Component Of Extensive Air Showers Research Articles

A theoretical analysis of extensive air showers. III. Muon showers at large zenith angles

For Pt. II see abstr. A15896 of 1968. A theoretical analysis has been made of the muon component of extensive air showers incident at large angles to the vertical. Using the model described previously, calculations have been made of the expected numbers of muons reaching ground level as a function of threshold energy and zenith angle for primary particles of various energies. The data have been combined with alternative primary spectra of cosmic rays, with and without an enhanced contribution from heavy nuclei, to give the expected muon density spectra. It is found that the density spectrum is sensitive to the distribution of transverse momentum among the parents of the muons and to a lesser extent to the mass composition of the primaries. There is thus the possibility of deriving information about the mean transverse momentum, and perhaps setting limits on the mass composition, from a comparison with experiment.

The muon component of extensive air showers

The lateral distribution of the muon component of extensive air showers, and the variation in the total number of muons with shower size, have been studied for showers of sizes between 3 × 105 and 108 particles. The lateral distribution function is found to be in essential agreement with Griesen's formula, and the total number of muons is found to vary smoothly with shower size, as N0.75.

Note on multiple-core structure of the hadronic component of extensive air showers

Monte Carlo calculations on high-energy hadrons in extensive air showers have been performed, using various models of hadronic interaction and fragmentation. Frequencies of showers the hadronic component of which shows multiple-core structure are discussed in terms of primary particle and hadronic interaction parameters. The existence of a correlation between the primary mass composition and the frequencies of specified types of showers is demonstrated.

On the penetrating component of extensive air showers

The performance of a penetrating particle detector, originally designed to examine sidereal time variations, has been examined in conjunction with a small air shower array. It is found that the detector is sensitive to muons of energy > 700 MeV and to nuclear-active particles of energy > 15 GeV. Results of the Sydney group regarding the lateral structure function of nuclear-active particles are confirmed and shown to be valid up to 1 m core distance. Evidence is found in air showers of muon beams of energy > 6 GeV.

The Distribution of Energy in the Electron-Photon Component of Extensive Air Showers

An array of four water Cerenkov detectors of variable depth (maximum 3.4 radiation lengths) has been used to study extensive air showers of size 105 to 106 particles. The amount of Cerenkov light produced is a measure of the total electron track length in the detectors resulting from the incident spectrum of electrons and photons. The difference between the lateral structure function as measured by the Cerenkov detectors and the known particle density distribution function is therefore related to the presence of cascading or attenuation in the water. This was confirmed by observations with Geiger counters above and below a detector. These effects in the water are thus a measure of the energy of the electron-photon component. The energy carried by this component per shower electron was found to vary between 440 ± 60 MeV at a distance of 2 m from the shower axis and 195 ± 35 MeV at 12 m distance. The part of this energy which is carried by photons was found to be greater than that carried by electrons throughout most of the region examined.

On the High-Energy Electron-Photon Component in Extensive Air Showers

Using a large multiplate cloud chamber containing absorbers of 43 radiation lengths and 24 density detectors, characteristics of the electron-photon component of energy more than 1 Bev in extensive air showers (EAS) were studied at sea level. The size N of the selected shower extended from 2×10 4 to 5×10 6 . The obtained results were compared with data observed at 2770 m altitude. The main results are as follows: (1) The mean lateral distribution of the high-energy electron-photon component in the energy region 1∼20 Bev can be represented by the form ( r +2) - n , with n expressed by 2.6 E 0.24 , where the energy E and the distance from the axis γ are measured in the unit of Bev and of meters, respectively. (2) The energy flux at the high-energy electron-photon component in the core fluctuates very remarkably, and the ratio of the maximum value to the minimum value is greater than 100 in the showers with the same size. (3) The integral energy spectrum of the electron-photon component can be expressed by t...

Observations on Narrow Showers of Mesons below Ground

The decoherence curve of meson showers underground has been studied at depths of 37 and 61 metres water equivalent below sea level at separations from 0.4 m to 10 m, sufficient to overlap earlier measurements at 61 m.w.e. depth which extended to 320 m. The events recorded may be satisfactorily apportioned between events produced locally by energetic mesons, and the penetrating component of extensive air showers. The measurements are consistent with the interpretation that the multiple penetrating particles observed in cloud chambers underground represent the high particle density region of extensive showers of μ-mesons. The cross section for the production of penetrating showers by μ-mesons at 61 m.w.e. depth is (4 ± 2) × 10-31 cm2 nucleon-1, for an energy transfer of 8 GeV, in agreement with earlier measurements.

A Study on Nuclear-Active Component in Extensive Air Showers at Mountain Altitude

Nuclear-active component ( N -component) in extensive air shower was observed by means of a large multiplate cloud chamber and two standard neutron monitors which were installed in EAS array consisting of 16 density detectors. High energy N -particles above 10 Gev were observed by the multiplate cloud chamber, while N -particles of energy larger than 200 Mev were observed by the neutron monitor separately. The integral energy spectra of N-particles are shown to be represented by E -0.7±0.1 , E -1.1±0.2 and E -1.5±0.2 for the events observed at distances 0–5 m, 5–10 m and more than 10 m, respectively, from shower axis. And the integral energy spectrum of total N -particles is expressed by E -1.0±0.1 . The lateral distribution of N -particles above 10 Gev is obtained as r -1.4±0.2 with in 25 m from the axis. The lateral distribution of low energy N -particles is expressed by r -1.0±0.2 for the distance 5–30 m and the distribution becomes flatter within 5 m. These lateral distribution of each energy region c...

Energy Spectrum and Positive Excess of Muons in Cosmic-Ray Air Showers

A magnet spectrometer and an array of 15 large scintillator disks have been used to examine the distribution of the muon component of extensive air showers with respect to both energy and distance from the axis. An empirical function which has been found to be consistent with the observations is ${\ensuremath{\rho}}_{\ensuremath{\mu}}(N, r, \ensuremath{\ge}E)=\frac{14.4{r}^{\ensuremath{-}0.75}}{{(1+\frac{r}{320})}^{2.5}}{\left(\frac{N}{{10}^{6}}\right)}^{0.75}\left(\frac{51}{E+50}\right){\left(\frac{3}{E+2}\right)}^{a(r)},$ with $a(r)=0.14{r}^{0.37}$, where ${\ensuremath{\rho}}_{\ensuremath{\mu}}$ gives the average number of muons per square meter with energy exceeding $E$ Bev at $r$ meters from the axis of a shower that contains $N$ charged particles. According to this relation, the mean energy at sea level of the muons in air showers is 7 Bev, and they carry, in a shower of $N$ particles, an energy of $0.9\ifmmode\times\else\texttimes\fi{}{10}^{15}{(\frac{N}{{10}^{6}})}^{0.75}$ ev. The positive excess which has been observed in muons examined independently of air showers was not found in the muons detected in the air showers. We conclude that $\ensuremath{\pi}$-meson production dominates $K$-meson production by a factor of at least 10 in a region of meson energies about 10 Bev.

Longitudinal Distribution of Čerenkov Light from Extensive Air Showers

Measurements of the longitudinal distribution of the Cherenkov light associated with extensive cosmic showers of approximately l0/sup 15/-ev minimum energy are presented. Thcse measurements are compared with those of Bassi et al. resulting from analysis of the electron component of extensive air showers and with the distribution calculated by Monte Carlo techniques from Coulomb scattering of the shower electrons. (auth)

On the Electronic Component of Extensive Air Showers near the Axis

Using two multiplate cloud chambers and five density detectors consisting of 250 G.M.-counter hodoscopes, characters of the electronic component of extensive air showers were investigated for various distances from the axis in the range r ≤10 m at 2770 m altitude. The size N of the selected showers extended from 1×10 5 to 2×10 6 . The following results were obtained: (1) The integral size spectrum can be represented by a power law of the form N -γ , where the value of γ varies from 1.5 to 2.0 as the size increases. (2) The lateral density distribution of the high-energy electronic component with the energy \(E{\geqslant}1\) Bev fits well to that of the pure electronic shower with the age parameter s =1.4. (3) The ratio of the density of high-energy electrons and photons to that of all electrons is independent of the atmospheric depth. (4) The integral energy spectrum can be expressed by the E - n within the energy region 250 Mev \({\leqslant}E{\leqslant}1\) Bev, and the value of n shifts from 0.7 to 1.2 w...

The high-energy nuclear active component of extensive air showers

An attempt was made to study nuclear cascades statistically in extensive air showers at sea level. Pulse ionization chambers placed under a combined absorber were used to register nuclear active particles and to determine their energy. The measured spectrum of extensive air showers shows a maximum at N = 2.5 x 10/sup 4/ The spatial distribution of axes proved practically uniform in the circle R = 2.5 m. (A.C.)

Underground studies of μ-meson component in extensive air showers

If detailed information on the mu -meson component is obtained, the development of the nucleon cascade in the atmosphere will be better understood. When the air shower hits the ground, there remain mu mesons which are not absorbed and penetrate into the ground. Observations at various underground depths have been made at various poirts. Results of experiments by Cornell, London, and Yaizer groups are summarized. The Cornell group found mu mesons with a sea-level energy of ~600 Bev penetrated ~ 1600 mwe. (A.C.)

Investigation of extensive air showers containing nuclear active particles

The exponent of the density spectrum of the electronic component of extensive air showers containing nuclear active particles was determined to be γ=1.34±0.08 assuming that the density of nuclear active particles is proportional to the density of electrons in air showers. The agreement of the exponent found in the present experiment with that determined earlier for extensive air showers ( γ=1.34±0.02) with the same arrangement, which however, consisted only of the electron detectors supports the above assupmtion. From this it follows that the density spectrum of nuclear active particles has the form of a power law with an exponent approximately equal to γ. Furthermore, the decoherence curve between the electron and nuclear active particle detectors was measured. The experimental results are briefly discussed.

On the Lateral Distribution of the Electron Component in Extensive Air Showers

Apparatus of wide span made it possible to measure the lateral distribution of the electron component in air showers. The result shows that the shape of the lateral distribution is practically independent of the shower sizes and altitudes at which observations were made, in agreement with the Nishimura- Kamatu (N-K) function of age 1.3. The results of the investigation are graphically shown. (A.C.)

On the photon component of extensive air showers

Extensive air shower measurements carried out simultaneously with counter batteries of different areas are reported. All the four counter batteries were covered with absorbers of different materials and thicknesses. The spectrum of the effective density (i. e. that of the primaries capable of producing at least one ionizing secondary beneath the absorber) turns out to vary with the material and thickness of the absorber. This means that the transition effect appreciably depends on the nature of showers slected with different counter areas.

Observations on the Penetrating Component of Extensive Air Showers

The variation in the composition of the penetrating component of extensive air showers at sea-level has been investigated as a function of shower density. The proportion of N-particles in the penetrating component was observed to decrease as the shower density decreased. It is suggested that this behaviour is due to the filtering action of the atmosphere on the more absorbable particles in the nuclear cascade which has passed maximum development.

Ionization Chamber Measurements at 10 600 Feet of the Absorption of theNComponent in Carbon and Hydrocarbon

A detector consisting of a lead-shielded ionization chamber with Geiger counters above and below the chamber is described. The charged $N$ component of energy of several tens of Bev is detected.The absorption of the charged $N$ component in carbon is much smaller than that predicted from the absorption in air. This phenomenon may be explained by the fact that $\ensuremath{\pi}$ mesons or other unstable particles which are produced in nuclear interactions can give rise to further nuclear interactions.Approximate values for the interaction mean free path of $N$ rays in carbon have been obtained. These values depend on the number of shielded counters below the ionization chamber which are struck. For zero counters discharged, the mean free path is 136\ifmmode\pm\else\textpm\fi{}12 g ${\mathrm{cm}}^{\ensuremath{-}2}$ and seems to decrease as the requirement on the number of shielded counters struck is increased. The interaction mean free paths in carbon are compared to previous results in lead.The absorption of the $N$ component in oil indicates a cross section of the hydrogen nucleus much smaller than that corresponding to the range of nuclear forces.Events with large pulses from the ionization chamber or with multiple discharge of shielded counters below the chamber are more likely to be associated with the nucleonic component of extensive air showers.

On the Theory of the Angular and Lateral Spread of the Nucleon Component of the Cosmic Radiation

The three-dimensional development of the nucleon component of extensive air showers is investigated. A vectorial diffusion equation is derived for the phase-space distribution of the nucleons, and solved as far as required to determine the mean square angular deviation, and the mean square distance from the shower axis. Account is taken of the variation of density in the atmosphere, and numerical results are obtained for all altitudes. These are exhibited graphically. The lateral spread of the nucleon cascade in lead is also determined, and the results tabulated. A full discussion is given of the significance of the numerical values obtained.

The Electronic Component in Extensive Air Showers

The Electronic Component in Extensive Air Showers