The Design, Construction, and Testing of a Knudsen Effusion Mass Spectrometric System Suitable for Studies of Nuclear Fuel Materials

Abstract

Benefiting hugely from many years of experience of conducting vaporization studies with a commercially bought magnetic sector instrument (VG Micromass 30 BK), we designed and constructed a KEMS system having a quadrupole mass spectrometer. It essentially consisted of two chambers, one housing the Knudsen cell furnace assembly and the other housing the QMS with an indigenously designed and fabricated vacuum-isolation valve between these two chambers. The QMS initially used was from Extrel, but later that from Hiden was installed. Systematic vaporization experiments were undertaken on iron, nickel, chromium, zirconium, a Fe-Al alloy, MnO, uranium, and a U-Zr alloy. Electron bombardment heating was employed and the temperatures were measured by sighting the optical pyrometer onto a blackbody hole drilled at the bottom of the Knudsen cell. The results on the elements and the Fe-Al alloy were satisfactory while those on MnO, U, and U-Zr alloy were disconcerting but interesting and educative.