OLGA-II, AN ONLINE GAS CHEMISTRY APPARATUS FOR APPLICATIONS IN HEAVY ELEMENT RESEARCH

OLGA II is a device which performs on-line gas phase separations of volatile compounds of atoms produced in nuclear reactions. Reaction products are attached to aerosol particles and transported in a gas-jet to a heated quartz column and stopped in a quartz wool plug kept at 900 to 1000-degrees-C. Volatile compounds are formed by the addition of reactive gases. The volatile compounds are transported along a cooler, isothermal part of the column by the gas flow. The retention time in the isothermal part of the column is related to the enthalpies of adsorption of the compounds on the quartz surface. Separated atoms leaving the column are attached to new aerosol particles and transported through a second gas-jet to a detection system. This apparatus consists of a modified tape system. In a first collecting chamber the products are deposited on the surface of a stepwise moving tape. At preset times the deposited activity is moved past a series of six counting chambers equipped with charged particle or high-purity germanium detectors for alpha, spontaneous-fission, X- and gamma-ray counting. Data acquisition is performed event-by-event which allows to detect also correlated events. The system can be used for nuclides with half-lives longer than about 10 s. Correlated events can be resolved for times greater-than-or-equal-to 150-mu-s between consecutive decays.