Spectroscopy – Spectrometry – Difference – Distinction

In general, spectroscopy is the science of studying the interaction between matter and radiated energy while spectrometry is the method used to acquire a quantitative measurement of the spectrum. Spectroscopy (scopy means observation) does not generate any results. It is the theoretical approach of science. Spectrometry (metry means measurement) is the practical application where the results are generated. It is the measurement of the intensity of the radiation using an electronic device. Often these terms are used interchangeably, but every spectrometry is not spectroscopy (e.g. mass spectrometry vs. mass spectroscopy).

Distinction between X-rays and gamma rays

The distinction between X-rays and gamma rays is not so simple and has changed in recent decades. Yes, X-rays are being said to have lower energies, but this is not the rule and the main difference. According to the currently valid definition, X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

Gamma Spectroscopy

Source: wikipedia.org License: Public Domain

In general, gamma spectroscopy is the study of the energy spectra of gamma ray sources, such as in the nuclear industry, geochemical investigation, and astrophysics. Spectroscopes, or spectrometers, are sophisticated devices designed to measure the spectral power distribution of a source. The incident radiation generates a signal that allows to determine the energy of the incident particle.

Most radioactive sources produce gamma rays, which are of various energies and intensities. Gamma rays frequently accompany the emission of alpha and beta radiation. When these emissions are detected and analyzed with a spectroscopy system, a gamma-ray energy spectrum can be produced. Gamma rays from radioactive decay are in the energy range from a few keV to ~8 MeV, corresponding to the typical energy levels in nuclei with reasonably long lifetimes. As was written, they are produced by the decay of nuclei as they transition from a high energy state to a lower state. A detailed analysis of this spectrum is typically used to determine the identity and quantity of gamma emitters present in a sample, and is a vital tool in radiometric assay. The gamma spectrum is characteristic of the gamma-emitting nuclides contained in the source.

X-Ray Spectroscopy

X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray excitation. When an electron from the inner shell of an atom is excited by the energy of a photon, it moves to a higher energy level. Since the process leaves a vacancy in the electron energy level from which the electron came, the outer electrons of the atom cascade down to fill the lower atomic levels, and one or more characteristic X-rays are usually emitted. As a result, sharp intensity peaks appear in the spectrum at wavelengths that are a characteristic of the material from which the anode target is made. The frequencies of the characteristic X-rays can be predicted from the Bohr model. Analysis of the X-ray emission spectrum produces qualitative results about the elemental composition of the specimen.


Radiation Protection:

  1. Knoll, Glenn F., Radiation Detection and Measurement 4th Edition, Wiley, 8/2010. ISBN-13: 978-0470131480.
  2. Stabin, Michael G., Radiation Protection and Dosimetry: An Introduction to Health Physics, Springer, 10/2010. ISBN-13: 978-1441923912.
  3. Martin, James E., Physics for Radiation Protection 3rd Edition, Wiley-VCH, 4/2013. ISBN-13: 978-3527411764.
  5. U.S. Department of Energy, Instrumantation and Control. DOE Fundamentals Handbook, Volume 2 of 2. June 1992.

Nuclear and Reactor Physics:

  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. W.S.C. Williams. Nuclear and Particle Physics. Clarendon Press; 1 edition, 1991, ISBN: 978-0198520467
  6. G.R.Keepin. Physics of Nuclear Kinetics. Addison-Wesley Pub. Co; 1st edition, 1965
  7. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.
  8. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.
  9. Paul Reuss, Neutron Physics. EDP Sciences, 2008. ISBN: 978-2759800414.

See above:

Gamma Spectroscopy