Improvements in the sensitivity of screen-type X-ray films for cascade showers and the charge resolution for heavy ions

Kobayashi, Tadashi; Fujii, Masami; Nishimura, Jun; Taira, T.; Aizu, H.; Komori, Y.

doi:10.1007/bf02812490

Cited by 4 publications

(4 citation statements)

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“…We picked up events with zenith angle less than 60 • . The detection threshold of the X-ray film, although it depends on the accumulated background tracks and fog in the film, is ∼500 GeV for Sakura type-N X-ray film used before 1984, ∼800 GeV for Fuji #200 Xray film and ∼200 GeV for screen type X-ray films such as Fuji G8-RXO, G12-RXO, HR8-HA30, HR12-HA30 used on and after 1984 [28].…”

Section: Scanning Methodsmentioning

confidence: 99%

Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

et al. 2006

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We have observed atmospheric gamma rays from 30 GeV to 8 TeV, using emulsion chambers at balloon altitudes, accumulating the largest total exposure in this energy range to date, ST 6:66 m 2 sr day. At very high altitudes, with residual overburden only a few g cm ÿ2 , atmospheric gamma rays are mainly produced by a single interaction of primary cosmic rays with overlying atmospheric nuclei. Thus, we can use these gamma rays to study the spectrum of primary cosmic rays and their products in the atmosphere. From the observed atmospheric gamma-ray spectrum, we deconvolved the primary cosmic-ray proton spectrum, assuming appropriate hadronic interaction models. Our deconvolved proton spectrum covers the energy range from 200 GeV to 50 TeV, which fills a gap in the currently available primary cosmic-ray proton spectra. We also estimated the atmospheric muon spectrum above 30 GeV at high altitude from our gamma-ray spectrum, almost without reference to the primary cosmic rays, and compared the estimated flux with direct muon observations below 20 GeV.

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Section: Scanning Methodsmentioning

confidence: 99%

Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

et al. 2006

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“…The corresponding tracks in the adjacent emulsion plate are located by using microscopes. The detection threshold of the X-ray film is 500 GeV for Sakura type-N X-ray film used before 1984, 750 GeV for Fuji #200 X-ray film, and 250 GeV, 200 GeV, 150 GeV for screen type Xray films of Fuji G8-RXO, G12-RXO, and GS-RXO used from 1984 to 1988 (Kobayashi et al 1991). After 1988 we used screen type X-ray films of HR8-HA30, HR12-HA30, and HR16-HA30.…”

Section: Detectormentioning

confidence: 99%

“…Figure 2 shows the result of the characteristic curves of different type of X-ray films. Since the detection threshold of the net darkness on the Xray films with naked eye is 0.1 (Kobayashi et al 1991), the electron densities on the emulsion plates at the X-ray film detection threshold correspond to 0.9×10 5 cm −2 for HR16-HA30, 1.2×10 5 cm −2 for HR12-HA30, 2.6×10 5 cm −2 for HR8-HA30, and 4.0×10 5 cm −2 for Fuji #200 X-ray films. These electron densities are compatible with the shower track densities with emulsion chambers at the shower maximum of electrons with energies of 140 GeV, 180 GeV, 450 GeV, and 750 GeV, respectively (see Fig.…”

Section: Detectormentioning

confidence: 99%

“…The efficiency C eff for detecting electro-magnetic showers in emulsion chambers have been studied to be essentially 100 % above the threshold energy for naked-eye scanning of Xray films (Kobayashi et al 1991, and references therein). The detection efficiency for HR16-HA30 was also tested by using emulsion chambers exposed to the 200 GeV electron beam at CERN-SPS.…”

Section: Energy Determinationmentioning

confidence: 99%

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OBSERVATIONS OF HIGH-ENERGY COSMIC-RAY ELECTRONS FROM 30 GeV TO 3 TeV WITH EMULSION CHAMBERS

Kobayashi

Komori

Yoshida

et al. 2012

ApJ

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We have performed a series of cosmic-ray electron observations using the balloon-borne emulsion chambers since 1968. While we previously reported the results from subsets of the exposures, the final results of the total exposures up to 2001 are presented here. Our successive experiments have yielded the total exposure of 8.19 m 2 sr day at the altitudes of 4.0 − 9.4 g cm −2 . The performance of the emulsion chambers was examined by accelerator beam tests and Monte-Carlo simulations, and the on-board calibrations were carried out by using the flight data. In this work we present the cosmic-ray electron spectrum in the energy range from 30 GeV to 3 TeV at the top of the atmosphere, which is well represented by a power-law function with an index of −3.28±0.10. The observed data can be also interpreted in terms of diffusive propagation models. The evidence of cosmic-ray electrons up to 3 TeV suggests the existence of cosmicray electron sources at distances within ∼ 1 kpc and times within ∼1×10 5 yr ago.Subject headings: cosmic rays: electrons, origin -balloons -supernova remnants 1 In this paper, the term "electrons" is used for the sum of particles regardless of charge. When we must identify the charge, we will use the terms "negative electrons" or "positrons".

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Determination of Z/β for strange quark matter candidates with CR-39 track detector

Fujii

Saad

Hatano

et al. 2001

Radiation Measurements

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Improvements in the sensitivity of screen-type X-ray films for cascade showers and the charge resolution for heavy ions

Cited by 4 publications

References 10 publications

Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

OBSERVATIONS OF HIGH-ENERGY COSMIC-RAY ELECTRONS FROM 30 GeV TO 3 TeV WITH EMULSION CHAMBERS

Determination of Z/β for strange quark matter candidates with CR-39 track detector

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