March 30, 2006 Meeting
Thursday 30, March
1 pm CST
Dial-in: 1-510-883-7860, at the prompt enter 826763 followed by the #
sign
Attending: Tim, Dan, Matt, Ed, Chris, Stan
Agenda
1. progress reports: Chris, Dan, Stan, Matt, Bill
2. plans for P5 plots
3. other business
Reports
Energy dependence of the 2 zone detector plots from Matt. Eight
single-gamma event samples of 2,000 events each were generated with the
energy of gammas ranging from 1-8 MeV. The gammas were released
isotropically from the center of the detector. All tracking
information was kept. Aside from < 0.5% of the events (per
sample) where no trigger was recorded, all events had exactly 1
trigger. For this study, only the events with a trigger were
analysed. Below are plots of deposited energy Edep
(mc.totScintEdep), generated kinetic energy KEmc
(mc.particle.ke), reconstructed energy Erec
(ev[0].efit[0].ke), and total raw charge Q per triggered event (sum
over ev[0].pmt[i].sample[j].charge) for the 2 and 8 MeV gamma samples.
2 MeV gamma events:
8 MeV gamma events:
A gaussian fit was performed on the ratio of Erec/KEmc
and Q/KEmc, although we know that a gaussian will not
provide the best fit to the charge-based distributions.
Nevertheless, it is a simple first step to compare the response at
different energies. These fits were done for all energies, and
the mean + sigma of
each fit was plotted as a function of generated gamma energy.
The fits to Q/KEmc as a function of generated gamma KE:
The fits to Erec/KEmc as a function of generated
gamma KE:
We roughly expect a linear fit to describe these distributions as a
function of energy. However, we observe a distribution which does
not fit a linear model (shown is a quadratic).
Minutes
Chris showed some plots
here
that showed the result of his PMT angular-response bug study. He
found that in GLG4sim the optical photon was trapped by the PMT,
generated the PE, then was checked for reflection, causing too many
PE generated at high angles (above about 40 degrees from the PMT
looking direction). His fix, which Glenn is reviewing for GLG4sim,
basically reverses the order of the reflection and PE generation
code. He will make energy plots for IBD events with his fix in to
check how much it affects the signal. He also posted his
absorption
length study.
Stan is working on the SNO geometry in RAT tests. Gabriel is putting a
simple RAT geometry in the SNO MC.
Dan reported to Glenn his questions on neutron cross-sections, summarized
here,
which Glenn has passed on the Karim at Subatech. The two main issues are
(1) a change in a significant change in rate of H capture compared to Gd as
the incident neutron energy increases, and (2) a excess of roughly 20 keV
in gammas released from 155Gd capture over the maximum available energy.
Next Meeting(s)
April 3rd, collaboration phone meeting, 1:30 pm CDT.
April 13th, phone meeting.
Back to Simulation
Page.
Matthew Worcester
Last modified: Tue Apr 4 14:26 CDT 2006