JACEE (Japanese-American Collaborative Emulsion Experiment) is a series of balloon-borne lead-emulsion chambers designed to directly measure the primary composition and spectra of cosmic rays at energies in the region of 1 TeV - 1000 TeV.

The chamber package is flown for several days at a high enough altitude that atmospheric effects are eliminated. Cosmic ray events (from the galaxy and beyond) interact in the chamber, producing a visible trail or shower in x-ray films and emulsion plates (sandwiched between the lead sheets). Once the package is recovered and the films developed, the events interacting in the chambers are catalogued, and their charge and energy determined. From the charge and energy flux, the spectrum for each species is derived.

The following pages describe the aspects of JACEE in greater detail:
Balloon Flights
JACEE-14 flew in December 1995 - January 1996. Information will be made available here as it comes in.
JACEE-13 was completed in Antarctica, January 1995; a news log and flight information are available. As data is analyzed from this flight, we hope to display it here. Other recent flights, JACEE-11/12 (1993) and JACEE-10 (1990), in Antarctica have pushed the exposure time to more than one week per flight.
General information on scientific ballooning is available from NASA/Wallops Flight Facility and also Goddard Space Flight Center.
A tutorial of the procedure, from initial cataloguing to the final spectrum.
Selected JACEE publications.
The members of the collaboration.
The custom hardware and software designed for JACEE.
Darkroom Techniques (How To Do It)
An attempt to archive valuable darkroom knowledge sitting in a little black notebook.
1995 Annual Progress Report to NSF
Describes work done under a grant from NSF's Office of Polar Programs: accomplishments during the past year and plans for the future.

The JACEE collaboration is also involved in high energy interaction studies. In layman's terms, we use the cosmic radiation as a high energy accelerator with random particle species and energy.

Work described here is supported in part by NSF grant OPP-9876428.

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* More info on particle astrophysics at UW.

R.J.W., E.L.Z.