Abstract
The design of a 150 MHz λ/4, 3- and 4- gap structures with two and three loading elements, for the velocity range β = 0.015 - 0.12 has been accomplished. Rotary and displacement tuners are developed for
multi-stub superconducting RF resonators. The effectiveness of these tuners is made possible because the resonators have low currents between their outer conductors and tuner elements. Computer simulations
and experimental data show that the devices provide a tuning range up to 100 kHz with a frequency resolution of about 1 Hz. The manufacturing of the 150 MHz 2-QWR with rotary tuner has been completed. A credible design of 2-QWR and its rotary tuner have been developed and tested at room temperature. The PbSn plating, exercised on the existing split loop resonators, will be extended to the 2-QWR as a straightforward
step to quickly explore the superconducting performance of the new geometry. The commissioning of the plating equipment has been started. In the longer term, the Nb sputter coating will be researched because,
in principle, it can produce films competitive to the much more expensive solid niobium option and performs at higher fields than plated lead. The twelve split loop resonators have been electroplated with 96%Pb4%Sn film to the final thickness of 1.5 micron using methyl sulfonic acid chemistry achieving average acceleration field of 3.5 MV/m off-line. Measurement
of the non-linear surface impedance and intermodulation distortion (IMD) has been conducted on the full-scale split-loop resonators (SLR). IMD
measurements allow more sensitive detection of nonlinearity
as compared to surface impedance measurements. The source of the non-linearity in the resonator structure, such as magnetic flux penetration can be located by its contribution to the non-linear IMD response above a critical RF power level.
multi-stub superconducting RF resonators. The effectiveness of these tuners is made possible because the resonators have low currents between their outer conductors and tuner elements. Computer simulations
and experimental data show that the devices provide a tuning range up to 100 kHz with a frequency resolution of about 1 Hz. The manufacturing of the 150 MHz 2-QWR with rotary tuner has been completed. A credible design of 2-QWR and its rotary tuner have been developed and tested at room temperature. The PbSn plating, exercised on the existing split loop resonators, will be extended to the 2-QWR as a straightforward
step to quickly explore the superconducting performance of the new geometry. The commissioning of the plating equipment has been started. In the longer term, the Nb sputter coating will be researched because,
in principle, it can produce films competitive to the much more expensive solid niobium option and performs at higher fields than plated lead. The twelve split loop resonators have been electroplated with 96%Pb4%Sn film to the final thickness of 1.5 micron using methyl sulfonic acid chemistry achieving average acceleration field of 3.5 MV/m off-line. Measurement
of the non-linear surface impedance and intermodulation distortion (IMD) has been conducted on the full-scale split-loop resonators (SLR). IMD
measurements allow more sensitive detection of nonlinearity
as compared to surface impedance measurements. The source of the non-linearity in the resonator structure, such as magnetic flux penetration can be located by its contribution to the non-linear IMD response above a critical RF power level.
| Original language | English |
|---|---|
| Pages | TUP59 |
| Publication status | Published - 2008 |
| Event | 13th International Workshop on RF Superconductivity: SRF Workshop 2007 - Peking University, Beijing, China Duration: 14 Oct 2007 → 19 Oct 2007 https://accelconf.web.cern.ch/srf2007/INDEX.HTML |
Conference
| Conference | 13th International Workshop on RF Superconductivity |
|---|---|
| Country/Territory | China |
| City | Beijing |
| Period | 14/10/07 → 19/10/07 |
| Internet address |