Feature #1897
Suspect poor tracker efficiency
0%
Description
Digging into tracker efficiency for e.g. run 8593...
Files
Updated by Rogers, Chris over 6 years ago
See, for example, slide 11 of VC talk 1st December
The scripts used to produce those plots was this one:
https://github.com/chrisrogers1234/efficiency_study
For the track extrapolation you need to install this MAUS version:
https://code.launchpad.net/~chris-rogers/maus/tracking_errors
Updated by Overton, Edward over 6 years ago
- File unused_spacepoints.pdf unused_spacepoints.pdf added
I have placed a cut to require a single hit in TOF1 and a coincidence between TOF12. I have then plotted the number of spacepoints that are not used to make a track (see unused_spacepoints.pdf). This plot shows:
1. 0 missing, correctly found tracks with no-noise (or entirely missed the detector)
2. 1,2 missing, probably noise hits.
3. spike at 5 missing!! this means something which most likely hit every plane, but was not transformed into a track. This happens:
7% of hits in the upstream
15% of hits in the downstream.
Updated by Overton, Edward over 6 years ago
I remember when we looked at the tracker paper there was a dropoff in efficiency at low Pt and Pz. The plot in the tracker paper does not go below 140MeV/c because we did not expect to be running there.
In a perfect (MC) world, we did the efficiency studies for the tracker paper. I dug up(and annotated) an old plot (see attached).
As you can see we are starting to run in the Pz efficiency drop off region. From the plot I'd expect something like a 95% efficiency, so:
1. The upstream is close to being explained,
2. Downstream requires further investigation.
Updated by Overton, Edward over 6 years ago
I looked at a 240MeV run to see if things improved. The answer is they did:
Downstream efficiency is still low (96%) and the upstream efficiency is 98%. The problem is dominated by some feature the low momentum introduces.
The next step is to run a MC simulation of the BL at 140MeV, with fields like those in the channel.
Updated by Rogers, Chris over 6 years ago
- File 8681.tar.gz 8681.tar.gz added
Plots for MC and Data run 8681.
Updated by Rogers, Chris over 6 years ago
Data cards to fire a pencil beam through the downstream tracker.
Download the tarball. Then do
source /path/to/maus/env.sh tar -xzf tracker-beam-generation.tar.gz bash do_geometry.bash # download the geometry for 8681 python $MAUS_ROOT_DIR/bin/simulate_mice.py --configuration_file config.py
- MAUS does support python code in the datacards, so you can e.g. wrap the "definitions" list using a function or something if you want to loop over several events. Just watch that the number of events per spill doesnt get too big (more than 1k or so).
- You can switch off scattering using the
physics_processes
data card if you like.