The Nature of Statistical Fluctuations with Applications to Cosmic Rays

Measurement Techniques of Applied Radiochemistry

“…Because both are exposed to the same average cosmic ray flux, real fluctuations will tend to cancel. However, random fluctuations will be increased, and for short measurements this arrangement is actually a disadvantage (42).…”

“…The statistical laws governing the behavior of current-and charge-type ionization chambers are complicated by the variability of the ionization per particle; moreover, the distribution of ionization is generally unknown. Approximate treatments based on simplified assumptions regarding this distribution have been given (42), but in practice the precision is generally determined by repeating each measurement several times and calculating the standard or probable error by standard statistical formulas. Instruments of this type are most often used for radiation levels sufficiently high that random fluctuations are relatively small and may often be disregarded.…”

Analytical Procedure for Measurement of Long-Lived Radioactive Sulfur, S35, with Lauritzen Electroscope and Comparison of Electroscope with Special Geiger Counter

“…Since the accuracy of measuring activities of the order of background depends in part upon the reproducibility of this background, a Geiger counter is more accurate for these determinations than an electroscope. This deduction is based essentially upon the fact that the time variation in the number of cosmic and local rays entering a countér is less than the time variation in the total ionization produced by these same rays as measured by the electroscope (4,5,11). Actually the statistical variations in the background of the electroscope are somew'hat less than that of counters developed for the detection of soft beta-particles.…”

“…In numerous cases the errors resulting from the first two sources have been considerable; however, they are usually avoidable. The errors arising from the third and fourth sources have been subjected to mathematical analysis (4,5,11) and during routine radioactive analysis can be held to about 2%. Within readily recognizable limits, this error is essentially independent of the radioactivity present in the sample.…”