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Cherenkov Radiation (and other shocking waves).

Cherenkov Radiation (and other shocking waves). Shock Waves May Confuse Birds’ Internal Compass. Perhaps also the ones of the fish?. http://www.newscientist.com/lastword/answers/lwa674bubbles.html http://www.pbs.org/wgbh/nova/barrier/.

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Cherenkov Radiation (and other shocking waves).

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  1. Cherenkov Radiation (and other shocking waves). Shock Waves May Confuse Birds’ Internal Compass Perhaps also the ones of the fish? http://www.newscientist.com/lastword/answers/lwa674bubbles.html http://www.pbs.org/wgbh/nova/barrier/

  2. The density effect in the energy loss is intimately connected to the coherent response of a medium to the passage of a relativistic particle that causes the emission of Cherenkov radiation. Calculate the electromagnetic energy flow in a cylinder of radius a around the track of the particle. a Define If a is in the order of atomic dimension and |la|<<1 we will then get the Fermi relation for dE/dX with the density effect. If |la|>>1 , we get (after some steps): subscript 1 : along particle velocity 2, 3 : perpendicular to Ifl has a positive real part the integrand will vanish rapidly at large distances  all energy is deposited near the track If l is purely imaginary  the integrand is independent of a  some energy escapes at infinite as radiation  Cherenkov radiation and or and we assume e real as from now on

  3. Let us consider a particle that interacts with the medium Conservation of energy and momentum The behavior of a photon in a medium is described by the dispersion relation Argon at normal density W.W.M. Allison and P.R.S. Wright RD/606-2000-January 1984

  4. 5 4 3 2 eV A particle with velocity b b=v/c in a medium with refractive index n n=n(l) may emit light along a conical wave front. The angle of emission is given by and the number of photons by

  5. cos(q) = 1/b*n m = p/b*g Dm/m = [(Dp/p)2 + (g2*tgq*Dq)2]½ set : n 1.28 (C6F14) Dp/p2 5*10-4 Dq 15 mrad L 1 cm 1/l1 -1/l2 = 1/2200 - 1/1800 (l in A) with Q=20% qmax = 38.6 o bmin = .78 p K p

  6. Threshold Cherenkov Counter Cherenkov gas Particle with charge q velocity b Spherical mirror Flat mirror Photon detector To get a better particle identification, use more than one radiator. Positive particle identification : A radiator : n=1.0024 B radiator : n=1.0003

  7. Directional Isochronous Selfcollimating Cherenkov (DISC) More general for an Imaging Detector Cherenkov radiator n=f(photon energy) N photons N=f(b) 200nm 150 (n-1)*106 b Transformation Function r=f(b,n) D(r)=f(resolution)

  8. The light cone The Cherenkov radiator Q, b The particle

  9. http://banzai.msi.umn.edu/leonardo/

  10. Hey! Did I mention TMAE to you?! Did I?!? Detector Focusing Mirror Cherenkov media e- e+ Proportional Chamber g g g Quartz Plate e e e E Photon to Electron conversion gap

  11. Particle Identification in DELPHI at LEP I and LEP II • 0.7  p  45 GeV/c • 15°  q  165° n = 1.28 C6F14 liquid p/K p/K/p K/p n = 1.0018 C5F12 gas p/h p/K/p K/p 2 radiators + 1 photodetector

  12. Particle Identification with the DELPHI RICHes Liquid RICH Cherenkov angle (mrad) Gas RICH p (GeV) From data p from L K from F D* p from Ko http://delphiwww.cern.ch/delfigs/export/pubdet4.html DELPHI, NIM A: 378(1996)57

  13. Yoko Ono 1994 FRANKLIN SUMMER SERIES, ID#27 I forbindelse med utstillingen i BERGEN KUNSTMUSEUM, 1999 More beautiful pictures (which has next to nothing to do with) Cherenkov radiation ABB.com

  14. An exact calculation of Transition Radiation is complicated J. D. Jackson (bless him) and he continues: A charged particle in uniform motion in a straight line in free space does not radiate A charged particle moving with constant velocity can radiate if it is in a material medium and is moving with a velocity greater than the phase velocity of light in that medium (Cherenkov radiation) There is another type of radiation, transition radiation, that is emitted when a charged particle passes suddenly from one medium to another. If e<1 no real photon can be emitted for an infinite long radiator. Due to diffraction broadening, sub-threshold emission of real photons in thin radiators. w02=plasma frequency 2  (electron density) If w>>w0

  15. All this for a small number? If wp2>wp1 then Qmax g-1 Total radiated power S 10-2g (eV)  which is a small number

  16. Periodic radiator for Transition Radiation. Coherent addition in point P (-1)k : The field amplitude for successive interfaces alternate in sign A(Qk) : Amplitude fk = w(R/c-t) : phase factor g = 2 104 l1 = 25 mm l2 = 0.2 mm polypropylene - air Egorytchev, V ; Saveliev, V V ;Monte Carlo simulation of transition radiation and electron identification for HERA-B ITEP-99-11. - Moscow : ITEP , 17 May 1999.

  17. Production with multi foils + saturation effect due to multi layer Absorption in foils w 10 keV Conversion X radiation d-electron MIP Pulse Height Threshold t=0 t=T M.L. Cerry et al., Phys. Rev. 10(1974)3594

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