Measurement of the νe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)×106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Δm2=7.59-0.21+0.19×10 -5eV2 and θ=34.4-1.2+1.3degrees

Causes of failing the draft ANSI Standard N13. 30 radiobioassay performance criterion for minimum detectable amount

The test methods used for PNL bioassay performance tests were evaluated by comparing the MDA based on performance tests results with MDA calculated by PNL using the bioassay laboratory's own quality control (QC) data. Two in vitro laboratories and two in vivo laboratories were studied and a correlation between the performance test MDA estimates and QC data was demonstrated. However, it was often necessary to examine the QC data to identify important characteristics of the blank distribution that affect the MDA calculation. Since the MDA equation must be based on the specific analysis and calculational methods of the procedure evaluated. Even when the correct MDA equation is applied, the MDA calculated will have a relatively large confidence interval when only a few replicates are used to estimate the standard deviation. For this reason, a relatively precise estimate of the MDA is generally only available when Poisson statistics may be applied. It was concluded that performance testing alone cannot provide all the information necessary to make an accurate estimate of the measurement process MDA. Review of the laboratory's QC data and the entire measurement procedure will be necessary. Specific recommendations for changes to draft ANSI N13.30 Performance Criteria for Radiobioassay'' are given. 10 refs., 18 figs., 11 tabs

Performance testing of radiobioassay laboratories: In vitro measurements, fecal study report

This study evaluated nine radiobioassay laboratories; performances in analyzing fecal samples to determine the samples' levels of radioactivity. A total of 135 artificial fecal samples were sent to nine laboratories. Each laboratory received five samples spiked with 9. 58 pCi of /sup 239/Pu, five samples spiked with 1.13 pCi /sup 239/Pu, and five unspiked blank samples. Four of the laboratories returned data for all samples; four reported they were unable to complete the analyses; one analyzed six samples (three blanks and three of the lower activity samples). Results reported by the laboratories were analyzed by statistical methods specified in the draft standard for relative bias, relative precision, and minimum detectable activity (MDA). The calculated relative biases of all laboratories were well within the criteria of the standard (/minus/0.25 to +0.5). Biases for three laboratories were about 5% and the two others were within +-20%. Relative precision statistics for all participating laboratories were lower than the acceptance criteria of the standard (40%). Relative precision was less than 15% for one laboratory; for two others, it was less than 10%; and for the remaining two, it was less than 5% of the acceptance criteria. For the MDA criterion, four of the five laboratories passed. For all four of the passing laboratories, the entire 90% confidence interval was less than the specified acceptable minimum detectable amount (acceptable MDA) of 1 pCi. for the fifth laboratory, the MDA was 80% above the acceptable MDA specified in the draft standard. 16 refs., 3 figs., 3 tabs

Experience with NQA-1 quality assurance standards applied to in vitro bioassay

On June 1, 1990, the large (about 4000 samples per year) excreta bioassay program at the Hanford Site ceased abruptly when the contract with the bioassay laboratory was terminated. An intense, high-priority effort was begun to replace the services on an interim basis until a new contract could be procured. Despite the urgency to get the excreta bioassay program going again, the Hanford Internal Dosimetry Program was constrained to use only labs that could meet stringent quality assurance (QA) requirements, even during the interim period. The QA requirements were based on NQA-1 with selected additions from the Environmental Protection Agency's QAMS 005/80 (EPA 1983) and the American Society for Testing and Materials' C 1009-83 (ASTM 1984). This constraint was driven both by legal reasons and by the Hanford Site contractors and workers not wanting the quality of the data to be sacrificed. Finding labs that could (1) handle the large throughput, (2) meet the technical requirements, and (3) pass the QA audit proved more difficult than first anticipated. This presentation focuses on the QA requirements that the labs had to meet and how those very broad requirements were applied specifically to excreta bioassay. 5 refs

Recommended procedures for performance testing of radiobioassay laboratories: Volume 3, In vivo test phantoms

Draft American National Standards Institute (ANSI) Standard N13.30 (Performance Criteria for Radiobioassay) was developed for the US Department of Energy and the US Nuclear Regulatory Commission to help ensure that bioassay laboratories provide accurate and consistent results. The draft standard describes the procedures necessary to establish a bioassay performance-testing laboratory and program. The bioassay performance-testing laboratory will conduct tests to evaluate the performance of service laboratories. Pacific Northwest Laboratory helped develop testing procedures as part of an effort to evaluate the draft ANSI N13.30 performance criteria by testing the existing measurement capabilities of various bioassay laboratories. This report recommends guidelines for the preparation, handling, storage, distribution, shipping, and documentation of test phantoms used for calibration of measurement systems for direct bioassay. The data base and recommended records system for documenting radiobioassay performance at the service laboratories are also presented

Comparisons of uniform and discrete source distributions for use in bioassay laboratory performance testing

The Pacific Northwest Laboratory (PNL) is sending a torso phantom with radioactive material uniformly distributed in the lungs to in vivo bioassay laboratories for analysis. Although the radionuclides ultimately chosen for the studies had relatively long half-lives, future accreditation testing will require repeated tests with short half-life test nuclides. Computer modeling was used to simulate the major components of the phantom. Radiation transport calculations were then performed using the computer models to calculate dose rates either 15 cm from the chest or at its surface. For /sup 144/Ce and /sup 60/Co, three configurations were used for the lung comparison tests. Calculations show that, for most detector positions, a single plug containing /sup 40/K located in the back of the heart provides a good approximation to a uniform distribution of /sup 40/K. The approximation would lead, however, to a positive bias for the detector reading if the detector were located at the chest surface near the center. Loading the /sup 40/K in a uniform layer inside the chest wall is not a good approximation of the uniform distribution in the lungs, because most of the radionuclides would be situated close to the detector location and the only shielding would be the thickness of the chest wall. The calculated dose rates for /sup 60/Co and /sup 144/Ce were similar at all calculated reference points. 3 refs., 5 figs., 10 tabs

Urine sample collection protocols for bioassay samples

In vitro radiobioassay analyses are used to measure the amount of radioactive material excreted by personnel exposed to the potential intake of radioactive material. The analytical results are then used with various metabolic models to estimate the amount of radioactive material in the subject's body and the original intake of radioactive material. Proper application of these metabolic models requires knowledge of the excretion period. It is normal practice to design the bioassay program based on a 24-hour excretion sample. The Hanford bioassay program simulates a total 24-hour urine excretion sample with urine collection periods lasting from one-half hour before retiring to one-half hour after rising on two consecutive days. Urine passed during the specified periods is collected in three 1-L bottles. Because the daily excretion volume given in Publication 23 of the International Commission on Radiological Protection (ICRP 1975, p. 354) for Reference Man is 1.4 L, it was proposed to use only two 1-L bottles as a cost-saving measure. This raised the broader question of what should be the design capacity of a 24-hour urine sample kit

Recommended procedures for performance testing of radiobioassay laboratories: Volume 2, In vitro samples

Draft American National Standards Institute (ANSI) Standard N13.30 (Performance Criteria for Radiobioassay) was developed for the US Department of Energy and the US Nuclear Regulatory Commission to help ensure that bioassay laboratories provide accurate and consistent results. The draft standard specifies the criteria for defining the procedures necessary to establish a bioassay performance-testing laboratory and program. The bioassay testing laboratory will conduct tests to evaluate the performance of service laboratories. Pacific Northwest Laboratory helped develop testing procedures as part of an effort to evaluate the performance criteria by testing the existing measurement capabilities of various bioassay laboratories. This report recommends guidelines for the preparation, handling, storage, distribution, shipping, and documentation of in vitro test samples (artificial urine and fecal matter) for indirect bioassay. The data base and recommended records system for documenting radiobioassay performance at the service laboratories are also presented. 8 refs., 3 tabs

Extremity dosimetry at US Department of Energy facilities

A questionnaire on extremity dosimetry was distributed to DOE facilities along with a questionnaire on beta dosimetry. An informal telephone survey was conducted as a follow-up survey to answer a few additional questions concerning extremity monitoring practices. The responses to the questionnaire and the telephone survey are summarized in this report. Background information, developed from operational experience and a review of the current literature, is presented as a basis for understanding the information obtained by the survey and questionnaire

Application of the generic ANSI N13. 30 minimum detectable activity equation to multichannel analysis

This paper addresses the concepts of the decision level (L{sub c}) and the minimum detectable activity (MDA) as they pertain to the interpretation of direct in vivo measurements. The approach is an extension of the methods found in the bioassay performance criteria of the draft ANSI Standard N13.30 Performance Criteria for Radiobioassay.'' 3 refs., 2 tabs