Alpha-particle spectroscopy
- Alpha-particle spectroscopy
One method for testing for (and measuring) many alpha emitters is to use alpha-particle spectroscopy. For methods for gamma rays and beta particles, please see gamma spectroscopy and liquid scintillation counting respectively.
Experimental methods
Counting using a source in a metal disk
It is common to place a drop of the test solution on a metal disk which is then dried out to give a uniform coating on the disk. This is then used as the test sample. If the thickness of the layer formed on the disk is too thick then the lines of the spectrum are broadened. This is because some of the energy of the alpha particles is lost during their movement through the layer of active material.
Liquid scintillation
An alternative method is to use internal liquid scintillation, where the sample is mixed with a scintillation cocktail. When the light emissions are then counted, some machines will record the amount of light energy per radioactive decay event. Due to the imperfections of the liquid scintillation method (such as a failure for all the photons to be detected, cloudy or coloured samples can be difficult to count) and the fact that random quenching can reduce the number of photons generated per radioactive decay, it is possible to get a broadening of the alpha spectra obtained through liquid scintillation. It is likely that these liquid scintillation spectra will be subject to a Gaussian broadening rather than the distortion exhibited when the layer of an active material on a disk is too thick.
Alpha spectra
From left to right the peaks are due to 209Po, 210Po, 239Pu and 241Am. The fact that isotopes such as 239Pu and 241Am have more than one alpha line indicates that the nucleus has the ability to be in different discrete energy levels (like a molecule can).
Wikimedia Foundation.
2010.
Look at other dictionaries:
spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… … Universalium
Gamma spectroscopy — The gamma ray spectrum of natural uranium, showing about a dozen discrete lines superimposed on a smooth continuum, allows the identification the nuclides 226Ra, 214Pb, and 214Bi of the uranium decay chain. Gamma ray spectroscopy is the… … Wikipedia
Rutherford backscattering spectroscopy — Rutherford backscattering spectrometry (RBS) is an analytical technique used in materials science. Sometimes referred to as high energy ion scattering (HEIS) spectrometry, RBS is used to determine the structure and composition of materials by… … Wikipedia
Fluorescence correlation spectroscopy — (FCS) is a common technique used by physicists, chemists, and biologists to experimentally characterize the dynamics of fluorescent species (e.g. single fluorescent dye molecules in nanostructured materials, autofluorescent proteins in living… … Wikipedia
Polonium — (] [cite journal author = Momoshima N., Song L.X., Osaki S.,Maeda Y., title = Biologically induced Po emission from fresh water journal =J Environ Radioact. year = 2002 volume = 63 issue = 2 pages = 187–197 doi =10.1016/S0265 931X(02)00028 0]… … Wikipedia
Spectrum analysis — also known as Emission Spectrochemical Analysis is the original scientific method of charting and analyzing the chemical properties of matter and gases by looking at the bands in their optical spectrum. The empirical laws of spectrum analysis are … Wikipedia
radiation measurement — ▪ technology Introduction technique for detecting the intensity and characteristics of ionizing radiation, such as alpha, beta, and gamma rays or neutrons, for the purpose of measurement. The term ionizing radiation refers to those… … Universalium
radioactivity — /ray dee oh ak tiv i tee/, n. Physics, Chem. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element. Also called activity. [1895… … Universalium
atom — /at euhm/, n. 1. Physics. a. the smallest component of an element having the chemical properties of the element, consisting of a nucleus containing combinations of neutrons and protons and one or more electrons bound to the nucleus by electrical… … Universalium
Atom — The atom is the smallest unit of an element that retains the chemical properties of that element. An atom has an electron cloud consisting of negatively charged electrons surrounding a dense nucleus. The nucleus contains positively charged… … Wikipedia
