Measurements with Micromegas Detector Prototypes for the Atlas

Myon System

Anna Ravensburg and Pascal GrobeckerCERN Internship 08.04. – 19.04.2013

http://www.atlas.ch/photos/muons-tgc.html

Micromegas

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The ATLAS - Detector

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*http://core.physicsinfo.co.uk/filestore/104/atlas.jpg

Task: To build Myon-Detectors (blue) which work fasterTime: About 5 years

Setup of a Particle Detector

4+

-+

Argon

Electric Field Particle

-+

-

Avalanche-Effect

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-+

Argon

Electric Field Particle

-+

-

- +

Micro-Mesh Gaseous Detector

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Changed from http://en.wikipedia.org/wiki/File:MMPrincipe.png

Problems at ATLAS with Micromegas

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Dust between Mesh and Strips

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Changed from http://en.wikipedia.org/wiki/File:MMPrincipe.png

Irragularities of the Electric Field

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Our tasks

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Building a Micromegas Detector

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Gas in

Gas out

Preamplifier

Fe55

Building a Setup for Measurements

Oscilloscope

To Power Supply

To Amplifier

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Building a Setup for Measurements

A Strips: +534VB Drift: -300V

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Our Measurements

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Our Measurements

36 86 136 186 2360

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Fe55: radioactive source

6 keV

Ar: Excitation

Peakpositiony x 1 2 3 4 5

1 129 153 169 175 1502 144 159 169 172 1563 154 168 167 170 1644 168 176 168 171 1565 165 171 168 164 150

Deviation from averagey x 1 2 3 4 5

1 20.49% 5.70% 4.17% 7.86% 7.54%2 11.24% 2.00% 4.17% 6.02% 3.85%3 5.08% 3.55% 2.93% 4.78% 1.08%4 3.55% 8.48% 3.55% 5.40% 3.85%5 1.70% 5.40% 3.55% 1.08% 7.54%

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Building a Micromegas Detector

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Gas in

Gas out

Preamplifier

Fe55

Full Width at Half Maximum (FWHM)y x 1 2 3 4 5

1 64 42 46 48 482 57 40 43 45 583 62 44 48 46 524 59 45 47 49 555 65 51 44 48 55

1836 86 136 186 2360

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Half MaximumFWHM

Gain Curve

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460 470 480 490 500 510 520 530 54010

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Voltage

Peak

posi

tion

Measurement of cosmic radiation

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Setup

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Scintillators

Lead

Micro-megas

Our Measurements

22Fit Panel

ConsoleData of a Micro-megas detector with fitting line

Comparision of different Detectors

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Conclusion

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Thank you for giving us the chance to come to CERN and have 12 great days! 25