_14_1
81              59              tdc_14_2
7               8               tdc_14_3
533             316             tdc_15_1
207             122             tdc_15_2
42              30              tdc_15_3

33,135          13,379          beam_tdc (all beam tdc ORed)(and all hits 6 total)
12,043          4,150           rhrs_tdc (all rhrs tdc OR ed)(and all hits 3 total)
53,205          15,973          bb_tdc (all beam and rhrs OR ed)

============================================
tdc04 plots
=============================================
hit#             Color
------------  ---------------------------------
1                black
2                red
3                blue
4                violet
5                green

============================================
tdc14 plots
=============================================
hit#             Color
------------  ---------------------------------
1                black
2                red
3                blue