From: Stephen Jacob Sekula (sekula@mit.edu)
Date: Wed Sep 21 2005 - 00:19:43 CDT
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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