A simple apparatus for preparing modest quantities of isotopically pure 4He

✍ Scribed by F.E Moss; A.F.G Wyatt; M.J Baird

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 333 KB
• Volume: 21
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(81)90060-6

✦ Synopsis

Recently, a number of experiments have been reported which have required isotopically pure 4 He.l The design of a sophisticated purifier, capable of producing litre quantities of pure 4 He in a single run, and resulting in 3 He concentrations which are likely to be < 10 -is has been presented by McClintock. 2 We present here a much simpler design which can be assembled in a few weeks, requires no special technology or materials, and results in 4 He which is likely to be of comparable purity. Our helium has been spectroscopically analysed 3 and found to contain less than 1 part in 1011 of 3 He, that being the limiting resolution. The apparatus produces pure helium at a rate of only "~ 10 cm h -~ ; a rate, however, which is satisfactory for most laboratory requirements. We shall show that this rate could, in principle, be increased significantly without any sacrifice in purity.