Engineering topics

Justus, Alan Lawrence

Publications and source records attributed to Justus, Alan Lawrence.

5 records

DOE OSTI2019

Practical applications of the sigma factor alarm method within alpha CAMs utilizing either ROI, tail-fitting, or peak-fitting algorithms

Some test must be applied to the low-level count data from alpha continuous air monitors (CAMs) to determine if the count is statistically significant (i.e., significantly above background). The test should also automatically account for different levels of background (i.e., different ambient radon progeny concentrations). In other words, the method should be as sensitive as possible, automatically desensitizing when required, yet in such a manner as to not exceed some previously-chosen acceptable false-alarm rate. The test that has been historically utilized within many alpha CAMs to accomplish these goals is the so-called sigma factor approach.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2019

Difference distributions applicable to certain health physic's measurements

This paper discusses calculational methods for the determination of the difference distributions associated with certain health physics measurements. These measurements include the check source response counts relative to an initial reference count, the Albatross (i.e., HPI model 2080B) neutron tube counts relative to the gamma tube counts, and those that involve the use of the automatic background subtraction feature within portable health physics instrumentation. This paper therefore provides a technical basis for the necessary source strength of a check source in order to meet daily limits, the gamma field limitations of the HPI2080 Albatross, as well as the consequences of automatic background subtraction. Examples are provided that illustrate the methods for a few specific measurements.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2019

Multiple Facets of the Poisson Distribution Applicable to Health Physics Measurements

This paper discusses several ways to view the standard Poisson distribution as applied to health physics scaler counts. The intent is not so much to present calculational details but rather to present some underlying concepts. Examples are provided that illustrate the various concepts for several types of specific measurements. The concepts presented involve purely Poisson-based contributions to variance; extra-Poisson variance is presently ignored, and any counting system would be presumed to function properly and without counting loss.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2018

Simple grab sampling methods for the measurement of WL(Rn) and WL(Tn) concentrations

If one is air sampling for short -lived radon ( 222 Rn) progeny only, then it is the so-called working level concentration (WL) that is normally determined. Often, a so-called short-term grab air sample is utilized followed by gross α counting techniques. Care on the part of health physics personnel is required here, as is an uninterrupted work time.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2012

Dynamic radioactive particle source

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗