LSU 01/12/05 Project Initiation Confer ence 01/13/05 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 14 – 30 days over the continent of Antarctica, will measure the charge composition and energy spectra of primary cosmic rays over the energy range from about 10 10 to 10 14 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 for Solar System Research
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The Advanced Thin Ionization Calorimeter (ATIC) Long Duration Balloon Experiment
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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 14
– 30 days over the continent of Antarctica, will measure the charge composition and energy spectra of primary cosmic rays over the energy range
from about 1010 to 1014 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 for Solar System Research
ATIC Program Summary Investigate relationship between Supernova
Remnant (SNR) Shocks and high energy galactic cosmic rays (GCR)
Are SNR the “cosmic accelerators” for GCR
Measure GCR Hydrogen to Nickel from 50 GeV to ~100 TeV total energy
Determine spectral differences between elements
Flight test pixilated Silicon detector
Multiple flights needed to obtain necessary exposure ATIC-1 test flight during 2000-2001 ATIC-2 during 2002-2003 – 17 days exposure ATIC-3 anticipated for 2005
Scientific Ballooning programs at Universities provides unique education experiences for the future aerospace workforce ATIC involved over 45 LSU & SU students
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 (400 BGO crystals
for ATIC-3) to foster and measure the nuclear - electromagnetic cascade showers Geometrical factor: 0.24 m2sr (S1 – S3 – BGO6)
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 very similar 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, including a constant residual pathlength (0.13 g/cm2), is needed.
Preliminary charge histograms for E > 50 GeV from the ATIC-2 flight
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 statusCommand Capability: Power on / off; Trigger type; Thresholds; Pre-scaler; Housekeeping frequency; LOS data rate, Reboot nodes; High Volt settings; Data collection on / offGeometry Factors: S1-S3: 0.42 m2sr; S1-S3-BGO 6: 0.24 m2sr; S1-S3-BGO 8: 0.21 m2sr
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: 20 – 30 C Altitude: 37 1.5 km
Launch: 12/28/00 04:25 UTC Begin Science: 12/29/00 03:54
First ATIC Science Flight from McMurdo 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 1st 10 days then held constant Internal Temperature: 12 – 22 C Altitude: 36.5 1.5 km
Launch: 12/29/02 04:59 UTC Begin Science: 12/30/02 05:40
Preparation for ATIC-3 Refurbish detectors Fall 2003 – Spring 2004 Reconstruct missing structure (left on ice) Spring 2004 Procure missing carbon target (left on ice) Spring 2004 Reconstruct pressure vessel ring / flanges March – June 2004 Leak & Proof pressure test vessel July 2004
Assigned extra task by NASA to certify ATIC for 2004 July 17, 2004
Arrive NSBF for Pre-deployment Integration August 19, 2004
Complete Pre-deployment Integration Hang-Test September 16, 2004
Receive stand-down for 2004 season from NASA October 20, 2004 Directed to maintain ATIC in near flight ready status Extra effort remains unreimbursed by NASA
Packed and ready to ship on 5 days notice Instrument powered in shipping container for running preventative maintenance
Obtained weight for fully assembled payload Verified structural analysis for ATIC-3 configuration Following test, disassembled payload and packed for shipment to McMurdo
Assembled & tested instrument in ATIC-3 flight configuration Added two layers to calorimeter
Flight configuration software loaded and tested
Integrated with NSBF SIP VHF, TDRSS, Iridium All uplink & downlink channels tested
Ground system assembled & tested Through ROCC to flightline control Though POCC to flightline & LSU
control Integrated & tested all NSBF equipment
Pointing rotator NSBF solar arrays Flight ladder, UTP
ATIC Mechanical Certification Initial ATIC Mechanical Report July 2000 ATIC structure certified by NSBF August 2000 Thermal analysis reviewed and approved August 2000 Approval to fly Kevlar vessel at 8 psi November 2000 Successful test flight (ATIC-1) Dec 2000 to Jan 2001
Pressure Vessel Test (10 psi for 24 hrs.) May 2002 Mechanical Report Update July 2002 ATIC structure certified by NSBF August 2002 Thermal analysis reviewed and approved August 2002 Successful science flight (ATIC-2) Dec 2002 to Jan 2003
Pressure Vessel Test (10 psi for 24 hrs.) July 2004 Verified that original FEA was for 10 layer calorimeter July 2004 Mechanical Report Update August 2004 ATIC structure certified by NSBF September 2004
10 discrete lines for power on/off control 4 discrete lines for pressure control Used only at launch, termination, and emergencies
Serial Commands Simple protocol - Uplink cmd, downlink cmd ACK, execute cmd, downlink cmd status/return All primitive cmds are 10 bytes long, so are encoded twice in each 20 byte cmd packet for error
checking Almost all uplinked cmds will be two bytes long and will execute a script of primitive cmds. Command types
Software - Reboot node, Restart process, Start/stop LOS XMTR, etc. Power - Power on/off subsystem, etc. Detector - Calibrate BGO, Select trigger, etc.
Uplink Commands: LOS for experiment check-out max of 100 cmds / hr All primitive cmds are 10 bytes long, so are encoded twice in each 20 byte cmd packet for error
checking During normal ops max of 4 two byte cmds / hr Problem diagnosis & resolution during LDB flight.
Require cmd rate > 4 cmds/hr May require LOS link via airplane underflight
To meet science goals ATIC needs > 10 good H events at energies > 100 TeV Minimum TOTAL exposure > 40 days with altitude above 110,000 feet Implies multiple flights over multiple years
Minimum Success per Flight: About 8 days with altitude above 110,000 feet with stability of 10,000 feet Integrity of Aux Sci XTM data at 80% while in range 90% of Silicon Matrix area, S1, S3 and BGO layers 2 through 8 are operational Recovery of data from flight recorders Recovery of all critical payload components Photographs to assess structural damage
Desired Performance per Flight: 14 days with altitude above 124,000 feet and stability of 5,000 feet All detectors fully operational Recovery of all data and entire payload
Two (or more) circumnavigations (~30 days) is HIGHLY desired Reduce need for fourth flight Now have two payloads as precedent (TIGER, CREAM)
~1000 square feet experiment setup and work area 20 feet linear bench/table space for detector work 20 feet linear bench/table/desk space for computers 6 chairs 3 ton overhead hoist with 20 feet clearance
Power: One 220 V, 3 phase, 60 Hz, 6 Amp nominal Two 120 V, single phase, 60 Hz, 15 Amp on UPS Two 120 V, single phase, 60 Hz, 15 Amp
Gas: 3 cylinders of dry Nitrogen System to transfer gas to flight cylinders Clean, dry, compressed air
Communication: Telephone, Internet connection
Other: Access to machine shop Dedicated van for crew transport
Electrical generator to power ATIC up to launch Command & Data Interface:
Interface to ATIC Ground Data System at McMurdo Interface to ATIC internet repeater at Palestine
Telemetry: Line of sight used during experiment check-out tuning
Downlink 333 kbits/s via Aux. Sci. Transmitter Uplink max of 100 cmds / hour
TDRSS and/or VHF for status & data Max of 4 two byte cmds / hour
Flight Operations: 24 x 7 monitoring of payload at ROCC and POCC Underflight for emergency payload control (if needed)
Termination & Recovery: Air support for termination, follow-down and chute cutaway Air support for recovery of flight data disks and all critical payload
Telemetry: Auxiliary science transmitter to downlink much of the ATIC data stream
during LOS (333 kilobits/s, bi-phase encoded) Will use TDRSS, VHF & Iridium High Gain TDRSS is HIGHLY desired
100 kbps would allow majority of data to be downlinked Reduce need for full recovery
Commanding: Discrete commands through Auxiliary Science Stack (about 14 cmds) From ground through SIP to experiment From underflight through SIP to experiment From experiment to SIP (GPS position, altitude)