Narrow Air Showers of Cosmic Rays

A modular telescope facility to investigate the cosmic ray decoherence curve

“…Looking at the shape of the decoherence curve, two regions may be noted; the first one, for very small separation distances (from 0 to 4-5 m), has a steep slope, while the second region, for larger sepa- ration distances, is flatter. This is in agreement with what observed in early measurements [11][12][13], which however reported only a few data in this region. Roughly a factor 10 is seen in our conditions between the coincidence yields measured at d = 0.5 m and at d = 20 m.…”

“…Since that time, the coincidence counting rate of two cosmic ray detectors as a function of the separation between them has been measured under various conditions and up to large relative distances. Pioneering measurements were reported, among others, by Skobeltzyn [11], Prescott [12], and Wei and Montgomery [13]. More recently, measurements of the decoherence curve have been carried out in large underground experiments [14], being sensitive to muons with very high energy.…”

“…The interplay between the soft and the penetrating components, including their correlation within a cosmic ray shower, was discussed as early as 1949 by Cocconi [15], who already had realized that the fraction of electrons, with respect to the penetrating component, is not constant over the different regions of the shower, since the two components have a different angular spread in the production process. While the expected distribution of muon pairs is rather flat when their relative distance is decreased to zero, a sensible rise in the coincidence counting rate is instead observed at very small separation distances, and the showers that are responsible for this discrepancy were originally named narrow air showers [13]. This phenomenology has been investigated at different elevations and with different amounts of shielding above the detectors [12,13,16].…”

“…While the expected distribution of muon pairs is rather flat when their relative distance is decreased to zero, a sensible rise in the coincidence counting rate is instead observed at very small separation distances, and the showers that are responsible for this discrepancy were originally named narrow air showers [13]. This phenomenology has been investigated at different elevations and with different amounts of shielding above the detectors [12,13,16]. Narrow air showers may originate either by the electromagnetic components in very young cascades generated in air at large traversed atmospheric depths, i.e.…”

The Altitude and Angular Dependence of Cosmic-Ray Air Showers

“…13,14 This is particularly true for counter areas between 10 and 1000 cm 2 and for separations between 2 and 10 meters. All of the experimental arrangements used for the data of Fig.…”