3 h module
Download
Skip this Video
Download Presentation
3 H Module

Loading in 2 Seconds...

play fullscreen
1 / 31

3 H Module - PowerPoint PPT Presentation


  • 458 Views
  • Uploaded on

3 H Module Objectives To understand the physical nature of 3 H. To understand that 3 H is both an internal and external radiation hazard. To understand the need to utilize shielding.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '3 H Module' - benjamin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
3 h module
3H Module

Objectives

  • To understand the physical nature of 3H.
  • To understand that 3H is both an internal and external radiation hazard.
  • To understand the need to utilize shielding.
  • To recognize that special procedures and protective measures are required when using activities greater than 100 mCi.
isotopes tritium 3 h
IsotopesTritium (3H)
  • The Maximum beta energy is 0.018 MeV.
  • It is a pure beta emitter (100 of the radiation emitted is beta particles)
  • The number of betas emitted per second = number of decays per second (for 1 mCi, 3.7 x 107 betas emitted)
isotopes tritium 3 h3
IsotopesTritium (3H)
  • The half-life is 12.28 years
  • The Average beta energy is 0.006 Mev or 6 keV.
  • The range of the most energetic tritium beta particles is only about 5 mm in air or 5 mm in water or soft tissue.
  • 3HCannot be detected with a Geiger Counter
  • 3H Cannot be detected by a dosimeter badge
isotopes tritium 3 h4
IsotopesTritium (3H)
  • The Annual limit of intake via ingestion is 80 mCi. (this means that a total burden in the body of 80 mCi from ingestion alone will give a 5 Rem dose).
  • Annual limit of intake via inhalation is 80 mCi. (this means that a total burden in the body from the lungs alone of 80 mCi will give a 5 Rem dose).
isotopes tritium 3 h5
IsotopesTritium (3H)
  • Three to four hours after intake, ingested, inhaled or absorbed tritiated water is uniformly distributed in all body water(1).
  • On average, tritiated water is eliminated with a 10-day biological half-life(1). This can be shortened with an increase of liquid intake (up to 20 liters), or in severe cases, by using dialysis machines.
  • ICRP Publication 30, Part 1, Limits for Intakes of Radionuclides by Workers, Pergamon Press, Oxford, 1979.
  • ICRP Publication 10, Recommendations of the International Commission on Radiological Protection, Pergamon Press, London, 1968.
isotopes tritium 3 h6
IsotopesTritium (3H)
  • The biological incorporation (uptake) of airborne HTO (tritiated water) can be extremely efficient:
    • up to 99% of inhaled HTO is taken into the body by the circulating blood.
    • Ingested liquid HTO is also almost completely absorbed by the gastrointestinal tract and quickly appears in the blood stream. Within minutes, it can be found in varying concentrations in the organs, fluids, and tissues of the body.
    • Skin absorption of airborne HTO is also important, especially during hot weather, because of the normal movement of water through the skin. For skin temperatures between 30 and 40EC, the absorption of HTO is about 50% of that for HTO by inhalation (assuming an average breathing rate associated with light work, 20 L/min). No matter how it is absorbed, the HTO will be uniformly distributed in all biological fluids within one to two hours..
isotopes tritium 3 h7
IsotopesTritium (3H)
  • Contamination is controlled and surveyed by wipe test/liquid scintillation counting.
  • For tritium, the liquid scintillation counter has a maximum efficiency of ~ 50% (meaning, at best, only ~1/2 of the betas are counted)
isotopes tritium 3 h wipe tests
IsotopesTritium (3H)Wipe Tests

Standard industry practice 100 cm2

100 cm2

12” to 14”

4” x 4”

isotopes tritium 3 h liquid scintillation counters
IsotopesTritium (3H)Liquid Scintillation Counters

Photomultiplier Tubes

Electronic Noise

3H

14C

32P

log Scale

isotopes tritium 3 h10
IsotopesTritium (3H)

Blank:

Prepare blank exactly as samples without activity

  • Radionuclide standard:
  • Amount of spike = expected activity in sample
  • Prepare exactly as all samples are prepared
  • Count exactly as samples are counted
  • CPM from spiked sample/DPM of spike = Efficiency in CPM/DPM
isotopes tritium 3 h11
IsotopesTritium (3H)

Dark adapt samples for a minimum of 30 minutes:

(Light interacts with sample usually causing the first sample to appear hot)

Chemical interaction can cause spurious pulses (chemoluminescense) in the Tritium Window (first 3 or 4 channels)

How do I know if I have contamination?

Is my sample greater than my background upper control limit? If yes, then I am 99% confident that I have levels above background.

isotopes tritium 3 h12
IsotopesTritium (3H)
  • Suggestions:
  • Have the first carrier be anything that is counted for 30 minutes to dark adapt all of the samples.
  • Shake samples to reduce chemoluminescence and wipe off vials to reduce refraction of the light from oil on the vials from your fingers.
  • Have the second carrier contain a blank and a standard to use for the QA/QC.
  • If possible, have the LSC program subtract the background upper control limit and divide by the calculated efficiency.
isotopes tritium 3 h13
IsotopesTritium (3H)
  • Suggestions:
  • Be sure your scintillation fluid is made to work with the sample that is to be counted (high pH/low pH, high aqueous load, high color, etc.)
  • Never count solid samples. Always digest them first.
  • Use teflon vials for high precision/low level counting. Tritium atoms can be absorbed into the plastic of plastic vials. Borosilicate vials will not absorb tritium either but they have a higher background.
questions select the best answer below using the mouse
QUESTIONS(Select the best answer below using the mouse)

What is the Annual limit of Intake (the activity that will yield a 5 Rem dose over the period of 1 year)?

A. 80 mCi

B. 800 mCi

C. 8.0 mCi

D. 80 mCi

slide15
CORRECT

The Annual limit of intake via ingestion or inhalation is 80 mCi. (this means that a total burden in the body from the stomach or lungs alone of 80 mCi will give a 5 Rem dose).

questions select the best answer below using the mouse16
QUESTIONS(Select the best answer below using the mouse)

Which Protective equipment is NOT required?

A Lab Coat

B Properly selected glove

C Protective Eyewear

D Shielding

slide17
CORRECT

Due to the low energy of the 3H beta particles, shielding is NOT required

questions select the best answer below using the mouse18
QUESTIONS(Select the best answer below using the mouse)

The Following is prohibited in isotope laboratories

A. Eating

B. Drinking

C. Smoking

D. All of the above

slide19
CORRECT

This should be obvious!!!!!

questions select the best answer below using the mouse20
QUESTIONS(Select the best answer below using the mouse)

What instrument do you employ to when checking for tritium contamination ?

A. Liquid Scintillation Counter

B. Geiger Counter

C. Gamma Counter

D. HPLC

slide21
CORRECT

The Geiger Counter and gamma counter will not detect the low energy tritium betas or any bremstrahlung radiation.

documenting training
DOCUMENTING TRAINING

Please sign and date the training form and click on the letter that indicates the first letter of your last name (ie. Farina is A)

A. A - F

B. G - L

C. M - R

D. S - Z

slide23
Questions ???

If you have any questions while reading the Radiation Safety Procedures

Please Feel Free to Contact:

The Radiation Safety Office

University Research Support and Administration

Office of Research Integrity

Georgia State University

Ground Floor

Alumni Hall

Atlanta, Georgia 30303

413-3540

slide24
INCORRECT

PLEASE TRY AGAIN

Return to question

slide25
INCORRECT

PLEASE TRY AGAIN

Return to question

slide26
CORRECT

BUT

PLEASE TRY AGAIN

There is a better answer!

Return to question

slide31
INCORRECT

PLEASE TRY AGAIN

Return to question

ad