Production and trapping of radioactive atoms at the TRIμP facility

Abstract

The structures for the TRIµP facility have been completed and commissioned. At the facility radioactive nuclides are produced to study fundamental interactions and symmetries. An important feature is the possibility to trap radioactive atoms in order to obtain and hold a pure substrate-free sample for precision measurements. In the TRIµP facility a production target is followed by a magnetic separator, where radioactive isotopes are produced in inverse reaction kinematics. Separation up to 99.95% could be achieved for 21 Na. A novel transmitting thermal ionizing device was developed to stop the energetic isotopes. Some 50% of stopped 21 Na could be extracted and transported as low energy singly charged ions into a radio frequency quadrupole cooler and buncher with 35% transmission efficiency. The ions are transported lossless via a drift tube and a low energy electrostatic beam line into the experimental setup. Such ions can be neutralized on hot metal foils and the resulting atoms can be stored in a magneto-optical trap. The functioning of that principle was demonstrated with stable Na extracted from the thermal ionizer, radioactive beams will follow next.

Laser spectroscopy of trapped short-lived Ra+ions

“…Rates of 800 212 Ra + /s, 2600 213 Ra + /s, and 1000 214 Ra + /s were extracted as an ion beam with an energy of 2.8 keV. The Ra + isotopes were passed through a Wien Filter (which eliminated contaminants from the TI), and electrostatically decelerated upon injection in a (N 2 or Ne) gasfilled Radio Frequency Quadrupole (RFQ) cooler [25], operated at a frequency of 500 kHz with a peak-to-peak RF voltage of V RF = 380 V applied between neighboring rods; the opposite half-moon-shaped electrodes had a tip distance of 5 mm. For on-line optical spectroscopy, the ions were trapped at the end of the RFQ by suitable axial potentials (Paul trap); cf.…”

Production of short lived radioactive beams of radium

“…Therefore, the production method used for Ra can be exploited for other actinides as well. For completeness we also note that we transported the produced isotopes successfully through a RFQ cooler and buncher [1]. The current yields are more than sufficient to start our experimental program concerning parity violation and EDM searches.…”

Atomic parity violation in a single trapped radium ion

“…The Ra + isotopes were passed through a Wien Filter (which eliminated contaminants from the TI), and electrostatically decelerated upon injection in a (N 2 or Ne) gas-filled Radio Frequency Quadrupole (RFQ) cooler [31], operated at a frequency of 500 kHz with a peak-to-peak RF voltage of V RF = 380 V applied between neighboring rods; the opposite half-moon-shaped electrodes, 10 mm Fig. 4).…”