Abstract
The SuperKEKB injector linac that includes the positron damping ring (DR) delivers low emittance electron and positron beams to the main rings. The beam injection phase from linac to the rings should be stabilized for long-term stable beam injection. The frequencies of the linac master oscillator (MO) and ring MO are 571.2 and 508.9 MHz, respectively. These two different frequency signals are monitored using the direct sampling technique with a common sampling rate. A phase drift of several degrees is observed between the linac and ring MOs. For stable beam injection, a phase drift compensation system is implemented at linac. The system performance was evaluated by the beam energy stability after the bunch compression system from DR to linac.
Highlights
The SuperKEKB [1] is a double-ring collider that consists of a high energy ring (HER) of 7 GeV electron, and a low energy ring (LER) of 4 GeV positron
The linac MO (LMO) and ring MO (RMO) signals are digitized by analog-to-digital converter (ADC) with a 124.63 MHz sampling rate, and in-phase and quadrature (IQ) components are obtained by digital down conversion (DDC)
The LMO (571.2 MHz) and RMO (508.9 MHz) signals are monitored by the direct sampling technique with a common sampling rate
Summary
The SuperKEKB [1] is a double-ring collider that consists of a high energy ring (HER) of 7 GeV electron, and a low energy ring (LER) of 4 GeV positron. The injector linac, DR, and MR have their own independent master oscillators (MO) that belong to the commercial Agilent E8663 series [3] They are synchronized with a 10 MHz trigger generated by the main MO (MMO) signal of 510 MHz by dividing with 51. A phase drift of several degrees is observed between the two MOs by the phase monitor [3] This MO phase drift significantly affected the beam energy stability after the BCS cavity in RTL because of a five times larger phase for 2856 MHz. the beam injection phase tuning from linac to the MR had to be conducted frequently, since beam injection background has been a critical problem for the SuperKEKB Belle II detector [7]. The phase stability between LMO and RMO is required less than Æ0.1° (peak to peak) at 571.2 MHz
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
