Deep Dose Equivalent – Shallow Dose Equivalent

In general, the ICRP defines operational quantities for area and individual monitoring of external exposures. The operational quantities for area monitoring are:

  • Ambient dose equivalent, H*(10). The ambient dose equivalent is an operational quantity for area monitoring of strongly penetrating radiation.
  • Directional dose equivalent, H’ (d,Ω). The directional dose equivalent is an operational quantity for area monitoring of weakly penetrating radiation.

The operational quantities for individual monitoring are:

  • Personal dose equivalent, Hp(0.07). The Hp(0.07) dose equivalent is an operational quantity for individual monitoring for the assessment of the dose to the skin and to the hands and feet.
  • Personal dose equivalent, Hp(10). The Hp(10) dose equivalent is an operational quantity for individual monitoring for the assessment of effective dose.

Special Reference: ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2-4).

Deep Dose Equivalent and Shallow Dose Equivalent

Personal Dose Equivalent – Hp(10) – Hp(0.07)

Generally, the personal dose equivalent, Hp(d), is an operational quantity for individual monitoring. According to the ICRP, the personal dose equivalent is defined as:

ICRP Publication 103:

“The dose equivalent in soft tissue (commonly interpreted as the ‘ICRU sphere’) at an appropriate depth, d, below a specified point on the human body. ”

The personal dose equivalent is given the symbol Hp(d). Two common operational quantities for individual monitoring defined by the ICRP are:

  • Personal dose equivalent, Hp(0.07). The Hp(0.07) dose equivalent is an operational quantity for individual monitoring for the assessment of the dose to the skin and to the hands and feet.
  • Personal dose equivalent, Hp(10). The Hp(10) dose equivalent is an operational quantity for individual monitoring for the assessment of effective dose.

As can be seen, various depths can be used. The personal dose equivalent, Hp(d), can be assessed indirectly with a thin, tissue equivalent detector (radiation dosimeter) that is worn at the surface of the body and covered with an appropriate thickness of tissue equivalent material. The specified point, d, is normally taken to be where the radiation dosimeter is worn.

For assessment of superficial organs and the control of equivalent dose, depths of 0.07 mm for skin and 3 mm for the lens of the eye are employed, and the personal dose equivalents for those depths are denoted by Hp(0.07) and Hp(3), respectively. Hp(0.07) is also called the shallow dose equivalent.

For the assessment of deep organs and the control of effective dose, Hp(10) with a depth d = 10 mm is chosen. Hp(10) is also called the deep dose equivalent. If the personal dosimeter is worn on a position of the body representative of its exposure, at low doses and under the assumption of a uniform whole-body exposure, the value of Hp(10) provides an effective dose value sufficiently precise for radiological protection purposes. Neutron and gamma radiations contribute to both deep and shallow dose, but beta radiation is completely absorbed in the skin and therefore contributes to shallow dose only.

 

Radiation Measuring and Monitoring - Quantities and Limits

References:

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.
  4. U.S.NRC, NUCLEAR REACTOR CONCEPTS
  5. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.

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:

Radiation Monitoring