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What are Cosmic Rays? What are Cosmic Rays? Particles bombarding Earth from outer Particles bombarding Earth from outer space space Includes protons up to heavy elements Includes protons up to heavy elements Ionic charge and energy vary greatly Ionic charge and energy vary greatly

What are Cosmic Rays?

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What are Cosmic Rays?. Particles bombarding Earth from outer space Includes protons up to heavy elements Ionic charge and energy vary greatly. Cosmic Ray Detector. Jason Alicea University of Florida Dr. Muga Nuclear Chemistry Dept. Outline. Detector overview What I did Detector test - PowerPoint PPT Presentation

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Page 1: What are Cosmic Rays?

What are Cosmic Rays?What are Cosmic Rays?

Particles bombarding Earth from outer Particles bombarding Earth from outer spacespace

Includes protons up to heavy elementsIncludes protons up to heavy elements Ionic charge and energy vary greatlyIonic charge and energy vary greatly

Page 2: What are Cosmic Rays?

Cosmic Ray DetectorCosmic Ray Detector

Jason AliceaJason Alicea

University of FloridaUniversity of Florida

Dr. Muga Dr. Muga

Nuclear Chemistry Dept.Nuclear Chemistry Dept.

Page 3: What are Cosmic Rays?

OutlineOutline

Detector overviewDetector overview What I didWhat I did• Detector testDetector test• Scattering chamber designScattering chamber design

Conclusion-What next?Conclusion-What next? Questions?Questions?

Page 4: What are Cosmic Rays?

Cosmic Ray Detector Measures...Cosmic Ray Detector Measures...

Nuclear charge (Z)Nuclear charge (Z) EnergyEnergy VelocityVelocity MassMass Ionic chargeIonic charge

Page 5: What are Cosmic Rays?

Detector ComponentsDetector Components

Thin film detector (TFD, measures Thin film detector (TFD, measures luminescence)luminescence)• Thin scintillator filmThin scintillator film• Photomultiplier tubesPhotomultiplier tubes

Solid state detector (SSD, measures Solid state detector (SSD, measures energy)energy)

SSDSSDParticlesParticles

Photomultiplier tubesPhotomultiplier tubes

Thin filmThin film

Page 6: What are Cosmic Rays?

Why Measure Luminescence?Why Measure Luminescence?

Luminescence-Energy curves are Luminescence-Energy curves are unique for each atomic number Z.unique for each atomic number Z.

ZZ

ZZ

ZZ

11

22

33

EnergyEnergy

Lum

ines

cenc

eLu

min

esce

nce

Page 7: What are Cosmic Rays?

ZZ

ZZ

ZZ

11

22

33

EnergyEnergy

Lum

ines

cenc

eLu

min

esce

nce

Data PointData Point

Atomic # ofAtomic # of ParticleParticle

Atomic number of particle corresponds Atomic number of particle corresponds to the curve data point lies on.to the curve data point lies on.

Why Measure Luminescence?Why Measure Luminescence?

Page 8: What are Cosmic Rays?

What About Other 3 Properties?What About Other 3 Properties?

Velocity: divide distance between thin Velocity: divide distance between thin film and SSD by time recorded between film and SSD by time recorded between signalssignals

From measured energy & velocity, From measured energy & velocity, mass is easily calculatedmass is easily calculated

Ionic charge: compare luminescence & Ionic charge: compare luminescence & velocity after each of several thin filmsvelocity after each of several thin films

Page 9: What are Cosmic Rays?

What Did I Do?What Did I Do?

Fabricated a thin film, which was used Fabricated a thin film, which was used in testing the detector.in testing the detector.

Recorded response of thin film and Recorded response of thin film and SSD to fission fragmentsSSD to fission fragments

Designed scattering chamberDesigned scattering chamber

Page 10: What are Cosmic Rays?

Detector TestDetector Test

Used newly fabricated thin filmUsed newly fabricated thin film Test particles were californium (Cf) Test particles were californium (Cf)

fission fragmentsfission fragments Measured response from thin film and Measured response from thin film and

solid state detector.solid state detector. Computer recorded luminescence and Computer recorded luminescence and

energy data.energy data.

Page 11: What are Cosmic Rays?

Solid State Detector ResponseSolid State Detector Response

0

4

8

12

16

20

1 18 35 52 69 86 103 120 137 154 171 188 205 222 239 256

Energy

Co

un

ts

Good signal since peak is narrow.Good signal since peak is narrow.

Page 12: What are Cosmic Rays?

0

4

8

12

16

20

1 18 35 52 69 86 103 120 137 154 171 188 205 222 239 256

Luminescence

Co

un

ts

Thin Film ResponseThin Film Response

Peak is too wide--results in Peak is too wide--results in uncertainty in Z determinationuncertainty in Z determination

Page 13: What are Cosmic Rays?

Scattering Chamber: Why?Scattering Chamber: Why?

Beam from Van de Graaff accelerator is Beam from Van de Graaff accelerator is too strong for SSD and electronicstoo strong for SSD and electronics

SSD can be damaged and electronics SSD can be damaged and electronics overloadedoverloaded

By scattering the beam off a foil By scattering the beam off a foil (Rutherford scattering), intensity will be (Rutherford scattering), intensity will be adequately reducedadequately reduced

Page 14: What are Cosmic Rays?

Design RequirementsDesign Requirements

Scatter through angles between 0 and Scatter through angles between 0 and 60 degrees60 degrees

Chamber must accommodate at least 3 Chamber must accommodate at least 3 scattering foilsscattering foils

Must be kept at vacuum pressure Must be kept at vacuum pressure

Page 15: What are Cosmic Rays?

Final DesignFinal DesignPlunger to raise/Plunger to raise/lower foilslower foils

FixedFixedCylinderCylinder

Scattering Foils (5)Scattering Foils (5)Beam Pipe to Beam Pipe to DetectorDetector

Beam Pipe toBeam Pipe toAcceleratorAccelerator

Rotating Rotating CollarCollar

Page 16: What are Cosmic Rays?

What Next?What Next?

Improvements are underway to Improvements are underway to strengthen thin film signalstrengthen thin film signal• Copper thin film?Copper thin film?

Design of scattering chamber is Design of scattering chamber is complete, construction is anticipatedcomplete, construction is anticipated

If perfected, detector would be an If perfected, detector would be an excellent candidate for a space mission, excellent candidate for a space mission, which is the ultimate goal.which is the ultimate goal.

Page 17: What are Cosmic Rays?

Questions?Questions?