A search for non-integral charge particles in cosmic rays

Large area proportional counters were developed and used to study the charge distribution of interacting particles incident at Durham in the near vertical direction. The experiment was operated in the search for non-integral charge particles in cosmic rays at sea level. The apparatus was sensitive to relativistic particles of charge in the range 2e/3 to 7e/3. No strong signal was obtained in the running time and the rate of non-integral charge particles was set as a limit. This limit was:- I < (4.2 ± 1.9)l0(^-9)cm(^-2)s(^-1)sr(^-1) A second experiment was developed to detect e/3 charge particles close to the core of extensive air showers at sea level. . The response of the detector for relativistic single muons was measured and the equivalent characteristics for relativistic e/3 quarks calculated. The change in response for the more energetic muons close to the air shower core was also measured and agreed with the calculated prediction. A system of electronics was constructed and was used in the two experiments and subsidiary investigations.