ISS-CREAM Flight Operation

International audienceThe Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) is designed and built to measure the elemental energy spectra of cosmic-ray particles (1 ≤ Z ≤ 26) and electrons. It measures the energy of incident cosmic rays from 10^12 to 10^15 eV. ISS-CREAM was launched and deployed to the ISS in August 2017. The Science Operations Center (SOC) at the University of Maryland has been operating the payload on the Interna-tional Space Station (ISS) in coordination with the Payload Operations Integration Center (POIC) at NASA’s Marshall Space Flight Center. The SOC has been responsible for sending commands to and receiving data from the Science Flight Computer (SFC) on board ISS-CREAM. The ISS-CREAM data taking program interfaces with the POIC using the Telescience Resources Kit through the Software Toolkit for Ethernet Lab-Like Architecture developed by the Boeing Company. The command uplink and data downlink have been through the Track-ing and Data Relay Satellite System. We present the ISS-CREAM flight operations including ISS communications, SFC performance, etc

On-orbit Performance of the ISS-CREAM Calorimeter

International audienceCosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experi-ment is designed to study the composition and energy spectra of cosmic-ray particles from 10^12 to 10^15 eV. ISS-CREAM was launched and deployed to the ISS in August 2017. The ISS-CREAM payload employs a Silicon Charge Detector for charge measurements, Top and Bot-tom Counting Detector for electron-hadron separation and a low-energy trigger, a Boronated Scintillator Detector for additional electron-hadron separation, and a Calorimeter (CAL) for en-ergy measurements and a high-energy trigger. The CAL is constructed of 20 layers of tungsten plates interleaved with scintillating fiber ribbons read out by hybrid-photodiodes (HPDs) and densified carbon targets. Each CAL layer is made of 3.5 mm (1 X_0) thick tungsten plates alter-nating with fifty 0.5 mm thick and 1 cm wide scintillating fiber ribbons. Consecutive layers of fiber ribbons are installed orthogonal to each other. Energy deposition in the CAL determines the particle energy and provides tracking information to determine which segment(s) of the charge detectors to use for the charge measurement. Tracking for showers is accomplished by extrapolating each shower axis back to the charge detectors. The performance of the ISS-CREAM CAL during flight is presented

Track Reconstruction for ISS-CREAM Resulting in Improved Energy and Charge Resolutions

International audienceCosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) has taken 1.5 years of direct measurements of high-energy cosmic ray (HECR) particles for energies from 10$^{12}$ to 10$^{15}$ eV. HECR particle identification is significantly improved by tracking particle-detector interactions from the calorimeter (CAL) back to the Silicon Charge Detector (SCD) for charge determination. A track finding algorithm resistant to such issues as particle multiplicity, backscatter, and electronic noise will be outlined. Also, shown is the energy resolution improvement, and the resulting all particle spectrum, provided by ensuring good particle tracks. This allows ISS-CREAM to investigate how the energy distributions evolve, for protons all the way to iron nuclei, and will provide important information for models of galactic sources and HECR propagation

e/p Separation Study Using the ISS-CREAM Top and Bottom Counting Detectors

International audienceCosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) is an experiment for studying the origin, acceleration, and propagation mechanisms of high-energy cosmic rays. The ISS-CREAM instrument was launched on the 14th of August 2017 to the ISS aboard the SpaceX-12 Dragon spacecraft. The Top and Bottom Counting Detectors (TCD/BCD) are parts of the ISS-CREAM instrument and designed for studying electron and gamma-ray physics. The TCD/BCD each consist of an array of 20 × 20 photodiodes on a plastic scintillator. The TCD/BCD can separate electrons from protons by using the difference between the shapes of electromagnetic and hadronic showers in the high energy region. The Boosted Decision Tree (BDT) method, which is a deep learning method, is used in this separation study. We will present results of the electron/proton separation study and rejection power in various energy ranges

Simulation Status of the Top and Bottom Counting Detectors for the ISS-CREAM Experiment

International audienceThe Cosmic-Ray Energetics And Mass (CREAM) instrument for the International Space Station (ISS) is a detector for studying the origin, acceleration and propagation mechanism of high-energy cosmic rays. The ISS-CREAM instrument is scheduled to launch in 2017 to the ISS. The Top and Bottom Counting Detectors (TCD/BCD) are designed for studying electron and gamma-ray physics. The TCD/BCD are composed of a plastic scintillator and an array of photodiodes The active detection areas of the TCD/BCD are 500 $\times$ 500 mm$^2$ and 600 $\times$ 600 mm$^2$, respectively. The TCD/BCD were completed in 2015 and passed the environmental tests for safety in a space environment. After finishing these tests, the TCD/BCD were integrated with the payload. The TCD is located between the carbon target of the ISS-CREAM instrument and the calorimeter, and the BCD is located below the calorimeter. The TCD/BCD can distinguish between electrons and protons by using the different shapes between electromagnetic and hadronic showers in the high-energy region. We study the TCD/BCD performance in various energy ranges by using GEANT3 simulation data. Here, we present the status of the electron and proton separation study with the TCD/BCD simulation