Difference between revisions of "KJM5911 Lab Exercise 4 - Szilard-Chalmers Reaction and Liquid-Scintillation Counting"

From mn/safe/nukwik
Jump to: navigation, search
(Theory)
Line 17: Line 17:
  
 
=== Experimental Procedure  ===
 
=== Experimental Procedure  ===
 +
 +
You will get n-activated ethyliodide from your supervisor. The 128I half-life is only 25 min, so make sure you are well prepared and that you know exatly what you should do. Practice the complete procedure with "cold" reagents before starting to work with the radioactive material!
 +
 +
#Use an automatic pipette to transfer 1 mL of the n-irradiated ethyliodide to a counting vial.
 +
#Transfer 2 mL&nbsp;ethyliodide to a test tube containing 2 mL&nbsp;NaHSO<sub>3</sub> solution. The test tube must have a cap and be able to withstand centrifugation.
 +
#Shake the test tube violently for 60 s.
 +
#Transfer 1 mL&nbsp;of each phase to counting vials.
 +
#Count the three counting vials on a NaI well-crystal. Count long enough to ensure that the counting uncertainty is less than 5%.
 +
#Calculate the count rate (in cps or cpm) and correct for background.
 +
#Correct for decay and calculate:
 +
 +
*the retention (amount in the organic phase) and the yield of the carrier free radioactivity in the inorganic phase.
  
 
=== Reports  ===
 
=== Reports  ===

Revision as of 15:17, 14 November 2012

UnderConstruction pict22.gifUnderConstruction pict17.gif

Learning Goals

After this exercise, you should know about and understand the following topics:

  • The difference between radioactivity with or without carrier.
  • Szilard-Chalmers method to produce carrier-free radioactive halides.

Theory

Experimental Procedure

You will get n-activated ethyliodide from your supervisor. The 128I half-life is only 25 min, so make sure you are well prepared and that you know exatly what you should do. Practice the complete procedure with "cold" reagents before starting to work with the radioactive material!

  1. Use an automatic pipette to transfer 1 mL of the n-irradiated ethyliodide to a counting vial.
  2. Transfer 2 mL ethyliodide to a test tube containing 2 mL NaHSO3 solution. The test tube must have a cap and be able to withstand centrifugation.
  3. Shake the test tube violently for 60 s.
  4. Transfer 1 mL of each phase to counting vials.
  5. Count the three counting vials on a NaI well-crystal. Count long enough to ensure that the counting uncertainty is less than 5%.
  6. Calculate the count rate (in cps or cpm) and correct for background.
  7. Correct for decay and calculate:
  • the retention (amount in the organic phase) and the yield of the carrier free radioactivity in the inorganic phase.

Reports

Safety Aspects