ATIC, a Balloon Borne Calorimeter for Cosmic Ray Measurements

J. Isbert, G. Case, D. Granger, T.G. Guzik, B. Price, M. Stewart, J.P. Wefel.

Louisiana State University.

J.H. Adams, M. Christl. NASA/Marshall Space Flight Center.

H.S. Ahn, O. Ganel, K.C. Kim, S.A. Naqvi, E.S. Seo, R.

Sina, J.Z. Wang, J. Wu. University of Maryland.

A.R. Fazely, R. Gunasingha.

Southern University.

Y.J. Han, H.J. Kim, S.K. Kim. Seoul National University (Korea).

G. Bashindzhagyan, E. Kouznetsov, M. Panasyuk, A. Panov, G.

Samsonov, N. Sokolskaya, A. Voronin, V. Zatsepin. Moscow State University (Russia).

J. Chang, W.K.H. Schmidt.

Max Plank Institute (Germany).

Presented by: Joachim Isbert Session: Calorimeters in Astrophysics

Advanced Thin Ionization Calorimeter (ATIC)

Measurement Goals: Cosmic Ray Spectra of atomic nuclei from Hydrogen (Z=1) to Nickel (Z=28) in the Energy range from 10 GeV/A to 100 TeV/A Measurement Technique: Balloone borne Ionization Calorimeter. Location: Circumpolar flight from Mcmurdo, Antarctica. Launch: 12/28/00 04:25 UTC Termination: 01/13/01 03:56 UTC Recovery: 01/23/01; 01/25/01

ATIC Concept: Fully active thin calorimeter with low

Z interaction target. ATIC Detectors:

1) Silicon Matrix detector: Charge identification of CR particle. 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.

2) Scintillator hodoscopes: 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

3) Fully active BGO calorimeter: 8 layers; 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.

Assembly of the ATIC Payload

The ATIC Instrument Integration at McMurdo

ATIC is launched at 4:25 pm (local) on 12/28/00

Limits for Balloon borne Calorimeters: 1) Weight: Goal: Maximize Exposure AΩt for given weight ATIC Weight:

Flight 493N- Antarctica / 12-28-00

Balloon: W 29.47-2X-53 3701 lbs Science Gondola 3408 lbs Science Solar Array 64 lbs NSBF Electronics (SIP,etc.) 481 lbs NSBF Solar Array 140 lbs NASA Rotator 154 lbs 120 Ft. Parachute & susp. 486 lbs Ballast 161 lbs Misc. (1 Ballast Hopper,etc.) 41 lbs Gross Load 8636 lbs

2) Power: Stay within power limits of solar panels or

batteries. ATIC Power: Max Output of Solar Arrays: ~580 W ATIC Instrument uses:

Flight Data System: 148 W - Flight Control Unit, Hard Disk Drives, - Data Archive Unit, Power Control Unit, - Detector Control Unit, Auxiliary Science Stack, - Auxiliary Science Transmitter.

Detector Electronics: - Silicon Matrix, (Fem's, Aclb's, Bias Supply) 62 W - Plastic Scintillator, (Fem's, Aclb's, Bias Supply) 44 W - BGO Calorimeter, (Fem's, Aclb's, Bias Supply) 52 W Total Science Power: 306 W Thermal Control Heaters: 200 W (Not needed during 2000-01 flight) Total Power: 506 W Rechargeable Battery was used from launch until solar panels were able to supply full power.

3) Volume/ Shape: Transport, launch vehicle limit

4) Communication: Line of sight, satellite, over the horizon. All data were stored on board to data archive:

• Average rate during 2000-01 flight was ~3 GB / day or ~280 kilobits per second

Downlink telemetry: • Line-of-sight (LOS) downlink data stream < 333 kilobits/s • Over TDRSS housekeeping, rates, events < 4 kilobits/s • Status information over Argos via SIP < 29 bytes / 6 minutes

5) Termination and Recovery

ATIC was terminated on 1/13/2001

Recovery took place on 1/23/2001 and 1/25/2001

Data rates and All particle spectra for various thresholds:

0 2 4 6 8 10 12 14 160

500

1000

1500

2000

2500

3000Gated MT

Time (days)

Counts

-3 -2 -1 0 1 2 3 4 5 6

0

1

2

3

4

5

6

Total Energy Spectra

(Total Energy (GeV10log

(Number of Events)

10

log

ATIC Charge range data:

Charge0 0.5 1 1.5 2 2.5 30

5000

10000

15000

20000

25000

30000

35000

40000

45000

Nent = 1768148

Energy deposit > 10 Gev

Nent = 1768148

Charge3 4 5 6 7 8 9 100

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400Nent = 175703

Energy deposit > 10 Gev

Nent = 175703

ATIC Charge range data (2):

Charge10 12 14 16 18 20 22 24 26 28 30

0

200

400

600

800

1000

1200

1400

1600

Nent = 69888

Energy deposit > 10 Gev

Nent = 69888

ATIC is scheduled for a 2nd flight from Mcmurdo, Antarctica in December 2002/January 2003. An attempt will be made to circumnavigate Antarctica twice to gain the needed statistics for the science goals.