ENERGY SPECTRA OF HEAVY PRIMARY NUCLEAR COSMIC RAYS

The instrument used in this experiment was a combination of two scintillation counters, two cerenkov counters, and a multiwire proportional counter hodoscope. The figure at left shows a cross section of the detector system.

The counters labeled T1 and T3 were identical 1 cm. thick scintillators, which were used to determine the charge of penetrating nuclei. T0 was a plastic Cerenkov counter with wave shifter while T2 was a 2 cm. thick liquid Cerenkov counter with Freon. It, too, contained a waveshifter.

The two Cerenkov counters combined provided a continous and overlapping velocity measurement for particles from 400 to about 2500 MeV/nucleon. Each of the counters were enclosed in a white light integration box to gain uniformity of signals over the entire counter area. An annular scintillator, surrounded the bottom of the detector stack and served to reject side showers.

The multiwire proportional counter hodoscope consisted of three chambers, designated MWPC A, B, and C in the scheme, each with wire grids in the x and y directions. The hodoscope determined the trajectory of the particle and also defined the geometrical factor of the instrument. It served to correct the pulse heights from the counters for angle of incidence and for small, residual non uniformities

Balloon launched on: 10/1/1975
Launch site: Muskogee, Oklahoma, US  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Winzen 593.316 m3 (12.70 microns Stratofilm)
Flight identification number: 117N
End of flight (L for landing time, W for last contact, otherwise termination time): 10/3/1975
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 36 h 20 m
Payload weight: 1696 kgs

• Chemical Composition of Cosmic Ray Iron Group Nuclei at About 1 GeV/nuc 15th International Cosmic Ray Conference, Vol. 1, p.248
• Composition of cosmic-ray nuclei from boron to nickel for 1200 to 2400 MeV per nucleon Astrophysical Journal, Part 1, vol. 294, July 15, 1985, p. 441
• Cosmic-ray elemental abundances from 1 to 10 GeV per AMU for boron through nickel Astrophysical Journal, Part 1, vol. 322, Nov. 15, 1987, p. 981
• Energy Spectra and Charge Composition of Cosmic-Ray Nuclei 24 < Z < 28 with Energy above 1 Gev/amu 16th International Cosmic Ray Conference, Vol. 12 p.57
• High resolution determination of elemental abundances for Z equals 8-28 at 1.2-2.4 GeV/n 17th International Cosmic Ray Conference, Vol. 2 p.54
• National Scientific Balloon Facility Annual Report FY 1978 National Center for Atmospheric Research, January 1979
• The abundances and energy spectra of cosmic ray iron and nickel at energies from 1 to 10 GeV per AMU Astrophysical Journal, Part 1, vol. 248, Sept. 1, 1981, p. 847
• The Mean-Mass of Cosmic-Ray NE, MG and SI at 1.0 Gev/amu 16th International Cosmic Ray Conference, Vol. 12 p.97
• Two cosmic-ray detectors with high charge and energy resolution in the GeV/nucleon range Nuclear Instruments and Methods in Physics Research, Volume 224, Issues 1-2, 1984, Pag. 247