The Advanced Thin Ionization Calorimeter (ATIC) Long Duration Balloon Experiment

Transcription

1 The Advanced Thin Ionization Calorimeter (ATIC) Long Duration Balloon Experiment A ~1,660 kg experiment, carried to the near-space environment (~36 km) by a large volume (sufficient to fill a football stadium) helium filled balloon for days over the continent of Antarctica, will measure the charge composition and energy spectra of primary cosmic rays over the energy range from about to ev in order to investigate the relationship between high energy galactic matter and remnant supernova shock waves. Louisiana State University, Marshall Space Flight Center, University of Maryland, Southern University, Moscow State University, Max Plank Institute - Lindau LSU 10/12/05 ATIC Public Summary 1

2 The ATIC Collaboration J.H. Adams 2, H.S. Ahn 3, G.L. Bashindzhagyan 4, K.E. Batkov 4, J. Chang 6,7, M. Christl 2, A.R. Fazely 5, O. Ganel 3 R.M. Gunasingha 5, T.G. Guzik 1, J. Isbert 1, K.C. Kim 3, E.N. Kouznetsov 4, M.I. Panasyuk 4, A.D. Panov 4, W.K.H. Schmidt 6, E.S. Seo 3, N.V. Sokolskaya 4, J.Z. Wang 3, J.P. Wefel 1, J. Wu 3, V.I. Zatsepin 4 1. Louisiana State University, Baton Rouge, LA, USA 2. Marshall Space Flight Center, Huntsville, AL, USA 3. University of Maryland, College Park, MD, USA 4. Skobeltsyn Institute of Nuclear Physics, Moscow State University, Russia 5. Southern University, Baton Rouge, LA, USA 6. Max Plank Institute fur Aeronomie, Lindau,Germany 7. Purple Mountain Observatory, Chinese Academy of Sciences (CAS), China LSU 10/12/05 ATIC Public Summary 2

3 Cosmic Rays extend over a large energy range LSU 10/12/05 ATIC Public Summary 3

4 Standard Model of Cosmic Ray Acceleration Supernova shock waves may accelerate cosmic rays via first order Fermi process Model predicts an upper energy limit of E ~ Z x ev ATIC Energy Range LSU 10/12/05 ATIC Public Summary 4

5 ATIC Program Summary Investigate relationship between Supernova Remnant (SNR) Shocks and high energy galactic cosmic rays (GCR) Multiple flights needed to obtain necessary exposure ATIC-1 test flight during ATIC-2 during days exposure ATIC-3 scheduled for 2005 Scientific Ballooning programs at Universities provides unique education experiences for the future aerospace workforce ATIC involved over 45 LSU & SU students Are SNR the cosmic accelerators for GCR Measure GCR Hydrogen to Nickel from 50 GeV to ~100 TeV total energy Determine spectral differences Study High Energy Electron Spectrum Flight test pixilated Silicon detector LSU 10/12/05 ATIC Public Summary 5

6 ATIC Instrument Summary Ionization Calorimetry only practical method to measure high energy light elements Silicon Matrix has 4,480 pixels to measure GCR charge in presence of shower backscatter Plastic scintillator hodoscope, embedded in Carbon target, provides event trigger plus charge & trajectory information Fully active calorimeter includes 320 Bismuth Germinate (BGO) crystals to foster and measure the nuclear - electromagnetic cascade showers Geometrical factor: 0.24 m 2 sr (S1 S3 BGO6) LSU 10/12/05 ATIC Public Summary 6

7 ATIC Instrument Details Si-Matrix: 4480 pixels each 2 cm x 1.5 cm mounted on offset ladders; 0.95 m x 1.05 m area; 16 bit ADC; CR-1 ASIC s; sparsified readout. Scintillators: 3 x-y layers; 2 cm x 1 cm cross section; Bicron BC-408; Hamamatsu R5611 pmts both ends; two gain ranges; ACE ASIC. S1 336 channels; S2 280 channels; S3 192 channels; First level trigger: S1-S3 Calorimeter: 8 layers (10 for ATIC-3); 2.5 cm x 2.5 cm x 25 cm BGO crystals, 40 per layer, each crystal viewed by R5611 pmt; three gain ranges; ACE ASIC; 960 channels (1200 for ATIC-3). Data System: All data recorded on-board; 70 Gbyte disk (150 Gbyte for ATIC-3); LOS data rate 330 kbps; TDRSS data rate 4 kbps (6+ kbps for ATIC-3); Underflight capability (not used). Housekeeping: Temperature, Pressure, Voltage, Current, Rates, Software Status, Disk status Command Capability: Power on / off; Trigger type; Thresholds; Pre-scaler; Housekeeping frequency; LOS data rate, Reboot nodes; High Volt settings; Data collection on / off Geometry Factors: S1-S3: 0.42 m 2 sr; S1-S3-BGO 6: 0.24 m 2 sr; S1-S3-BGO 8: 0.21 m 2 sr LSU 10/12/05 ATIC Public Summary 7

8 Profile of 8 TeV total energy event in ATIC LSU 10/12/05 ATIC Public Summary 8

9 There are three major US bases in Antarctica LSU 10/12/05 ATIC Public Summary 9

10 Satellite view on a good day LSU 10/12/05 ATIC Public Summary 10

11 High altitude winds are circumpolar during summer LSU 10/12/05 ATIC Public Summary 11

12 Start with a 40 hours trip & having a day vanish LSU 10/12/05 ATIC Public Summary 12

13 Spring time in Christchurch was enjoyable LSU 10/12/05 ATIC Public Summary 13

14 Would we follow in the footsteps of Scott? LSU 10/12/05 ATIC Public Summary 14

15 The US Antarctica Program supplied us well LSU 10/12/05 ATIC Public Summary 15

16 The C-141 flight to McMurdo took about 6 hours LSU 10/12/05 ATIC Public Summary 16

17 Arrived to find Ivan the Terra Bus waiting LSU 10/12/05 ATIC Public Summary 17

18 There were spectacular views.. of ice! LSU 10/12/05 ATIC Public Summary 18

19 McMurdo is the largest base in Antarctica LSU 10/12/05 ATIC Public Summary 19

20 Scott occupied site in 1902, but the station was not built until 1956 LSU 10/12/05 ATIC Public Summary 20

21 The early explorers were a hardy crew LSU 10/12/05 ATIC Public Summary 21

22 Happy Camper School was required for all new comers LSU 10/12/05 ATIC Public Summary 22

23 The LDB base was located at Williams Field on the Ross Ice Shelf about 8 miles from McMurdo LSU 10/12/05 ATIC Public Summary 23

24 We had almost all the comforts of home LSU 10/12/05 ATIC Public Summary 24

25 The P.I.G barn provided a good work environment LSU 10/12/05 ATIC Public Summary 25

26 Assembly of ATIC at Willy Attach the upper support structure Assemble / test detector stack and mount in lower support structure Install Kelar pressure vessel shells Solar arrays provide power & the payload is rolled out the hanger door Attach the thermal protection ATIC is transported to the insulation launch pad LSU 10/12/05 ATIC Public Summary 26

27 Holidays and weekends we had a chance to relax LSU 10/12/05 ATIC Public Summary 27

28 Louisiana fried turkey was a popular treat LSU 10/12/05 ATIC Public Summary 28

29 Satellite view on a not so good day LSU 10/12/05 ATIC Public Summary 29

30 When the going got tough, the tough got going (to McMurdo) LSU 10/12/05 ATIC Public Summary 30

31 Every once in a while a visitor came to call LSU 10/12/05 ATIC Public Summary 31

32 Finally everything was ready for launch LSU 10/12/05 ATIC Public Summary 32

33 ATIC Test Flight from McMurdo 43.5 Gbytes Recorded Data 26,100,000 Cosmic Ray triggers 1,300,000 Calibration records 742,000 Housekeeping records 18,300 Rate records Low Energy Trigger > 10 GeV for protons >70% Live-time >90% of channels operating nominally Internal pressure (~8 psi) held constant Internal Temperature: C Altitude: 37 ± 1.5 km Launch: 12/28/00 04:25 UTC Begin Science: 12/29/00 03:54 UTC End Science: 01/12/01 20:33 UTC Termination: 01/13/01 03:56 UTC Recovery: 01/23/01; 01/25/01 LSU 10/12/05 ATIC Public Summary 33

34 First ATIC Science Flight from McMurdo Launch: 12/29/02 04:59 UTC Begin Science: 12/30/02 05:40 UTC End Science: 01/18/03 01:32 UTC Termination: 01/18/03 02:01 UTC Recovery: 01/28/03; 01/30/03 65 Gbytes Recorded Data 16,900,000 Cosmic Ray triggers 1,600,000 Calibration records 184,000 Housekeeping records 26,000 Rate records High Energy Trigger > 75 GeV for protons >96% Live-time >90% of channels operating nominally Internal pressure (~8 psi) decreased slightly (~0.7 psi) for 1 st 10 days then held constant Internal Temperature: C Altitude: 36.5 ± 1.5 km LSU 10/12/05 ATIC Public Summary 34

35 Flight and Recovery Flight path for ATIC-1 (2000) and ATIC-2 (2002) The good ATIC-1 landing on 1/13/01 (left) and the not so good landing of ATIC-2 on 1/18/03 (right) ATIC is designed to be disassembled in the field and recovered with Twin Otters. Two recovery flights are necessary to return all the ATIC components. Pictures show 1 st recovery flight of ATIC-1 LSU 10/12/05 ATIC Public Summary 35

36 Preliminary Results Summary Preliminary results from ATIC-1 and ATIC-2 Fill gap between low energy AMS and high energy JACEE with accurate measurements Preliminary indication that Hydrogen and Helium spectral indices are different Measurements of Iron group show flattening of spectrum Have measured GCR electrons up to about 2 TeV At the highest energies, the heavy ion spectra show deviations, which might suggest that a modified Leaky Box Model is needed. C O Ne Mg Si S S Ca Fe Preliminary charge histograms for E > 50 GeV from the ATIC-2 flight LSU 10/12/05 ATIC Public Summary 36

37 An example of event reconstruction Primary (He) Albedo x, cm z, cm y, cm y, cm z, cm x, cm LSU 10/12/05 ATIC Public Summary 37

38 Charge resolution in the p-he group EBGO > 50 GeV EBGO > 500 GeV EBGO > 5 TeV LSU 10/12/05 ATIC Public Summary 38

39 Preliminary ATIC-2 Energy spectra for H and He Proton (top) and Helium (bottom) Energy Deposit spectra from the ATIC-2 flight used as the input to the first order de-convolution calculation. De-convolved Proton and Helium spectrum compared with other measurements and propagation calculations using the Leaky Box model (1, 3) and a diffusion model with weak reacceleration (2, 4). LSU 10/12/05 ATIC Public Summary 39

40 Charge resolution in the CNO-group EBGO > 50 GeV EBGO > 250 GeV EBGO > 1 TeV C O LSU 10/12/05 ATIC Public Summary 40

41 Charge resolution in the Ne-Si group EBGO > 50 GeV EBGO > 250 GeV EBGO > 1 TeV Ne Mg Si S LSU 10/12/05 ATIC Public Summary 41

42 Charge resolution in the Fe group EBGO > 50 GeV EBGO > 250 GeV EBGO > 1 TeV Fe S Ca LSU 10/12/05 ATIC Public Summary 42

43 Energy spectra of abundant nuclei C C O/10 Mg Mg O Si Si/10 Ne/100 Ne Fe Fe/100 HEAO-3-C2 ATIC-2 CRN LSU 10/12/05 ATIC Public Summary 43

44 Leaky Box Cosmic Ray Transport LSU 10/12/05 ATIC Public Summary 44

45 Energy spectra of abundant nuclei C Mg O/10 Si/10 Fe/100 Ne/100 HEAO-3-C2 ATIC-2 CRN LSU 10/12/05 ATIC Public Summary 45

46 ATIC also is able to identify CR electrons High energy electrons provides addition information about the GCR source Possible bump at GeV seen by both Kobayashi and ATIC may be a source signature? e LSU 10/12/05 ATIC Public Summary 46

47 Anticipated ATIC Schedule July 25, 05 August 05 ~October 1, 05 October 31, 05 November 05 November 4, 05 ~November 27, 05 ~December 1, 05 ~December 5, 05 ~December 15, 05 ~December 21, 05 ~January 18, 06 ~February 3, 06 Instrument packing complete Ship ATIC to McMurdo Late shipment (3 small crates planned) Setup crew arrives on flight line Payload setup and testing Silicon Matrix crew arrives Partial crew change out Calibrations / Testing with muons Flight Ready Balloon flight launch Partial crew change out Balloon flight termination Instrument recovered, packed for shipment and remaining crew leaves LSU 10/12/05 ATIC Public Summary 47

48 Flight Operations Schedule LSU 10/12/05 ATIC Public Summary 48

49 Our enthusiastic crew is looking forward to another successful ATIC flight! LSU 10/12/05 ATIC Public Summary 49