much thorium showing up? DR. THOMPSON: Well, the thorium, I believe, should be taken out, as I understand it, in the washing of the resin columns with hydrochloric acid. We can probably get rid of that by increasing that wash. of the procedure you should probably ask Phil Krey. For the details It's his procedure. At any rate, it only moderately interferes with what we are doing. OR. WRENN: We do the same sorts of analyses in my tab and we use solvent extraction as opposed to ion exchange and our impression is that we don't have thorium interference. 10 il DR. THOMPSON: the HCl wash. | I think we could get rid of the thorium by increasing At least this is what my chemist tells me. 12 CHAIRMAN MOSELEY: Other questions? 13 MR. KREY: Phil Krey from EML. To answer Ed's question, Roger is cor- 14 rect in that the hydrochloric acid wash of the second column is the exact 15 step which remains thorium. 16 explained it, and have in our laboratory completely eliminated any thorium 17 contribution so there is some little communication gap we have here. 18 other point is you saw a polonium peak on the spectrum which doesn't inter- 19 fere with that and shouldn't really be there either and after you electro- 20 plate, if the platinum disk is heated correctly, you will vaporize any of 21 the polonium and that will be removed also so you should, as you indicate, 22 come up with a clean spectrum. 23 slight contamination by thorium or polonium, it may not interfere with the 24 analysis but from a purist's sense, it would be neater and should be com- 25 pletely clean. We have looked into the problem, as Roger has Roger is also correct that if there is some | 26 CHAIRMAN MOSELEY: 27 This brings us to an early lunch according to my schedule. 28 The Any further questions? reconvene at 1:15 p.m. back here. 166 Thank you very much. We will