simulating the effects of wire sag in atlas’s monitored drift tubes ashley thrall, vassar college...
TRANSCRIPT
![Page 1: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/1.jpg)
Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes
Ashley Thrall, Vassar College ‘04
Dan Levin, Mentor
REU Presentations August 5, 2004
![Page 2: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/2.jpg)
Monitored Drift Tubes in ATLAS
½ length of a football field
8 Stories
~ 4-6 m
![Page 3: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/3.jpg)
Why Muons?
• Decay products from other particles that are of interest:
H →Z Z*→ µ-µ+µ-µ+
• Can reconstruct a muon track to determine its momentum and therefore its invariant mass
• Can use its invariant mass to determine the mass of the parent particle
![Page 4: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/4.jpg)
Drift Tube
Aluminum tube: rinner= 1.46 cm
router =1.5 cm
Gold-plated Tungsten wire
r = 25μm
V= 3080 V
Stretched by 350g
of tension
Gas Mixture:
93.0% Ar , 7% CO2
Pressure: 3 bar
![Page 5: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/5.jpg)
Drift Tube
Tube Cross-Section
Muon Track
Electrons drifting toward wire
Aluminum tubeTungsten Wire
![Page 6: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/6.jpg)
• Factors that influence the resolution of chambers through the time-space conversion:– Chemical:
• Temperature• Pressure• Gas Mixture• Contaminants
– Geometrical:• Tube/Wire• Position of Tube• Temperature• Wire Position in Tube: Wire Sag
– Electronics:• Electronics Response
Motivation?
![Page 7: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/7.jpg)
• Gravitational Sag: ~470µm for 5.9m tube
• Electromagnetic Attraction: ~28µm for 5.9m tube with 3080V
• Sag destroys symmetry – not compensated for in Endcap chambers
The Problem: Wire Sag
T
LD
L
X
L
X 22
2
2
32
81.94
X= position along tube
L= length of tube
ρ = density of wire
D = diameter of wire
T= pre-stretched tension
![Page 8: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/8.jpg)
• Distance electrons travel
• Electric Field
Factors Influenced by Sag
![Page 9: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/9.jpg)
Goals
• Overall Objective: – to be able to parameterize the effects of wire sag in
ATLAS’s monitored drift tubes based on the position of the event along the tube
• Objective of this Project:– To simulate the effects of wire sag on muon drift time
spectra using the Garfield software program– To quantitatively measure these effects– To compare these results with cosmic ray data that
Divine analyzes
![Page 10: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/10.jpg)
Preliminary Study: Horizontal vs. Vertical Tracks
Vertical Tracks with 472 µm Sag
Horizontal Tracks with 472 µm Sag
![Page 11: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/11.jpg)
Drift Time Spectra
Drift Time (ns)
dN/d
t
![Page 12: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/12.jpg)
Drift Time Spectra
Drift Time (ns)
dN/d
t
![Page 13: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/13.jpg)
Drift Time Spectra
Drift Time (ns)
dN/d
t
![Page 14: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/14.jpg)
Maximum Drift TimesRun Drift
Time 1 (ns)
Error Drift Time 2
(ns)
Error
No Sag 696.937 1.66387 --- ---
Vertical Tracks with 472 µm Sag
699.374 1.76805 --- ---
Horizontal Tracks with 472 µm Sag
650.476 4.80863 768.188 2.21768
![Page 15: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/15.jpg)
Why the Double Tail?Impact Parameter Plot
Max
imum
Dri
ft T
ime
(µs)
Impact Parameter (cm)
![Page 16: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/16.jpg)
Comparison with Cosmic Ray Data: No Sag
Drift Time (ns)
dN/d
t
Drift Time (ns)
dN/d
t
Garfield Data Cosmic Ray Data
Maximum Drift Time:
696.937 +/-1.66387
Maximum Drift Time:
671.215 +/- 1.21142
![Page 17: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/17.jpg)
Comparison with Cosmic Ray Data: Middle of Tube (Max Sag)
Drift Time (ns)
dN/d
t
Drift Time (ns)
dN/d
t
Garfield Data:
Horizontal Tracks
472µm Sag
Cosmic Ray Data:
323 µm Sag
Maximum Drift Times:
650.476 +/-4.80863
768.188 +/-2.21768
Maximum Drift Times:
637.784 +/-1.93216
717.928 +/-1.9416
![Page 18: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/18.jpg)
Conclusions
Future Work
• Wire sag has a significant effect on drift time spectra and maximum drift times for tracks oriented in particular directions with respect to sag
• Program Garfield to randomly sample from the distribution of cosmic rays
• Perform simulations that correspond to the positions at which data was taken
• Quantitatively compare these results to the cosmic ray data
![Page 19: Simulating the Effects of Wire Sag in ATLAS’s Monitored Drift Tubes Ashley Thrall, Vassar College ‘04 Dan Levin, Mentor REU Presentations August 5, 2004](https://reader035.vdocument.in/reader035/viewer/2022062719/56649ef25503460f94c0439f/html5/thumbnails/19.jpg)
Acknowledgements
• Dan Levin, Rachel Avramidou, Rob Veenhof, Divine Kumah
• National Science Foundation, University of Michigan REU Program, CERN Summer Student Program