[Clas_offline] more fun with GSIM

[Zhiwen Zhao]

If you use gpp with DC efficiency ON, would some inefficient DC wires 
lose tracks?

Zhiwen

On 09/01/2010 04:53 PM, Craig Bookwalter wrote:
> No problem man, this is a hard problem to explain. g12 had the target
> centered at -90 cm, that's why the vertices are so far back. A better
> way to understand it is with the pictures I attached--"input.png" is an
> event that goes in, and "output.png" is what it looks like after going
> through GSIM and a1c. As you can see, one of the tracks just disappears,
> GSIM generates no hits for it. Not sure how that happens.
>
> Kijun Park wrote:
>> Craig Bookwalter wrote:
>>> I'm not clear on what you mean by trigger time--for MC the event
>>> start time is always 0 minus the photon propogation time to the event
>>> vertex, and it's useful to keep it that way for debugging stuff like
>>> this. Along with times from the ST and and TOF, that is the only time
>>> I need for reconstruction. I think, at least.
>>>
>>> Kijun Park wrote:
>>>> Craig Bookwalter wrote:
>>>>> Hi offliners,
>>>>> I am in the middle of a study where I take real events from
>>>>> reconstructed g12 data and feed those four-vectors back through
>>>>> GSIM, with the hypothesis that since these tracks have already been
>>>>> detected by CLAS in real life, after passing through GSIM and
>>>>> reconstruction I should recover close to 100% of them. Currently I
>>>>> am having a problem with GSIM not generating DC hits for some
>>>>> tracks which pass through the DC volumes. When I look at these
>>>>> events in gsim_int, I see that GSIM propogates them along strange
>>>>> trajectories--strange because I have decays and multiple scattering
>>>>> turned off. I have a PART file with a few events exhibiting this
>>>>> problem located here:
>>>>>
>>>>> /work/clas/clasg12/craigb/tmp/gsim_feedback/clas_offline/dc_no_hits.part
>>>>>
>>>>>
>>>>> Only the first seven events in this file are examples of what I am
>>>>> having trouble with; I had to add more events to the end to get
>>>>> some BOS buffer to flush and actually write the events to file.
>>>>>
>>>>> Also, I created this file to try and get a concentrated sample of
>>>>> my troublesome events, but now when I run my gsim script on this
>>>>> file, some of them have successfully-generated hits, even though I
>>>>> have the RNDM card set. I am guessing this is because RNDM just
>>>>> sets the random seed, which means changing an event's position
>>>>> within a file changes your position within the random number
>>>>> sequence. If there's a more intelligent/convenient way to share
>>>>> this information with everyone, please let me know.
>>>>> So in short, I would appreciate it if you all might take a look at
>>>>> this with me and offer any suggestions as to why GSIM would just
>>>>> not produce DC hits for what looks like 1% of tracks. Also, if I
>>>>> use the "NOSEC 'ALL'" card this no-DC-hits behavior is enhanced by
>>>>> a factor of 2 or so. Thanks in advance.
>>>>>
>>>>> --cb
>>>>>
>>>>>
>>>> Hi Craig.
>>>> I saw you didn't use the -T in your gpp. waht is the "trigbit:
>>>> 0xffff" at HEAD bank in your dc_no_hits.gpp ?
>>>> How do you know trigger time ?
>>>> Kijun
>>>>
>>>>
>>>
>>>
>> Well, I thought your problem is out of scale of z-vertex (since I am
>> not g12 guy) from you first seven event in that file.
>> If not, could you point out your trouble from your file. Sorry for
>> slow understanding.
>> Kijun
>>
>
>
>
>
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