The ISOLTRAP spectrometer installed at ISOLDE/CERN

Experimental setup Up to recently, ISOLTRAP consisted of three parts: a radio-frequency quadrupole (RFQ) ion trap for beam preparation and two Penning traps. The linear, gas-filled RFQ ion trap cools the 60 keV continuous ISOLDE beam via bu er gas cooling. Furthermore, the ions are accumulated and leave the so-called buncher as ion bunches towards the preparation Penning trap where contaminants are removed with a resolving power of up to 105. The ions are then transferred to the second, precision Penning trap for the mass measurement. Finally, the time-of-flight detection technique is employed to determine the frequency of an ion stored in a Penning trap, from which the mass can be extracted in conjunction with a reference mass measurement.
During the year 2010, a multi-reflection time-of-flight (MR-ToF) mass separator was installed and successfully commissioned. The MR-ToF mass separator acts as an auxiliary device for isobaric purification of rare-isotope ensembles, which not only conserves a high ion-of-interest throughput (in the case of strong contamination, but also works on shorter time scales than the preparation trap thus enhancing the capabilities of ISOLTRAP significantly.