JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Li, Z. AU - Bernal, E. AU - Hartford, J. AU - Ikegami, M. ED - Schaa, Volker RW ED - Götz, Andy ED - Venter, Johan ED - White, Karen ED - Robichon, Marie ED - Rowland, Vivienne TI - FRIB Beam Power Ramp Process Checker at Chopper Monitor J2 - Proc. of ICALEPCS2023, Cape Town, South Africa, 09-13 October 2023 CY - Cape Town, South Africa T2 - International Conference on Accelerator and Large Experimental Physics Control Systems T3 - 19 LA - english AB - Chopper in the low energy beam line is a key ele-ment to control beam power in FRIB. As appropriate functioning of chopper is critical for machine protec-tion for FRIB, an FPGA-based chopper monitoring system was developed to monitor the beam gated pulse at logic level, deflection high voltage level, and in-duced charge/discharge current levels, and shut off beam promptly at detection of a deviation outside tolerance. Once FRIB beam power reaches a certain level, a cold start beam ramp mode in which the pulse repetition frequency and pulse width are linearly ramped up becomes required to mitigate heat shock to the target at beam restart. Chopper also needs to gen-erate a notch in every machine cycle of 10 ms that is used for beam diagnostics. To overcome the challeng-es of monitoring such a ramping process and meeting the response time requirement of shutting off beam, two types of process checkers, namely, monitoring at the pulse level and monitoring at the machine cycle level, have been implemented. A pulse look ahead algorithm to calculate the expected range of frequency dips and rises was developed, and a simplified mathe-matical model suitable for multiple ramp stages was built to calculate expected time parameters of accumu-lated pulse on time within a given machine cycle. Both will be discussed in detail in this paper, followed by simulation results with FPGA test bench and actual instrument test results with the beam ramp process. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1256 EP - 1260 KW - diagnostics KW - target KW - controls KW - FPGA KW - monitoring DA - 2024/02 PY - 2024 SN - 2226-0358 SN - 978-3-95450-238-7 DO - doi:10.18429/JACoW-ICALEPCS2023-THMBCMO26 UR - https://jacow.org/icalepcs2023/papers/thmbcmo26.pdf ER -