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Member States

Member States. The Creation of Particle Beams. Paul Eaton -- United States Katarzyna Werel -- Poland HST 2000 CERN, Switzerland/France. Example of a Particle Hitting a Nucleus. Scientists learn about the fundamental components of nature

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Member States

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  1. Member States HST2000

  2. The Creation of Particle Beams Paul Eaton -- United States Katarzyna Werel -- Poland HST 2000 CERN, Switzerland/France HST2000

  3. Example of a Particle Hitting a Nucleus • Scientists learn about the fundamental components of nature • Best results occur between beams that consist of one pure type of particle • By knowing what type of particles are interacting & what particles and energies are produced, conclusions are made HST2000

  4. Pipe containing a Beam • Pipes maintain a vacuum so that a particle beam can travel great distances HST2000

  5. Target Area • Particle beams are directed into various target materials to induce interactions • Beam interactions with the atoms of the target can cause “cascades” of new types of particles HST2000

  6. Particle Beam interacting w/ Hydrogen [H2] • Scenes from the inside of a Bubble Chamber • Charged particles leave a trail of bubbles after they pass through, similar to the trails left by jet airplanes HST2000

  7. Particle Beam interacting w/ Hydrogen [H2] • When particles come close enough to the nucleus of a target atom to interact, a variety of events could occur: 1. New particles could be formed. 2. Components of the original nucleus and particle could be scattered HST2000

  8. Generalized interaction pattern • The high energy particle penetrates the medium before a chance inter-action with the target medium HST2000

  9. Generalized interaction pattern: electromagnetic cascade • mass converted to energy and two photons (gamma) are produced  e HST2000

  10. Generalized interaction pattern: electromagnetic cascade • photon passes in proximity to another atom in the medium, producing an electron (e-) / positron (e+) pair e+  e- e  e+ HST2000

  11. e+ e+ e+ e+ e+ e+       e- e- e- e- e- e-       e- e- e- e- e- e- e+ e+ e+ e+ e+ e+ Generalized interaction pattern: electromagnetic cascade • this process repeats itself in a “cascading” fashion until there is not enough energy in the particles to continue e+  e- e e- e+ HST2000

  12. e+ e+ e+ e+ e+ e+ e+        e- e- e- e- e- e- e-        e- e- e- e- e- e- e- e+ e+ e+ e+ e+ e+ e+ Generalized interaction pattern: electromagnetic cascade • this process repeats itself in a “cascading” fashion until there is not enough energy in the particles to continue *Notice: Only positrons, electrons, and photons are formed HST2000

  13. K+ Generalized interaction pattern: Hadronic Cascade • The high energy particle penetrates the medium and fractures the atomic nucleus of the target medium p n + - - HST2000

  14. K+ Generalized interaction pattern: Hadronic Cascade • The high energy particle penetrates the medium and fractures the atomic nucleus of the target medium p n + - - *Note: a large variety of particles could be produced, e.g., p, n, , , , ,  HST2000

  15. K+ K+   - - e +  + e e   - - e e + + - - e e - -       Generalized interaction pattern: Hadronic Cascade • The particles that have been produced may also contain high enough energy to either fracture another nucleus or further degrade itself p n K-  *Note: a large variety of particles could be produced, e.g., p, n, , , , ,  HST2000

  16. K+ K+   - - e +  e  e + - e -   Interaction Length Of a Hadronic Cascade • The average distance a charged particle travels in a target medium before initiating a Hadronic Cascade  + e -  -  p n K- + e - -  HST2000

  17. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ Radiation Length Which results in an electromagnetic cascade • The average distance a high energy particle penetrates a medium before initiating an electromagnetic cascade e+   e+ e-  e-  e- e+ e+ e e+ e-   e- e- e+ e e- e- e+ e+ HST2000

  18. K+ K+ e+ e+ e+ e+ e+ e+ e+        e- e- e- e- e- e- e-        + e e- e- e- e- e- e- e-  - - e + - e e+ e+ e+ e+ e+ e+ e+ -     0 5 10 15 20 25 30 35 40 45 50 Radiation vs Interaction Length in Lead [Pb] e The radiation length in lead is only 0.56 cm long     - e - + p -  n K- e  e + The interaction length is 17.1 cm  HST2000 -

  19. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ Lead Target 0.4 cm in length High energy electrons and positrons will be produced p Virtually no hadrons will be produced 0 5 10 15 20 25 30 35 40 45 50 HST2000

  20. K+ K+ e+ e+ e+ e+ e+ e+ e+        e- e- e- e- e- e- e-        e- e- e- e- e- e- e-  e + - e e+ e+ e+ e+ e+ e+ e+ -   0 5 10 15 20 25 30 35 40 45 50 Radiation vs Interaction Length in Copper [Cu] The radiation length is 1.5 cm   + e  - - - - e +  p  n K- e + e - -  The hadronic length is 15.0 cm HST2000

  21. K+ K+ e+ e+ e+ e+ e+ e+ e+        e- e- e- e- e- e- e-        e- e- e- e- e- e- e-  e + - e e+ e+ e+ e+ e+ e+ e+ -   0 5 10 15 20 25 30 35 40 45 50 Length in Copper [Cu]target 40 cm Electromagnetic cascade occurs totally inside the copper target    - - e e - + + p  n K-  e + - -  The hadronic cascade begins within the target but critical energy is not reached and low level hadrons leave the target HST2000

  22. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ Lead Target 0.4 cm in length High energy electrons and positrons will be produced p Virtually no hadrons will be produced 0 5 10 15 20 25 30 35 40 45 50 HST2000

  23. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ = electrons = positrons Path of Electrons/Positrons • Most of the electrons and positrons exiting the target will be clumped together following the path of the original high energy particle 0 5 10 15 20 25 30 35 40 45 50 HST2000

  24. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ = electrons = positrons Path of Electrons/Positrons • some of the trajectories of the particles will cause them to be lost • Most of the electrons and positrons exiting the target will be clumped together following the path of the original high energy particle 0 5 10 15 20 25 30 35 40 45 50 HST2000

  25. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ = electrons = positrons Main beam is directed into a magnetic field A magnetic field, where the field direction () is pointing into the page 0 5 10 15 20 25 30 35 40 45 50 HST2000

  26. e+ e+ e+    e- e- e-    e- e- e- e+ e+ e+ = electrons = positrons Path of Electrons/Positrons 0 5 10 15 20 25 30 35 40 45 50 HST2000

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