Study of Lorentz force detuning and its compensation in …
Jan 1, 2021 · Lorentz force detuning is a major issue for superconducting cavities at higher voltage gradients of the accelerator. The focus of this paper is to review Lorentz force detuning and its behaviour in various superconducting cavities.
Lorentz Force Detuning Control • Timing, amplitude, width and bias level of the piezo drive signal are chosen to cancel the detuning due to Lorentz Force • Control algorithm • The measured response is used to automatically calculate an appropriate compensation waveform and adapt that waveform to changing cavity operating conditions
drive signal are chosen such that the detuning of the cavity by the resulting acoustic impulse cancels the detuning of the cavity induced by the Lorentz force. This technique can successfully reduce the detuning of the cavity during the RF pulse …
When the cavity is de-tuned, the steady state cavity voltage and the generator are out of phase. The detuning angle is found from Eqn. 39: Cavity Coupling for Superconducting Cavities coupler can be thought Vref, Iref of as a Vfor, transformer Ifor between the power source and the in …
Microphonics and Lorentz force detuning have a signifi-cant impact on the achievable field stability and rf power requirements in superconducting accelerators. The pulsed operation of high gradient cavities results in dynamic Lorentz force detuning approaching or exceeding the bandwidth of the cavity of the order of a few hundred Hz.
Lorentz force detuning values. The predicted SNS assembly stiffness of 1.1x10 5 lb/in (1.9x10 7N/m) was simulated and produced a K L of -3.6, exceeding the requirement of -3 Hz/(MV/m) 2. These calculations demonstrate the importance of the boundary conditions in determining the static Lorentz force detuning (see Fig. 5).
In virtue of the high pulse to pulse repeatability of the detuning, the compensation of Lorentz detuning was achieved successfully using a simple feed forward scheme. Lorentz forces in TESLA-type superconducting cavities operated in pulsed mode generate a time varying detuning which for typical accelerating gradients amounts in hundreds of Hz.
In this paper, is presented a new numerical model for a pillbox cavity that can predict the frequency shifts caused by the LFD and external pressure.
Study of Lorentz force detuning and its compensation in …
Jan 1, 2021 · This paper gives an insight into estimating the Lorentz force detuning, its consequences, and various techniques adopted to mitigate the LFD effect in the superconducting radiofrequency cavity in different accelerators.
For high gradient operation (over 15MV/m) the mechani- cal deformation of the cavity during the RF pulse should be compensated by piezo tuner. The paper presents design of a piezo control system and the results of measurements of its efÞciency.