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| Master Thesis | GSI-2023-00663 |
;
2023
Forschungszentrum
Jülich
Abstract: For decades, metastable hydrogen atoms have already been produced in one of the two 2S_1/2 α states using a spin-filter. Since 2001, this has also been commonpractice in the Institute for Nuclear Physics at the Research Center in Jülich. Therefore, a combination of a magnetic and an electric field as well as a radiofrequency are used to energetically separate the states and dependent on the strength of the used magnetic field, it is possible to choose one state which surviveswhile the others get deexcited into the ground state. By comparing the measured intensities of photons from the Lyman-α transitions of both 2S_1/2 αstates which are produced by quenching the surviving state with an electric field into the ground state, the polarisation of the beam can be observed.Unfortunately, for an ongoing experiment at the Technical University of Munich it is also necessary to measure the occupation numbers of 2S_1/2 β3 state ofthe hydrogen atom, which is not possible with the original spin-filter.The first concept was to exchange the occupation numbers of the α1 and β3 state with a Sona transition unit, but it faild due to additional transitions induced by the sinusoidal magnetic field of the transition unit. The second idea was a concept of a new type of spin-filter. Unlike the original one, this spin-filter should have a rectangular cavity instead of a round one,which should provide two radio frequencies. Those should make the electric field of the original spin-filter unnecessary. Combined with a magnetic field toenergetically separate the hyperfine states, this spin-filter should be able to filter all four 2S_1/2 states of hydrogen individually and independently. But due toa lower lifetime of the 2P_1/2 e states which are necessary for the filtering process because of the missing electric field, the intensities of the filtered states weretoo low, which made this concept not suitable enough for the use in Munich.Therefore, the third attempt for filtering the 2S1/2 β3 state was the production of a new Medium Field Transition Unit based on concepts of already existingones. In distinction to those transition units, this one should work for metastable atoms instead of ground state ones. Therefore, the existing designswere modified for this case of application. This transition unit should consist of a vacuum chamber with a coil for a radio frequency which should providethe energy for the necessary transitions from the 2S_1/2 β3 state into one of the 2S_1/2 α states which could then be measured by the spin-filter. This chambershould be surrounded by a perpendicular magnetic gradient and holding field. After the production and successful tests of the magnetic fields and theresonance spectrum of the coil for the radio frequency, the transition unit was installed inside the experimental setup right between two of the original spinfilter.After testing the influence of the transition unit on the beam for different beam configurations, it was discovered that the transition unit can be used as atransversal Sona transition if the radio frequency is shut off. Unfortunately, the transition unit could not be tested for its original purpose, but the discoveredbehaviour will make this device very helpful for various other experiments.
Note: NOCH AP
Note: Masterarbeit, RWTH Aachen University , 2023
Contributing Institute(s): Research Program(s): Experiment(s):
Appears in the scientific report 2023
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