1. June 1, 2005Tom Gaisser CORSIKA summer school Cosmic-ray cascades in the atmosphere 1)Air shower phenomenology 2)Inclusive fluxes in the atmosphere

2. June 1, 2005Tom Gaisser CORSIKA summer school 1) Air showers Generalities Current questions –Composition around the knee –Transition to extra-galactic cosmic rays? –Energetics of extra-galactic component Example of IceTop/IceCube

3. June 1, 2005Tom Gaisser CORSIKA summer school Cascades in the atmosphere

4. June 1, 2005Tom Gaisser CORSIKA summer school Boundary conditions & scaling Air shower, primary of mass A, energy E 0 : –N(X=0) = A  (E- E 0 /A) for nucleons –N(X=0) = 0 for all other particles Uncorrelated flux from power-law spectrum: –N(X=0) =  p (E) = K E -(  +1) – ~ 1.7 E -2.7 ( cm -2 s -1 sr -1 GeV -1 ), top of atmosphere F ji ( E i,E j ) has no explicit dimension, F  F(  ) –  = E i /E j & ∫…F(E i,E j ) dE j / E i  ∫…F(  ) d  /  2 – Small scaling violations from m i,  QCD ~ GeV

5. June 1, 2005Tom Gaisser CORSIKA summer school The atmosphere The atmosphere (exponential approximation) Pressure = X v = X o exp{ -h v / h o }, where h o = 6.4 km for X v < 200 g / cm 2 Density =  = -dX v / dh v = X v / h o and X 0 = 1030 g / cm 2

6. June 1, 2005Tom Gaisser CORSIKA summer school Cascade equation for  +/-

7. June 1, 2005Tom Gaisser CORSIKA summer school Interaction vs. decay X v = 100 g / cm 2 at 15 km altitude which is comparable to interaction lengths of hadrons in air Relative magnitude of i and d i = X cos  ( E /  i ) determines competition between interaction and decay

8. June 1, 2005Tom Gaisser CORSIKA summer school Heitler’s pedagogical toy model of multiplicative cascades

9. June 1, 2005Tom Gaisser CORSIKA summer school  +/-   +

10. June 1, 2005Tom Gaisser CORSIKA summer school Lateral distributions Modified NKG formula (Akeno) for hadronic cascades Greisen’s empical form for lateral distribution of low-energy ( few GeV) muons in EAS  +/- e +/-

11. June 1, 2005Tom Gaisser CORSIKA summer school Super-simple simulations -- a useful guide for setting real simulations? Use longitudinal development formula with starting point fluctuations. : Use NKG, Greisen lateral distributions Map out response functions –Primary energy –Space and angular distributions Example later (IceTop)

12. June 1, 2005Tom Gaisser CORSIKA summer school Spectrometers (  A = 1 resolution, good E resolution) Calorimeters (less good resolution) Primary spectrum Air showers Air-shower arrays on the ground to overcome low flux. Don’t see primaries directly. Current questions

13. June 1, 2005Tom Gaisser CORSIKA summer school Aspen, April 26-30

14. June 1, 2005Tom Gaisser CORSIKA summer school 30 Rigidity-dependence Acceleration, propagation – depend on B: r gyro = R/B –Rigidity, R = E/Ze –E c (Z) ~ Z R c r SNR ~ parsec –  E max ~ Z * 10 15 eV – 1 < Z < 30 (p to Fe) Slope change should occur within factor of 30 in energy With characteristic pattern of increasing A Problem: continuation of smooth spectrum to EeV

15. June 1, 2005Tom Gaisser CORSIKA summer school B. Peters on the knee and ankle B. Peters, Nuovo Cimento 22 (1961) 800 Peters cycle: systematic increase of Peters cycle: systematic increase of approaching E max approaching E max should begin to decrease again should begin to decrease again for E > 30 x E knee for E > 30 x E knee

16. June 1, 2005Tom Gaisser CORSIKA summer school Recent KASCADE data show increasing fraction of heavy nuclei with expected cutoff sequence starting at ~3 PeV M. Roth et al., Proc ICRC 2003 (Tsukuba) vol 1, p 139 Based on N  /Ne analysis (KASCADE talks on Saturday) KASCADE Grande to extend to > 10 17 eV 10 15 10 16 10 17

17. June 1, 2005Tom Gaisser CORSIKA summer school piering Three new kilometer-scale detectors

18. June 1, 2005Tom Gaisser CORSIKA summer school Hi-Res stereo fluorescence detector in Utah Air shower detectors AGASA (Akeno, Japan) 100 km 2 ground array Sketch of ground array with fluorescence detector – Auger Project realizes this concept

19. June 1, 2005Tom Gaisser CORSIKA summer school Measuring the energy of UHECR Ground array samples shower front –Well-defined acceptance –Simulation relates observed ground parameter to energy –  / e for composition Fluorescence technique tracks shower profile –Track-length integral gives calorimetric measure of energy: E ~  ∫ N(X) dX –X max sensitive to primary mass: X max ~  ln(E 0 /A)

20. June 1, 2005Tom Gaisser CORSIKA summer school HR2 Profile Plot (from Doug Bergman’s HiRes talk at Aspen, Jan 2002) Top plot shows observed NPE (points) together with predicted NPE from final GH fit: green- fluorescence, blue- Cerenkov, red-total Bottom plot shows shower size initially (blue) and after Cerenkov correction (black) along with GH fit Note: need to correct for lost energy (, high energy  and e-m shower into the ground)

21. June 1, 2005Tom Gaisser CORSIKA summer school AGASA 2 x 10 20 eV event N. Hayashida et al., PRL 73 (1994) 3491  All charged particles

22. June 1, 2005Tom Gaisser CORSIKA summer school Biggest event Comparison to –Proton showers –Iron showers –  showers Horizontal EAS –only muons survive –Haverah Park:  /p 10 19 eV –AGASA: similar limit Limit on  showers constrains TD models Fly’s Eye, Ap. J. 441 (1995) 295

23. June 1, 2005Tom Gaisser CORSIKA summer school Xmax vs Energy Protons penetrate deeper into atmosphere Heavy nuclei develop higher up Plot shows a summary of data over 5 decades Several techniques

24. June 1, 2005Tom Gaisser CORSIKA summer school Where is transition to extragalactic CR? G. Archbold, P. Sokolsky, et al., Proc. 28 th ICRC, Tsukuba, 2003 HiRes new composition result: transition occurs before ankle Original Fly’s Eye (1993): transition coincides with ankle 3 EeV 0.3 EeV

25. June 1, 2005Tom Gaisser CORSIKA summer school Energy content of extra-galactic component depends on location of transition Composition signature: transition back to protons Uncertainties: Normalization point: 10 18 to 10 19.5 used Factor 10 / decade Spectral slope  =2.3 for rel. shock =2.0 non-rel. E min ~ m p (  shock ) 2

26. June 1, 2005Tom Gaisser CORSIKA summer school Power needed for extragalactic cosmic rays assuming transition at 10 19 eV Energy density in UHECR,  CR ~ 2 x 10  erg/cm 3 –Such an estimate requires extrapolation of UHECR to low energy –  CR = (4  /c)  E  (E) dE = (4  /c){E 2  (E)}  E=10 19 eV x ln{E max /E min } –This gives  CR ~ 2 x 10  erg/cm 3 for differential index  = 2,  (E) ~ E -2 Power required ~  CR /10 10 yr ~ 1.3 x 10 37 erg/Mpc 3 /s –Estimates depend on cosmology and extragalactic magnetic fields: –3 x 10 -3 galaxies/Mpc 3 5 x 10 39 erg/s/Galaxy –3 x 10 -6 clusters/Mpc 3 4 x 10 42 erg/s/Galaxy Cluster –10 -7 AGN/Mpc 3 10 44 erg/s/AGN –~1000 GRB/yr 3 x 10 52 erg/GRB

27. June 1, 2005Tom Gaisser CORSIKA summer school IceCube with IceTop after 04/05 deployment season 4 IceTop Stations deployed in December 2004 1st IceCube string deployed on Jan 29 2005

28. June 1, 2005Tom Gaisser CORSIKA summer school IceTop Calibration – pointing –  – E deposition Tag background –Reconstruction –rejection Cosmic-rays –3 x 10 14 – 10 18 eV –‘knee’ to ‘ankle’ = galactic to extragalactic?

29. June 1, 2005Tom Gaisser CORSIKA summer school IceTop station Two Ice Tanks 2.7 m 2 x 0.9 m deep (scaled-down version of Haverah, Auger) Integrated with IceCube: same hardware, software Coincidence between tanks = potential air shower Local coincidence with no hit at neighboring station tags muon in deep detector Signal in single tank = potential muon Significant area for horizontal muons Low Gain/High Gain operation to achieve dynamic range Two DOMs/tank gives redundancy against failure of any single DOM because only 1 low-gain detector is needed per station ~ 5-10 TeV

30. June 1, 2005Tom Gaisser CORSIKA summer school Run 872 Event 5945

31. June 1, 2005Tom Gaisser CORSIKA summer school Simulations of R Engel (Aspen) comparing KASCADE-Grande with IceCube/IceTop

32. June 1, 2005Tom Gaisser CORSIKA summer school IceTop and SPASE 2

33. June 1, 2005Tom Gaisser CORSIKA summer school IceTop SPASE Coincidence Coincidence within +/- 200  sec signal and flat background Coincidence within +/- 3  sec - 1.4  sec offset IceTop/SPASE coincidence rate 0.06 Hz

34. June 1, 2005Tom Gaisser CORSIKA summer school Simulated response of single station hits (mostly single muons in deep ice) Low coincidence rate is due to 4-string geometry,  < 6 o in ‘05

35. June 1, 2005Tom Gaisser CORSIKA summer school Core location distributions, E p =18 TeV

36. June 1, 2005Tom Gaisser CORSIKA summer school Core locations for E p = 2.7 PeV Note that ring of distant singles from PeV showers will be removed by surrounding stations in larger array

37. June 1, 2005Tom Gaisser CORSIKA summer school E p, cos(  ) distributions of 4- folds 3-fold rate ~ 0.30 Hz

38. June 1, 2005Tom Gaisser CORSIKA summer school 0o0o 90 o Azimuthal distributions

39. June 1, 2005Tom Gaisser CORSIKA summer school Spectrum of deposited energy for 4-fold events (VEM*factor)

40. June 1, 2005Tom Gaisser CORSIKA summer school Measured rate: f3 + f4 = 0.73 Hz Comparison of simulated vs measured rates Coincidence rate with string 21 trigger ~.07 Hz

41. June 1, 2005Tom Gaisser CORSIKA summer school IceTop daily monitoring page http://icecube.bartol.udel.edu IceTop trigger: > 10 DOMs > threshold in 2  s Hard local coincidence between DOMs in adjacent tanks

42. June 1, 2005Tom Gaisser CORSIKA summer school Angular distributions IceTop TriggersIn-Ice Triggers

43. June 1, 2005Tom Gaisser CORSIKA summer school Event 79 IceTop display (ATWD ch 1) 0.8 v 100200 ns Voltage vs time (20 ns per division) High-gain DOMs Low-gain DOMs 39 30 29 21

44. June 1, 2005Tom Gaisser CORSIKA summer school Compress by ~10 for IceTop Goal: express wave-forms in units of VEM (Vertical Equivalent Muon ) as in Auger

45. June 1, 2005Tom Gaisser CORSIKA summer school Wave forms IceTop Spacing 125 m Width ~ 100 ns Auger: Spacing 1500 m Widths ~ 1  sec

46. June 1, 2005Tom Gaisser CORSIKA summer school Expected signals in 2006 Single station rate ~ 120 Hz –~ 1.5 Hz coincident rate for calibration Cosmic-ray showers 3.10 14 -10 17 eV –Total rate of > 4-fold EAS: ~ 4 Hz –~100 / day > 10 16 eV (~50  @ 2 km) –~ 1 / day > 10 17 eV (~300  @ 2 km) – ~ 10% of IceTop triggers give coincidences with deep array

47. June 1, 2005Tom Gaisser CORSIKA summer school DOMs in IceTop

48. June 1, 2005Tom Gaisser CORSIKA summer school Fill tanks Most tanks to be filled with water from drill system --How to filter and remove contaminants is TBD

49. June 1, 2005Tom Gaisser CORSIKA summer school Steffen-CRW_0361 19-jan-05 Daan Hubert 8-dec-04? JohnKelley 02-jan-05 Station 39

50. June 1, 2005Tom Gaisser CORSIKA summer school John Kelley P105005 06-jan-05 John Kelley P105008 06-jan-05 Steffen CRW_0332 19-jan-05 Steffen CRW_0344 19-jan-05 Station 29, TANK 102 (only tank with bubbles)

51. June 1, 2005Tom Gaisser CORSIKA summer school Insulate & darken tanks

52. June 1, 2005Tom Gaisser CORSIKA summer school IceCube string anchored between IceTop tanks

53. June 1, 2005Tom Gaisser CORSIKA summer school IceTop Detector 2 m 0.9 m Diffusely reflecting liner Simulations of tank response as well as air showers are needed!