From: Christopher Tunnell (tunnell@mail.utexas.edu)
Date: Wed Sep 21 2005 - 01:18:59 CDT
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
>>
>>
>
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