B

B

atomic symbol for boron

Ba

atomic symbol for barium

background

1. In general the term background refers to the normal radionuclide concentration, radiation level, or instrument signal, in either the environment (environmental background) or the measuring instrument (instrument background), that occurs in the absence of the analyte or in the absence of any analyte con­tributed by a specified cause (e.g., con­tamina­tion in the environ­ment pro­duced by human activities, or analyte in a source derived from a test sample).
2. instrument background
3. baseline
4. environmental background

Note: Use of the unqualified term background may sometimes be a source of confusion.

backscatter(ing)

deflection of radiation by matter at any angle greater than 90° from the original direction of motion

backscatter peak

peak in a gamma-ray spectrum produced by photons scattered by Compton inter­actions in the materials surround­ing the detector

balance

device for measuring mass

barn (b)

traditional non-SI unit of cross section, equal to 10⁻²⁸ m²

Note: Although the barn is not an SI unit, it is accepted for use with the SI.

baseline

in a spectrum, the straight or curving line on which peaks and other features are superimposed

base quantity

“one of the quantities that, in a system of quantities, are conventionally accepted as functionally independent of one another” [VIM]
(cf. derived quantity)

base unit

unit of measurement for a base quantity (cf. derived unit)

Be

atomic symbol for beryllium

becquerel (Bq)

special name for the SI derived unit of activity, equal to 1 s⁻¹ (one nuclear transformation per second)

beta decay; β decay

nuclear decay in which the mass number of the nucleus remains unchanged and the neutron number changes; β⁻ decay, β⁺ decay, or electron capture

β⁻ decay

nuclear decay accompanied by the emission of an electron (β⁻-particle) from the nucleus

β⁺ decay

nuclear decay accompanied by the emission of a positron (β⁺ particle) from the nucleus

beta-emitting

capable of undergoing nuclear decay accompanied by the emission of a beta-particle

beta-emitter

beta-emitting radionuclide

beta-particle (β-particle)

electron (β⁻) or positron (β⁺) emitted from an atomic nucleus during certain types of radioactive decay

beta radiation

radiation consisting of beta-particles

Bh

atomic symbol for bohrium

Bi

atomic_symbol for bismuth

bias (of an estimator)

If X is an estimator for a parameter, θ, the bias of X equals the difference between the mean of X and θ, or μ_X − θ.

bias (of a measurement)

See systematic error

bias (of a measurement process)

persistent deviation of the mean result from the true value of the measurand (cf. precision)

bias (of sampling)

for a particular quantity that is a property of a body of material, the difference between the expected value of that quantity for a sample and a true value of the quantity for the lot

Note: The sampling bias depends on the manner in which the sample is taken.

bias (voltage)

for many types of radiation detector, a voltage applied to the detector that enables it to detect an ionizing event and to amplify the resulting signal

binomial distribution

Suppose N is a positive integer and p is a real number between 0 and 1. A random variable, X, has the binomial distribution with parameters N and p if

Pr(X = k) =

{

( N k )  pk(1 − p)N − k,     if k = 0, 1, 2, …, N, 0,     otherwise.

If a particular type of random experiment has two possible outcomes, called “success” and “failure,” and the probability of success in any trial of the experiment is p, then the binomial distribution describes the number of successes observed in N independent trials of the experiment.

bioassay

analysis of living organisms or their excreta

Bk

atomic symbol for berkelium

blank

1. artificial sample or source that has the form of a normal sample or source but contains little if any of the analyte (see also reagent blank, method blank)
2. analyte-free

blank correction

correction (typically negative) for the result of a chemical or radiochemical analysis, which is estimated by measuring a blank and which is intended to account for the effects of background radiation, contaminants, and/or interferences

blank sample

any of various types of real or artificial samples that contain little or none of an analyte, such as a method blank or a reagent blank

Note: Use of the term blank sample without qualification or explanation may tend to cause confusion.

blank source

source prepared to simulate a test source with none of the analyte present

blind sample

real or artificial sample, generally with well-characterized concentrations of analytes, introduced into a measurement process at a laboratory without informing the analyst of the analyte concentrations, for the purpose of evaluating the performance of the measurement process

 

When the identity of the sample as a blind sample is made known to the analyst, the sample is often called a single blind. When the identity of the sample as a blind sample is concealed from the analyst, the sample is often called a double blind.

blunder

mistake made by a person performing a measurement, which produces a substantial error in the result

Br

atomic symbol for bromine

branching decay

nuclear decay that can proceed in more than one way

branching fraction

in branching decay, the fraction of nuclei that decay in a given way

branching ratio

in branching decay, the ratio of the branching fractions for two given modes of decay