The Saphir Gas-Jet and a First Application to an On-Line Separation of Niobium

Abstract

A gas-jet system is described which has been installed at one of the external beam lines of the reactor SAPHIR. By means of a Boral chopper between the target chamber and beam line timed production of fission products can be achieved. In a first experiment this gas-jet system was used to develop a continuous and fast separation for short-lived isotopes of niobium with half-lives down to 7 s using isothermal gas chromatography in quartz columns. As reactive gas HBr^j was used.

Gas chemical investigation of hafnium and zirconium complexes with hexafluoroacetylacetone using preseparated short-lived radioisotopes

“…Recently, element 112 was investigated in a gas phase chemistry experiment in its elemental state [3]. Single atoms of these elements were either transported to a chemistry setup with a gas-jet, i.e., attached to aerosol particles that are suspended in rapidly flowing carrier gas [4][5][6][7][8] or as volatile species after thermalization in a gas mixture containing the reactive component [9,10]. Element 112 was transported in its volatile elemental state [3].…”

“…M(hfa) 4 (M = Zr, Hf) are well known complexes [48] and have been investigated with respect to their usefulness as precursors for thin oxide film production of these metals [48]. Zr(hfa) 4 is thermally stable (unlike Zr(tfa) 4 and Zr(acac) 4 [49]) and often employed in gas chromatography studies [50].…”

“…M(hfa) 4 (M = Zr, Hf) are well known complexes [48] and have been investigated with respect to their usefulness as precursors for thin oxide film production of these metals [48]. Zr(hfa) 4 is thermally stable (unlike Zr(tfa) 4 and Zr(acac) 4 [49]) and often employed in gas chromatography studies [50]. The M(hfa) 4 complexes of Zr and Hf are also very similar in other chemical properties [48]: i) both are moisture sensitive, ii) they cannot be separated by gas chromatography owing to their very similar volatility, iii) thermogravimetric analysis (TGA) experiments gave indications for partial decomposition at 146-147…”

“…We therefore investigated the gas-phase formation of M(hfa) 4 (M = Zr, Hf) with respect to their potential for investigating Rf in the same chemical system. Using Hf radioisotopes with half-lives between some tens of seconds and several minutes allowed for the determination of the reaction time as a function of the reaction temperature, which was done over a large temperature range.…”

“…The beam intensity was about 1.1 × 10 11 s −1 . The nuclear reaction products were preseparated in the BGS and Hf was converted to the volatile Hf(hfa) 4 complexes which were transported to an ACC trap installed outside of the irradiation cave. Five parallel irradiations were performed.…”