Cosmic%20Ray%20Muon%20Detection

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Cosmic Ray Muon Detection

• Department of Physics and Space Sciences
• Florida Institute of Technology
• Georgia Karagiorgi
• Julie Slanker
• Advisor Dr. M. Hohlmann

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Cosmic Ray Muons

• p -gt m nm
• p- -gt m- nm

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Main goals

• Equipment setup
• Muon flux measurement
• Investigation of flux variation with
• Altitude
• Zenith angle
• Cardinal points
• Overlap area
• Investigation of count rate variation with
• Overlap area
• Separation distance between the paddles
• Investigation of doubles flux with zenith
  angle
• Muon lifetime experiment
• Air shower experiment

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Equipment

• 2 scintillation detectors developed at Fermilab
• 2 PMT tubes
• 2 PM bases
• 2 Coincidence logic boards (version 1 and
  version2)

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Scintillation Detectors

• A scintillation detector has the property to emit
  a small flash of light (i.e. a scintillation)
  when it is struck by ionizing radiation.

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Setup

• The setup is such that the counter on the DAQ
  board and the computer are recording
  coincidences, i.e. signals sent from both
  detectors at the same time

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• DAQ board resolving time
• for coincidences 160ns

• This technique
• Results in elimination of background noise
• Offers a great number of possible experiments

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I. Setting up equipment

• Plateau Measurements for PMTs
• (Procedure for finding working voltage)
• Example of a plateau curve

Onset of regeneration effects (afterpulsing,
discharges, etc)
Plateau
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Plateau measurements
For coincidences
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Plateau measurements
For coincidences
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II. Flux

• Muons reach the surface of the Earth with
  typically constant flux Fµ.
• (count rate)d2
• Fµ ?????????????????
• (area of top panel)(area of bottom panel)
• Fµ 0.48 cm-2min-1sterad-1 (PDG theoretical
  value)
• Count rate 0.585cm-2min-1 (horizontal
  detectors)
• Our experimental value 36min-1 (8 efficiency)

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III. Investigation of flux variation

• With altitude
• We collected data on the 7 different floors of
  Crawford building, on the FIT campus
• All measurements were taken at a same specific
  location on each floor, except for the one on
  floor 7.

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III. Investigation of flux variation

• With altitude
• Results

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III. Investigation of flux variation

• With zenith angle ?
• Expected result
• Fµ cos2 ?

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III. Investigation of flux variation

• With zenith angle ?
• Rotation mount for support of the setup

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III. Investigation of flux variation

• With zenith angle ?
• Results
• (7th floor Crawford)

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III. Investigation of flux variation

• With zenith angle ?
• Results
• (7th floor Crawford)

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III. Investigation of flux variation

• With zenith angle ?
• Results
• (Observatory)

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III. Investigation of flux variation

• With zenith angle ?
• Results
• (Observatory)

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III. Investigation of flux variation

• With cardinal points
• Results
• (Senior Lab)

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III. Investigation of flux variation

• With cardinal points
• Results
• (Senior Lab)

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III. Investigation of flux variation

• With cardinal points
• Results
• (Senior Lab)

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III. Investigation of flux variation

• With cardinal points
• Results
• (Senior Lab)

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III. Investigation of flux variation

• With cardinal points
• Results
• (Senior Lab)

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III. Investigation of flux variation

• With overlap area

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III. Investigation of flux variation

• With overlap area
• Results

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IV. Investigation of count rate variation

• With overlap area
• Results

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IV. Investigation of count rate variation

• With separation distance d between the two
  paddles
• Expected results count rate is proportional to
  stereo angle viewed along a specific
  direction

Rectangular arrangement top/bottom phase
constant (lxl) d varies (multiples of l)
Values calculated using Mathematica integral
output
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IV. Investigation of count rate variation

• With separation distance d between the two
  paddles
• Results

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V. Investigation of doubles flux variation

• Using the DAQ v.1 board, we recorded low energy
  (decaying) muon events on the computer.
• These events are called doubles.

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V. Investigation of doubles flux variation

• With zenith angle ?
• Results
• (Observatory)

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VI. Muon lifetime experiment

• We collected data of double events
• We plotted tdecay of an initial sample N0 of low
  energy muons
• We fit the data to an exponential curve of the
  form N(t) N0e(-t/T)
• where T muon lifetime

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VI. Muon lifetime experiment

• Results
• y -63.856 616.791e-0.4552x
• Lifetime T
• T 2.1965µs
• Tth 2.1970µs

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VI. Muon lifetime experiment

• Results
• 
  y 14.7029
  1493.09e-0.4601x
• Lifetime T
• T 2.1733µs
• Tth 2.1970µs

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VI. Muon lifetime experiment (verification)

• Results
• 
  
• Lifetime T
• T 2.1422µs
• Tth 2.1970µs

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VI. Muon lifetime experiment (verification)

• Results
• 
  
• Lifetime T
• T 2.1678µs
• Tth 2.1970µs

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IX. Air shower experiment

• In progress
• Make use of
• DAQ v.2 board GPS option
• Another 5 detector setups assembled
• during QuarkNet

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References

• http//pdg.lbl.gov/2002/cosmicrayrpp.pdf
• http//www2.slac.stanford.edu/vvc/cosmicrays/crdct
  our.html
• http//hermes.physics.adelaide.edu.au/astrophysics
  /muon/