Random numbers spring from alpha decay
Congruential random number generators, which are widely used in Monte Carlo simulations, are deficient in that the number they generate are concentrated in a relatively small number of hyperplanes. While this deficiency may not be a limitation in small Monte Carlo studies involving a few variables, it introduces a significant bias in large simulations requiring high resolution. This bias was recognized and assessed during preparations for an accident analysis study of nuclear power plants. This report describes a random number device based on the radioactive decay of alpha particles from a /sup 235/U source in a high-resolution gas proportional counter. The signals were fed to a 4096-channel analyzer and for each channel the frequency of signals registered in a 20,000-microsecond interval was recorded. The parity bits of these frequency counts (0 for an even count and 1 for an odd count) were then assembled in sequence to form 31-bit binary random numbers and transcribed to a magnetic tape. This cycle was repeated as many times as were necessary to create 3 million random numbers. The frequency distribution of counts from the present device conforms to the Brockwell-Moyal distribution, which takes into account the dead time of the counter (both the dead time and decay constant of the underlying Poisson process were estimated). Analysis of the count data and tests of randomness on a sample set of the 31-bit binary numbers indicate that this random number device is a highly reliable source of truly random numbers. Its use is, therefore, recommended in Monte Carlo simulations for which the congruential pseudorandom number generators are found to be inadequate. 6 figures, 5 tables.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 5254425
- Report Number(s):
- ANL/ES-95; TRN: 80-012068
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
RANDOMNESS
STATISTICS
ALPHA DECAY
COMPUTER CODES
MONTE CARLO METHOD
URANIUM 235
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
DECAY
EVEN-ODD NUCLEI
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MATHEMATICS
MINUTES LIVING RADIOISOTOPES
NUCLEI
RADIOISOTOPES
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES
990200* - Mathematics & Computers
653005 - Nuclear Theory- Radioactive Decay