2.3 Calculating Radiation Attenuation
19
be rigged to explode, so you are asked to determine the worst case. You calculate
that, if the box is made of lead, the highest-activity source it might contain is about
16,400 GBq or 16.4 TBq).
The TVL for Co-60 gammas in lead is about 5 cm. Fifteen cm of lead is 3 TVL,
so the dose rate will be reduced by a factor of 10
3 . Thus, the apparent activity of
16,400 MBq (shielded) is equivalent of 16,400 GBq, or 16.4 TBq, assuming that
the box in which the source is contained is made of solid lead.
You advise the Incident Commander that this is a high-activity source that, if
removed from its shielding, can be very dangerous to emergency responders.
References
1. Gollnick D (2011) Basic radiation protection technology, 6th edn. Pacific Radiation Corporation,
Altadena CA
2. Johnson T (2017) Introduction to health physics, 5th edn. McGraw Hill Education, New York
City
3. International Commission on Radiological Protection (2007) Annals of the ICRP Vol. 37 Nos.
2–4. The 2007 recommendations of the international commission on radiological protection.
Elsevier Ltd, Amsterdam
4. New York City (2010) Radiological response and recovery plan. New York City Office of
Emergency Management
5. Korir G, Karam P (2018) A novel method for quick assessment of internal and external radiation
exposure in the aftermath of a large radiological incident. Health Phys 115(2):235–251
6. ¸
Sahin D, ¸
Sahin MS, Kayrin K (2020) RadPro calculator online calculation utility. https://www.
radprocalculator.com/default.aspx. Accessed 11 May 2020
7. US Environmental Protection Agency (1988) Federal Guidance Report No. 11: Limiting Values
Of Radionuclide Intake And Air Concentration And Dose Conversion Factors For Inhalation,
Submersion, And Ingestion. Government Printing Office, Washington DC
19
be rigged to explode, so you are asked to determine the worst case. You calculate
that, if the box is made of lead, the highest-activity source it might contain is about
16,400 GBq or 16.4 TBq).
The TVL for Co-60 gammas in lead is about 5 cm. Fifteen cm of lead is 3 TVL,
so the dose rate will be reduced by a factor of 10
3 . Thus, the apparent activity of
16,400 MBq (shielded) is equivalent of 16,400 GBq, or 16.4 TBq, assuming that
the box in which the source is contained is made of solid lead.
You advise the Incident Commander that this is a high-activity source that, if
removed from its shielding, can be very dangerous to emergency responders.
References
1. Gollnick D (2011) Basic radiation protection technology, 6th edn. Pacific Radiation Corporation,
Altadena CA
2. Johnson T (2017) Introduction to health physics, 5th edn. McGraw Hill Education, New York
City
3. International Commission on Radiological Protection (2007) Annals of the ICRP Vol. 37 Nos.
2–4. The 2007 recommendations of the international commission on radiological protection.
Elsevier Ltd, Amsterdam
4. New York City (2010) Radiological response and recovery plan. New York City Office of
Emergency Management
5. Korir G, Karam P (2018) A novel method for quick assessment of internal and external radiation
exposure in the aftermath of a large radiological incident. Health Phys 115(2):235–251
6. ¸
Sahin D, ¸
Sahin MS, Kayrin K (2020) RadPro calculator online calculation utility. https://www.
radprocalculator.com/default.aspx. Accessed 11 May 2020
7. US Environmental Protection Agency (1988) Federal Guidance Report No. 11: Limiting Values
Of Radionuclide Intake And Air Concentration And Dose Conversion Factors For Inhalation,
Submersion, And Ingestion. Government Printing Office, Washington DC