PI: W. Robert Binns

Affiliation: Washington University, St. Louis

Proposal Number: AO-99-05-OSS-038

Title: The Heavy Nuclei Explorer (HNX)

The primary objective of the Heavy Nuclei eXplorer (HNX) is to determine the origin of galactic cosmic rays by measuring the abundances of each individual element from neon through the actinides. Among the key questions that we will study are 1) the age of the cosmic rays and 2) the roles of volatility and first ionization potential at the cosmic ray source. We will accomplish this using two instruments, the Energetic Trans-Iron Composition Experiment (ENTICE) and the Extremely-heavy Cosmic-ray Composition Observer (ECCO). The ENTICE and ECCO experiments cover the charge (Z) ranges 10<=Z<=82 and 70<=Z<=100 respectively. A fraction of the events will be detected by both instruments, providing cross-calibration. The ECCO experiment utilizes glass track detectors, which require recovery for data analysis. ENTICE is an electronic instrument utilizing silicon solid-state detectors, Cherenkov counters, and scintillating optical fibers. The low flux of the heavy cosmic rays requires very large instruments; ENTICE will have an area of 4 m2, and ECCO will have an area of 23 m2. HNX will be launched as a free-flyer by Space Shuttle and recovered by Space Shuttle three years later.

Greg Tarle (CoI), University of Michigan

Nakahiro Yasuda (CoI), University of Tokyo

Hiroko Tawara (CoI), KEK--High Energy Accelerator Research Organization

Kouichi Ogura (CoI), Nihon University

Takayoshi Hayashi (CoI), Waseda University

Nobuyuki Hasebe (CoI), Waseda University

Jay Cummings (CoI), Washington University, St. Louis

James H. Adams (CoI), NASA/Marshall Space Flight Center

Tadayoshi Doke (CoI), Waseda University

Alan C. Cummings (CoI), California Institute of Technology

Louis M. Barbier (CoI), NASA/Goddard Space Flight Center

Richard A. Mewaldt (CoI), California Institute of Technology

C. Jake Waddington (CoI), University of Minnesota

Mark E. Wiedenbeck (CoI), Jet Propulsion Laboratory

Stephen M. Schindler (CoI), California Institute of Technology

Eric R. Christian (CoI), NASA/Goddard Space Flight Center

Edward C. Stone (CoI), California Institute of Technology

Richard A. Leske (CoI), California Institute of Technology

John Mitchell (CoI), NASA/Goddard Space Flight Center

Andrew J. Westphal (CoI), University of California, Berkeley

Martin H. Israel (CoI), Washington University, St. Louis

Paul L. Hink (CoI), Washington University, St. Louis