Table of Contents
Extraction (top) and injection (bottom).
The figure above depicts the setup. Group DDS system generate H=1 clock signals of which the phase is measured at Phase Measurement TR (PM). The values are transferred to the CBU, where matching is achieved. Then, the CBU broadcasts a trigger message via the timing network. Dedicated TR vor Kick and Diagnostics (KD) trigger the kicker electronics. Signals from the kicker electronics and kicker magnet probe are timestamped for further processing. From the hardware point of view, all components in the above figure are standard components (only the comparator is a custom build).
At present SCUs (Arria II FPGA) only provide 8ns granularity and slow I/Os, the hardware for PM, CBU and KD are TR in form-factor PCIe (Arria V FPGA) that provides 1ns timing granularity with I/Os supporting LVTTL signals with risetime/falltime below 1ns into 50 Ohm. The TR are mounted in 1U servers. No special FPGA gateware is used. All TRs use the regular gateware of the current release
of the timing system. The regular gateware includes a LM32 softcore in HDL that allows users to run firmware (C code) in hard real time on the FPGA. An example for such firmware is the 'function generator' for ramping magnets or RF systems. The 'glue' that converts the TR into modules for B2B is a dedicated firmware that is loaded into the LM32 at run-time.
Simplified sketch of White Rabbit Network (gray) and BuTiS clock distribution (coral) relevant for the B2B system at SIS18 and ESR. The figure shows the location/relation of the Local Master Switches
(LM), Data Master
(gold), White Rabbit Grandmaster Switch
(pink), B2B nodes (light green) and group DDS (dark green). Nodes that may send messages to the timing network are marked by hexagons. The connecting black arrows indicate the direction of clock propagation. The flow of data might be bi-directional.
The figure above shows a simplified sketch of the White Rabbit und BuTiS clock distribution networks. The nodes relevant for the B2B system are shown in light green, Central B2B Unit (CBU), Phase Measurement (PM) and Kicker trigger and Diagnostics (KD) for the two rings SIS18 und ESR. More detailed information is given on an internal page
Kicker and Diagnostics
Kicker signals and diagnostics. The figure on the oscilloscope screen show the following signals: Trigger from B2B (yellow), output from ACO electronics (blue), kicker magnet probe (magenta) and kicker magnet probe obtained via a capacitive voltage divider (green). Details see text.
The Bunch-2-Bucket system sends a timing message with CMD_B2B_TRIGGEREXT (not shown) to the Timing Receiver (TR) mounted in a 1U server. On-time, the TR creates a LVTTL signal (yellow) that is fed into a first set of electronics modules (this signal replaces the one from the famous 'Timing Generator'). The electronics performs certain tasks including the generation of a TTL signal (blue) that is fed into the main kicker electronics. When this happens, the kicker ignites and the kicker magnet is energized. A pickup probe allows to monitor the magnetic field at the kicker magnet. The probe signal is split and feeds various customers (magenta). The special feature of importance here is a capacitive voltage divider. A fast comparator is used to convert the output of the voltage divider signal to LVTTL (green). The bunch-2-bucket system uses the rising edges of signals for various purposes.
- electronics out
- signal is active: confirmation the electronics is supplied with settings data and the kicker is active
- monitoring of the set-value of the delay that has been set for the kicker
- probe signal
- signal is active: indication, that the full kicker scenario is working
- monitoring of the real kick time
vielleicht ein paar Bilder ...
- 04 Dec 2020