234m-Pa+Radionuclide+Generator

Developed By
Tor Bjørnstad Section of Radiochemistry Institute of Chemistry Faculty of Mathematics and Natural sciences University of Oslo

Learning Goals
The task in this Laboratory Exercise is to record a disintegration curve of 234m Pa and from this curve determine the half-life of the nuclide. The 234m Pa radionuclide is obtained from a generator system consisting of an ion exchanger column with fixed 234 Th where the daughter is milked by a liquid elution process. The α particles from the produced 234m Pa-source is recorded by a GM-detector.
 * Understand mother-daughter relations and radioactive equilibrium
 * Understand how a radio-nuclide generator works and how it is used
 * Understand how radioactivity is "growing in"
 * Training in handling radioactive material and safety procedures

Theory
Principle Behind Mother-Daughter Relationship

Experimental Procedure
Production and Measurement of a 234mPa Nuclide Generator

Safety Aspects

 * Chemical safety - nothing particularly dangerous, 1 M HCl and 0.1 M AgNO 3 should of course be handled according to normal safety precautions. DOWEX residues and waste should be collected and handled according to normal procedures.
 * Rad. safety - very small amounts of uranyl nitrate is used, so rad. safety is mostly about regulations and not a real health hazard. Remember to collect the DOWEX from the ion-exchange columns in separate containers as it is contaminated with 24-day 234 Th (will be none-radioactive after one year).

Equipment
> K 4 [Fe(CN) 6 ] in 1 L water)
 * HCl [|(MSDS)] on 100 mL flasks, one for each student)
 * DOWEX 50x4 [| (MSDS)] (50-100 mesh)
 * Uranyl Nitrate [|(MSDS)] - UO 2 (NO 3 ) 2
 * NaAc [|(MSDS)] + K 4 [Fe(CN) 6 ]] ([|MSDS)] solution (on 100 mL flasks, one for each student) (prepared by mixing 8 g NaC 2 H 3 O 2 and 40 g
 * 10% [|citric acid (MSDS)] (on 100 mL flasks, one for each student)
 * 0.1 M [|AgNO3 (MSDS)] (on 50 mL flasks)
 * Suitable columns which can be fitted with a stopper connected to a rubber ball so it can be pressurized (to quickly elute drops with short lived 234 Pa from the column).*** Stop watches (one for each student)
 * Sample holders to catch eluted drops from the column and which can be mounted conveniently in the detector chamber
 * Detectors - GM counters works well, but we have also used plastic scintillators mounted on PMTs and NaI-detectors. High efficiency is necessary to get good counting statistics even after the first 5-6 minutes.

Preparation for the lab Supervisor
The equipment needed should be ready. The solutions needed should also be prepared. It is usually a good idea to not use to large columns as the time needed for the solution to pas trough the dowex will increase quite a lot with increased volume.

Feedback from Users and Supervisors
Please leave suggestions and feedback in the comments.