http://cosmicray.umd.edu/cream/images/stories/files/frontpage/seo.pdf

Cosmic-ray energetics and mass (CREAM) balloon project

The Cosmic Ray Energetics And Mass (CREAM) payload had its first successful flight in December 2004 from McMurdo Station, Antarctica as a Long Duration Balloon mission. Its aim is to explore the supernova acceleration limit of cosmic rays, the relativistic gas of protons, electrons and heavy nuclei arriving at Earth from outside of the solar system. The instrument is equipped with several systems to measure charge and energy spectra for Z = 1 – 26 nuclei over the energy range 10 11 – 10 15 eV . The Silicon Charge Detector (SCD) is a precision device to measure the charge of incident cosmic rays. The design, construction, integration and preliminary performance of the SCD are detailed in this paper.

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Silicon charge detector for the CREAM experiment

The Cosmic Ray Energetics And Mass (CREAM), a balloon-borne experiment, is under preparation for a flight in Antarctica at the end of 2004. CREAM is planned to measure the energy spectrum and composition of cosmic rays directly at energies between 1 TeV and 1000 TeV. Incident particle energies will be measured by a transition radiation detector and a sampling calorimeter. The calorimeter was constructed at the University of Maryland and tested at CERN in 2003. Performance of the calorimeter during the beam tests is reported.

Performance of CREAM Calorimeter: Results of Beam Tests

The Cosmic Ray Energetics And Mass (CREAM) experiment is designed to measure cosmic ray elemental spectra to help understand the source and acceleration mechanisms of ultra-high-energy cosmic rays. The payload is planned to launch in December 2004 from McMurdo Station, Antarctica as a balloon mission. A Silicon Charge Detector (SCD) was designed and constructed for the CREAM experiment to provide precision charge measurements of incident cosmic rays with a resolution of 0.2 charge unit or better. The SCD was exposed to heavy ion beams at CERN's H2 beam line in November 2003. The results reported here show the SCD performs as designed.

Heavy ion beam test results of the silicon charge detector for the CREAM cosmic ray balloon mission

The balloon-borne cosmic-ray experiment CREAM (Cosmic Ray Energetics And Mass) has completed two flights in Antarctica, with a combined duration of 70 days. One of the detectors in the payload is the SCD (silicon charge detector) that measures the charge of high energy cosmic rays. The SCD was assembled with silicon sensors. A sensor is a 4 × 4 array of DC-coupled PIN diode pixels with the total active area of 21 × 16 mm2. The SCD used during the first flight (December 2004-January 2005) was a single layer device, then upgraded to a dual layer device for the second flight (December 2005-January 2006), covering the total sensitive area of 779 × 795 mm2. Flight data demonstrated that adding a second layer improved SCD performance, showing excellent particle charge resolution. With a total dissipation of 136 W for the dual layer system, special care was needed in designing thermal paths to keep the detector temperature within its operational range. As a consequence, flight temperatures of the SCD, even at diurnal maximum were kept below 38°C. The SCD mechanical structure was designed to minimize the possibility of damage to the sensors and electronics from the impacts of parachute deployment and landing. The detector was recovered successfully following the flight and is being refurbished for the next flight in 2007. Details of construction, operation, and performance are presented for the dual-layered SCD flown for the second CREAM flight.

S. Beach

Papers

Cosmic-ray energetics and mass (CREAM) balloon experiment

Cosmic Ray Energetics And Mass : Expected Performance

Cosmic ray energetics and mass: configuration and progress on construction and testing