Experimental+procedure+for+the+separation+of+234mPa+from+238U+and+measurement+of+its+half-life

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 * 1) You have been supplied with a boiling tube containing a preweighed amount of uranyl nitrate
 * 2) Measure out 100 cm 3 of deionised H 2 O and add enough of this to the boiling tube to dissolve the uranyl nitrate. Decant this into a conical flask and then add the remaining H 2 O.
 * 3) Pass all of this through the ion exchange column at a rate of 2-3 drops per second – the eluant should be colourless as the yellow metal ions (UO 2 2+ ) have been adsorbed onto the resin. **DO NOT let the ion exchange column run dry at any time. **
 * 4) Wash the column with 100 cm 3 of deionised water.
 * 5) Pass ~200 cm 3 of 2 M HCl through the column and collect the yellow eluant in a beaker – this will remove the 238 U and 234m Pa from the resin.
 * 6) Wash the column with deionised water until the eluant is colourless – collecting it in the same beaker as the acid soln
 * 7) Transfer this eluant to a bottle labelled **Uranyl residues **
 * 8) Wait 5 min for concentration of 234m Pa to build up on column
 * 9) Manwhile ask demonstrator to explain how the liquid Geiger counter works
 * 10) Pass ~200 cm 3 5 M HCl though the column, when the eluent is yellow run 100 cm 3 and into the liquid Geiger counter
 * 11) Place the cap on the counter and begin taking readings every 10 seconds.
 * 12) Continue until the counts decrease to background levels
 * 13) Wash the column with ~300 cm 3 of deionised water– leave enough water to cover the amberlite resin in the column
 * 14) A value can be obtained by plotting the log of the 234m Pa activity (corrected for background) against time. You should plot the graph, using Excel, over an activity range of an order of magnitude for accuracy, using 6 or 7 points. Remember to take off the background activity level

**Note**: The column still has 234 Th adsorbed on the resin. Thus, 234m Pa is continually being formed and could be removed at any time by passing more HCl through the column. It is therefore a source of 234m Pa as long as the 234 Th lasts. This is sometimes referred to as a 234m Pa cow (milked when wanted), a better name is a 234m Pa generator. Generators of this type are common. The basic requirement is for a moderately long-lived isotope, which decays to a shorter-lived isotope, which can then be chemically separated from the parent. One of the most widely used is the 99m Tc generator, from which it can be eluted from its 99 Mo parent, to be used for bone and liver scanning.