From: Stephen Jacob Sekula (sekula@mit.edu)
Date: Wed Sep 21 2005 - 10:36:53 CDT
Hi Chris,
This is me brainstorming, too: could the primaries in later events be
secondaries from prior events? I noticed that there is a time structure in these
events; can events overlap? If so, a neutron from one event might end up being
the first thing in the next event.
Steve
Christopher Tunnell wrote:
> As I think about it more, it might also be the combination of two
> things. First, it seems like, after looking at my last e-mail's data,
> that primaries can be muons post-decay (GLG4sim specific). This makes
> sense for why the electrons (see last e-mail) are there, but if you run
> "/particle/find 13", it says muons decay into anti-electron neutrinos.
> I believe some IBD code was submitted recently. Could it be that the
> IBD code somehow enters a loop or makes an error when it generates the
> neutrons from IBD?
>
> This is me brainstorming, but I figured that you might not have thought
> this since you thought the mysterious particles were protons instead of
> neutrons. Tell me if you get any use from this reasoning and also if I
> am right about new IBD code please.
>
> Good luck,
> Chris
>
> Stephen Jacob Sekula wrote:
>
>> Hi Again,
>>
>> I did a little more investigating on this muon generation issue. I
>> replace "mu-" with "e-" everywhere in my .mac file and re-ran the
>> study. That worked perfectly - all the primaries were e-. So, it looks
>> like I need to concentrate on how the particle gun handles muons...
>>
>> Any more info would still be helpful.
>>
>> Cheers,
>> Steve
>>
>> Stephen Jacob Sekula wrote:
>>
>>> Hi Folks,
>>>
>>> I need some help. I'm trying to test my addition to the RAT event
>>> tree (I wrote a processor for the veto system, etc.). To do this, I
>>> wanted to fire 1000 "cosmic ray" muons into the cave. I wanted to
>>> sample from a spectrum that was logarithmically flat in energy
>>> (10^2-10^6 MeV) and flat in zenith angle (cosTheta -1.0 - -0.3).
>>>
>>> I tried making a HEPEVT file, as for the IBD events. This wasn't
>>> successful, so instead I generated a .mac file with lines as follows:
>>>
>>> /generator/pos/set 9 "7275.89 6585.75 10000"
>>> /generator/vtx/set 17 "mu- -0.246024 0.769951 -0.588767 270.184"
>>> /run/beamOn 1
>>> /generator/pos/set 9 "9825.88 7919.56 10000"
>>> /generator/vtx/set 17 "mu- -0.39135 -0.220177 -0.893514 145.48"
>>> /run/beamOn 1
>>> /generator/pos/set 9 "9357.36 7233.58 10000"
>>> /generator/vtx/set 17 "mu- -0.546423 0.101814 -0.831298 577776"
>>> /run/beamOn 1
>>> .
>>> .
>>> .
>>>
>>> I did this 1000 times.
>>>
>>> This should have produced 1000 events with a primary being the muon.
>>> When I look at the root file - in particular, when I scan the primary
>>> in each event (and here I might have already made a mistake):
>>>
>>> root [3] T->Scan("mcparticle.pdgcode[0]")
>>> ************************
>>> * Row * mcparticl *
>>> ************************
>>> * 0 * 13 *
>>> * 1 * 13 *
>>> * 2 * 2112 *
>>> * 3 * 2112 *
>>> * 4 * 2112 *
>>> * 5 * 2112 *
>>> * 6 * 2112 *
>>> * 7 * 2112 *
>>> * 8 * 2112 *
>>>
>>> As you can see, the first two (for example) are muons. However, the
>>> next 998 events appear to have protons as primaries.
>>>
>>> I assumed that the structure of my .mac file was the problem. So,
>>> instead, I just ran this:
>>>
>>> /generator/pos/set 9 "7275.89 6585.75 10000"
>>> /generator/vtx/set 17 "mu- 0.0 0.0 -1.0 270.184"
>>> /run/beamOn 1000
>>>
>>>
>>> But I got something similar to the above in the ROOT file.
>>>
>>> I think my fundamental problem is that I've either misunderstood the
>>> way events are generated, or that I have misunderstood how particles
>>> are counted as "primary" in these events. However, it's also possible
>>> I've made some other mistake. Any help is very welcome!
>>>
>>>
>>> By the way, I want to say that so far I've found the documentation
>>> for RAT and the wiki to be excellent. I hope the above problem isn't
>>> covered in the docs -- I thought I'd read all of it before asking
>>> this here.
>>>
>>> Regards,
>>> Steve
>>>
>>>
>>
>
-- +--------------------+-------------------------------------------+ | Stephen J. Sekula | http://www.slac.stanford.edu/~sekula | | Post-Doc | http://steve.cooleysekula.org/ | +--------------------+-----------------+-------------------------+ | MIT Laboratory for Nuclear Science | SLAC: (650)-926-8596 | +--------------------------------------+-------------------------+
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