X-Ray Fluoresence Meter/Detector. Introduction Air monitoring data is useful for: *Assessing the...

X-Ray Fluoresence Meter/Detector


IntroductionIntroduction

Air monitoring data is useful for:Air monitoring data is useful for:** Assessing the health risks to the public and response Assessing the health risks to the public and response

workers.workers.

** Selecting personal protective equipment.Selecting personal protective equipment.

** Delineating areas where protection is needed.Delineating areas where protection is needed.

** Determining actual or potential effects on the environment.Determining actual or potential effects on the environment.

** Selecting actions to mitigate the hazards safely and Selecting actions to mitigate the hazards safely and effectively.effectively.


Toxic atmosphere monitoring is done to:Toxic atmosphere monitoring is done to:** identify airborne concentrations that could identify airborne concentrations that could

pose a toxic risk to response workers and pose a toxic risk to response workers and the public.the public.

** evaluate the need for and type of personal evaluate the need for and type of personal protective equipment.protective equipment.

• set up work zones or areas where set up work zones or areas where contaminants are or are not present. contaminants are or are not present.


• Characteristics of Air MonitoringCharacteristics of Air MonitoringTo be useful air monitoring instruments To be useful air monitoring instruments must be:must be:** Portable and rugged.Portable and rugged.

** Easy to operate.Easy to operate. ** Inherently safe.Inherently safe. ** Able to generate reliable and useful Able to generate reliable and useful

results.results.


The response time, sensitivity, selectivity, The response time, sensitivity, selectivity, accuracy and precision of an instrument are accuracy and precision of an instrument are important in evaluating the reliability and important in evaluating the reliability and usefulness of the data the instrument usefulness of the data the instrument generates. generates.


X-ray Fluorescence (XRF) is a nondestructive method

sample is irradiated by an intense x-ray beam, which causes the emission of fluorescent x-rays

emitted x-rays can either be detected using energy dispersive or wavelength dispersive detector

energies or wavelengths of emitted x-rays are used to identify elements present

Components present are quantified by x-ray intensity


sample can be excited by a x-ray source, by a radioisotope source, or by an electron beam

XRF uses x-rays as the primacy source primary source excites sample by knocking

out tightly bound electrons from the inner-shell orbital

Relaxation of excited atom to ground state is accompanied by the emission of fluorescent x-rays


X-rays emitted from excited sample strike detector


Principle of Operation: Principle of Operation:


elements present in sample identified by location of energy peaks along the horizontal axis

number of x-rays produced proportional to number of atoms present

quantitative elemental concentrations determined from intensities of energy peak


samples can be analyzed "as is" for most qualitative analysis and quantitative analysis

Some samples require sample preparation such as pelletizing or casting as fusion disk

Vacuum compatibility of sample depends upon element

Sample need not be conductive or insulating quantitative analysis samples should be

homogeneous with flat smooth surface Qualitative and qualitative elemental information

obtained from a bulk infinite thickness sample quality of results depends on calibration standards

References Cited

http://www.xrfcorp.com/http://www.xrfcorp.com/ Accessed 05/03/01 Accessed 05/03/01

http://ion.eas.asu.edu/descript_xrf.htmhttp://ion.eas.asu.edu/descript_xrf.htm Accessed Accessed 05/03/0105/03/01

NIOSH Manual of Analytical Methods NIOSH Manual of Analytical Methods (NMAM®), 4th ed.(NMAM®), 4th ed.DHHS (NIOSH) Publication 94-113 (August, DHHS (NIOSH) Publication 94-113 (August, 1994),1994),Cassinelli, M.E. & Cassinelli, M.E. & O'Connor, P.F. (pfo1@O'Connor, P.F. ([email protected])), Eds., Eds.

Bibliography

DiNardi Salvatore R. (1998) DiNardi Salvatore R. (1998) The The Occupational Environment-Its Evaluation Occupational Environment-Its Evaluation and Controland Control, AIHA, Fairfax, Virginia , AIHA, Fairfax, Virginia

Goetsch David L. (1999) Goetsch David L. (1999) Occupational Occupational Safety and Health for Technologists, Safety and Health for Technologists, Engineers, and ManagersEngineers, and Managers, Prentice Hall, , Prentice Hall, Upper Saddle River, New Jersey Upper Saddle River, New Jersey

X-Ray Fluoresence Meter/Detector. Introduction Air monitoring data is useful for: *Assessing the...

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