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Paul Scherrer Institut

Laboratory of Radiochemistry and Environmental Chemistry

Uni Bern
Paul Scherrer Institute, Department of Biology and Chemistry
University of Bern, Department of Chemistry and Biochemistry
CH-5232 Villigen PSI
Freiestr. 3, CH-3012 Bern
Tel +41 (0)56 310 24 01
Tel +41 (0)31 631 42 42



Updated:
08.01.2010
E-Mail: thorsten.bartels-rausch@psi.ch


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Tools and Instrumentation

Heavy Elements research group (Group Leader: Robert Eichler)

The Cryo On-Line Detector (COLD)
Isotopes of transactinide elements suitable for their chemical investigation are produced on a one-atom-at-a-time scale in heavy ion induced nuclear fusion reactions. Hence, the experiments are carried out at the following accelerator facilities: the PSI Philips Cyclotron Villigen, Switzerland (shutdown end 2007), the UNILAC GSI Darmstadt, Germany, the 88" Cyclotron LBNL Berkeley, USA , and the U-400 FLNR Dubna, Russia, the RIKEN Accelerator, the JAEA Tandem Accelerator, and the Lanzhou Accelerator facility. The time scale for producing one atom of the heaviest elements reaches from minutes (261Rf) to days (283112).

The experiments employ gas jet techniques coupled to the On-Line Gas Chromatography Apparatus OLGA and recently, for the study of very volatile elements and compounds the In-situ Volatilization and On-line detection IVO system. The chemical separation has to be very efficient and selective.
The developed detection systems must have the capabilities to measure life times and decay energies of alpha, beta and gamma-decaying and spontaneous fissioning nuclides. These requirements are fulfilled by sophisticated detection techniques: the PSI Tape System (PTS), the ROtating wheel Multidetector Analyzer ROMA and recently the Cryo-On-Line Detector (COLD).
Model experiments are carried out in order to test the efficiency and velocity of developed chemical procedures. Therefore, the PSI Philips cyclotron and the 252Cf fission source “Miss Piggy” at Bern University (Miss Piggy) are used to produce short-lived nuclides of elements, which are expected to behave homologous to the transactinides.
The experiments and the interpretation of the results are supported by thermodynamic calculations of the stabilities, volatilities, and transport processes as well as by Monte Carlo simulations of the gas chromatographic process of single atoms.

More Pictures

The Cryo-On-Line Detector (COLD)


The Cryo On-Line Detektor (COLD)

 


The open COLD

 


The cooling finger and the detection channel

 


The open detection channel. One side is coated alternatively with gold or platinum, the other side consists of 32 Pin Diodes

 


Close up of the Pin Diodes

 


One single Pin Diode. Size compared to a match.

 

The 252-Cf fission source “Miss Piggy”

 

The 252-Cf fission source "Miss Piggy"