Extremely Energetic Cosmic-Ray Event

Abstract

observed until the vial was opened.4. Composition of the radioactive gas. Gas chromatography with charcoal and silica gel columns was used to analyze 1 the chemical composition of the radioactive gas liberated from 9.5-mg/cm 2 polyethylene. The composition was found to be 57% methane, 36% acetylene, 6% ethylene, and 1 % ethane. No CO or C0 2 was observed.Absolute measurements of the C X2 {p,pn)C n cross section may have been affected by the loss of C 11 in those cases where thin plastic targets were used. Recent measurements in the Bev region 2 ' 3 have used polystyrene targets sufficiently thick so that the correction is less than 1 %. The loss effect may also account for some of the discrepancies in the C 12 (p, pn)C n / Al 27 (/>, 3/m)Na 24 cross-section ratios which have been reported.The authors wish to acknowledge helpful discussions with and the assistance of R.

Astrophysical origins of ultrahigh energy cosmic rays

“…The existence of primary particles with energies greater than 10 18 eV was established by the observation of one shower with more than 10 9 particles. Soon afterwards, this technique flourished with measurements of ultra high energy cosmic rays (UHECRs) with the Volcano Ranch experiment in the 60 s [10,11,12], as well as with several other arrays, such as Haverah Park in England [13], Yakutsk in Russia [14,15], the Sydney University Giant Airshower Recorder in Australia (SUGAR) [16], and the Akeno Giant Air Shower Array (AGASA) in Japan [17,18].…”

High energy physics in the atmosphere: phenomenology of cosmic ray air showers

“…The muon bremsstrahlung cross section is suppressed by a factor of (m e /m µ ) 2 with respect to electron bremsstrahlung, see Eq. (23). Since the radiation length for air is about 36.7 g/cm 2 , and the vertical atmospheric depth is 1000 g/cm 2 , muon bremsstrahlung is of negligible importance for vertical air shower development.…”

“…The first measurements of ultra high energy cosmic rays were carried out by Linsley at Volcano Ranch (35 • 09 ′ N, 106 • 47 ′ W) in the late 1950's [23] using an array of scintillation counters. More recent experiments using surface detection techniques include Haverah Park in England (53 • 58 ′ N, 1 • 38 ′ W) [24], Yakutsk in Russia (62 • N, 130 • E) [25], the Sydney University Giant Airshower Recorder (SUGAR) in Australia (30 • 32 ′ S, 149 • 43 ′ E) [26], and the Akeno Giant Air Shower Array (AGASA), about 100 km west of Tokyo (38 • 47 ′ N, 138 • 30 ′ E) [27,28].…”

Summary: ZeV air showers where do we stand?

“…Sixteen of them are from four array experiments, one from Volcano Ranch [52], six from Haverah Park [53], one from Yakutsk array [54] and eight from AGASA [55]. The other event, which is the highest energy event observed, was detected with Fly's Eye [56], a different detector concept that measures the fluorescence light from nitrogen as the shower develops in the atmosphere.…”