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FIZIKA B 12 (2003) 2, 135 - 144
 
RADIOACTIVE CHARGE CARRIERS IN LIQUID HELIUM CREATED FROM FAST NUCLEAR
BEAMS
NORIAKI TAKAHASHI
Osaka Gakuin University, Kishibe-Minami 2-36-1, Suita/Osaka, 564-8511
Japan
Received 10 March 2003; revised manuscript received 26 June 2003
Accepted 28 July 2003 Online 3 March 2004
An ionic positive charge in superfluid helium exists in the form of an aggregate of
helium atoms around a core ion and is called a "snowball". Positively charged
impurities were created through injection of fast nuclear beams into liquid helium. The
transport of positive charges in liquid helium was traced through the measurements of
electric currents and of radioactive decays of the impurity ions. Applied electric fields
of both directions controlled the movements of impurity ions unambiguously. Production
rates of snowballs and of neutrals from the injection of nuclear beams have been
estimated. The rates change differently for various ions used, not only with temperature
of the liquid helium but also with spatial density of the incident fast beams.
PACS numbers: 67.40.Jg, 36.40.Wa
UDC 531.746, 535.547
Keywords: snowballs, radiation detection method, radioactive nuclear beams, liquid 4He
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