2. South Pole Summer Wednesday Science Lectures January 22, 2003 8:00 PM Upper Galley Serap Tilav Bartol Research Institute University of Delaware SPASE: South Pole Air Shower Experiment What’s Cosmic Ray Air Showers got to do with growing Crystal Clear Ice at South Pole ?

3. What are Cosmic Rays? Naturally occurring particles (protons and nuclei) having very high energies From sources far outside the solar system Discovered nearly a century ago Studied with detectors on balloons and spacecraft as well as from the ground Positron, pion, kaon were all discovered by observations of cosmic-ray interactions in the atmosphere

4. Cosmic Ray spectrum Differential spectral index changes at ~ 3 x10 15 eV a = 2.7  a = 3.0 Continues to 3 x 10 18 eV Expect exp{-E / Z E max } cutoff for each Z

5. What is an electron volt? An electron volt, or eV for short, is a measure of energy. It is quite a small amount of energy similar to the amount of energy possessed by a single photon of light. RadiationEnergy Photon of light Can be detected by your eye 1 eV Ultra Violet ray from sun Enough to burn your skin 10 eV X-Ray Can pass right through your body 1000 eV = 1 keV Gamma rays detected by ground telescopes 10 12 eV = 1 TeV Cosmic Ray detected by the SPASE-2 experimentSPASE-2 10 15 eV = 1 PeV Cosmic Ray detected by the planned Pierre Auger ObservatoryPierre Auger Observatory 10 20 eV = 100 EeV Highest energy Cosmic Ray ever recorded 3x10 20 eV This is the amount of energy that you would feel if you dropped a bowling ball on your foot from a height of 1 metre! EnergyShorthand 10 3 eV = 1,000 eVKev = Kilo electron volt 10 6 eV = 1,000,000 eVMeV = Mega electron volt 10 9 eV = 1,000,000,000 eVGeV =Giga electron volt 10 12 eV = 1,000,000,000,000 eVTeV = Terra electron volt 10 15 eV = 1,000,000,000,000,000 eVPeV = Peta electron volt 10 18 eV = 1,000,000,000,000,000,000 eVEeV = Exa electron volt 10 21 eV = 1,000,000,000,000,000,000,000 eVZeV = Zeta electron volt

6. High-energy accelerators Accelerator labs  high energy particles Cosmic accelerators  cosmic rays –What are the sources? –How are the particles accelerated? –How do they get here? –What happens on the way?

7. Cosmic accelerators (some supernova remnants in our galaxy) SN1987A SN1054 Circa 1650 (Cas-A) SN1572

8. Really Big Cosmic accelerators: jets in active galaxies VLA image of Cygnus A 20 TeV gamma rays observed Higher energies obscured by IR light but the universe is transparent to but the universe is transparent to

9. Ground array samples shower front High altitudes desirable to be near the shower maximum 1- Low energy cosmic rays by satellites --direct detection of primary cosmic rays 2- Medium energy cosmic rays by balloons --direct detection of primary cosmic rays 3- High energy cosmic rays by Extensive Air Shower Arrays on ground --indirect detection of primary cosmic rays Detection Techniques of Cosmic Rays Top of atmosphere Ground Arrays Satellites Balloons 1 23

10. Primary Cosmic Ray Interaction with atmospheric nuclei Air Shower

11. Cosmic Ray Air Shower Array Detectors Scintillator detectorsWater Cherenkov detectors

12. SPASE-1 1988 – 1998 University of Leeds, Bartol Research Inst. Search for point sources of high energy (10 14 eV) gamma rays SPASE-1 Shack 1995 Inside the SPASE-1 Shack 1995 SPASE-1 array and the old Clean Air Bldg 1992SPASE-1 scintillator detector

13. South Pole Air Shower Experiment @ 10000ft altitude 30 stations on area of 16,000 sq. meters 4 modules per station each module contains hexagonal scintillator of 0.2 m 2 and a PMT 30m between stations Energy range of operation 10 13 eV to 10 16 eV

14. SPASE stations & signals cables

15. SPASE counting house SPASE electronics rack

16. Skiway SPASE SPASE/AMANDA Coincidence Experiment Electronic component of air showers detected by SPASE Primary CR direction and energy Penetrating muons detected by AMANDA Very good tool for Cosmic Ray mass composition & AMANDA calibration

17. 800 m 1000 m 1500 m 2000 m SPASE-2 AMANDA-A AMANDA-B 369m SPASE-1  = 12º  = 27º 885m Stereo View of AMANDA-B10 by SPASE-1 & SPASE-2 in 1997

18. Calibration of angular resolution SPASE-2 angular resolution:  63 ~1.5 o Inferred B10 resolution:  63 ~ 4.7 o for SPASE-1  63 ~ 5.2 o for SPASE-2 SPASE-2SPASE-1 Distribution of space angle between SPASE/AMANDA-B10

19. Absolute pointing ~ 1 o offset seen by SPASE-1, SPASE-2 & GASP Point source Monte Carlo also sees some offset (upper panel) SPASE-2

20. AMANDA-B10 seen from SPASE-2 AMANDA-B10 seen from SPASE-1 XXVII ICRC, 7-15 August 2001, Hamburg, Germany Poster Session HE2.01 Poster Board Number HE208 1997 AMANDA-B10 Survey with SPASE muons

21. Muon Tomography of South Pole Ice at AMANDA depths Dust layers located by SPASE/AMANDA coincident events

22. simulation K50 measures energy deposited by N  S30 measure particle density at 30m from the shower core

23. Cosmic Ray Composition around the Knee

25. 1400 m 2400 m AMANDA South Pole IceTop Skiway 4800 PMT Instrumented volume: 1 km3 (1Gt) 80 Strings IceCube is designed to detect neutrinos of all flavors at energies from 10 7 eV to 10 20 eV IceCube 1 station on top of each IceCube string 2 ice tanks per station 2 DOMs in each tank IceTop will detect Air Showers of energies 10 14 eV to 10 18 eV

26. IceTop Station 2 Ice Tanks per station 3.6 m 2 x 1 m each ~20 m IceCube Hole Two DOMs: 10 in PMTs High Gain w/station coincidence: 1 p.e. resolution Low Gain: 1  resolution

27. Tank2000 Tank2001 IceTop R&D

28. Tank2000 Tank2001 10 m SPASE2 Shack MAPO Where are the Tanks?

29. Technical details: Deployed in December 2000 Cylindrical Polyethylene tank radius=60cm height= 124cm Lined with white Tyvek inside for diffusive,high reflectance Black velvet on top 2 Standard AMANDA OMs frozen in top looking down Heating rod in the middle to channel excess water during freezing Filled with station water 36 days to freeze Block of ice of 1.14 m 2 x 0.99 m Tank2000 99.1 cm 51 cm 60 cm Heating rod (later removed) crack

30. Technical details: Deployed in December 2001 Cylindrical Polyethylene tank radius=107cm height= 124cm Lined with white Tyvek inside Black velvet on top 2 Standard AMANDA OMs frozen in top looking down PVC pipe in the middle with heating tapes, thermo sensors to channel excess water during freezing Several different color LEDs for later calibration Filled with station water 28 days to freeze Block of ice of 3.6 m 2 x 0.99 m Tank2001 99 cm 102 cm 107.32 cm Heating tapes Thermo sensors LEDs

31. Freezing Method Developed at Bartol Top-Down Freezing Insulated plastic barrel of d=10in h=16in Water pump circulates water through degasser 10 thermosensors monitor temperature Heater at output, Chiller at input Temps at input and output controlled via PC Water flow controlled Expansion water released from the pressure release' pipe

32. TopDown Method Tets in Lab

33. Commercial Methods for Making Crystal Clear Ice Method I Bottom-up freezing Metal container, metal tank Bottom at –30F Sides and top at ~30 ~34 F 51cm x 102cm x 38cm => 300lb blocks ~3.5 days freezing time Pump for water circulation Freon coils @ -30F Ambient temp ~ 30 ~ 34F Method II Bottom-up+ Sides-in Molds immersed in –10F water/alcohol bath water/alcohol bath circulated constantly Small pump on top of mold molding ice water –10F water/alcohol bath Pump for water circulation

35. Ice Occasions Ellsworth Wisconsin Moldings immersed in –10F turbo bath

36. Tests @ Port of Wilmington –DE Commercial freezer at ONLY 7F HOW to implement @ South Pole ?

37. Black painted Spole type outhouse Metal plate exposed to ~ -35F