Libera LLRF

Benefits:

• proven high performance LLRF solutions tailored to your needs
• high level of RF field stabilization based on temperature control technology (amplitude stability < 0.01% RMS, phase stability <0.01 deg RMS)
• high reliability: compact LLRF solutions in a robust 19″ MTCA modular platform (MTBF ~ 100 years)
• life-cycle support: commissioning assistance, training, maintenance, upgrades
• ease of use: out-of-the-box functional through GUI, ready to be integrated into Control System (EPICS ready)

Data processing:

Libera LLRF, the industrial digital RF stabilization system, offers a unique combination of hardware, real-time digital signal processing and software. The system continuously tracks the RF system signals and applies a feedback RF signals to it.

In the figure below, a possible configuration of Libera LLRF is presented. Libera LLRF tracks the cavity voltage (probe) signal and according to it applies a control drive signal to the cavity through the RF system power amplifiers. Further diagnostics on directional coupler forward and reflected signals enable Libera LLRF to measure cavity resonant frequency and therefore act on the cavity tuning system through stepper-motors or other equivalent tuning devices.

Some Libera LLRF features:

• operation modes support: pulse, CW
• control type: intra-pulse feed-back, pulse-by-pulse feedback, beam loading compensation (based on separate amplitude and phase controllers)
• different RF system controller topology support (1 by 1, 1 to many)
• cavity tuning based of directional coupler diagnostics or cavity decay signal analysis, supported on different interfaces (ETH, USB, Modbus)
• RF system diagnostics on multiple signals
• Fast interlock system (Machine protection)
• Temperature stabilized design
• RF system conditioning capabilities

Interfaces:

• fits into a 19 inch industrial rack
• 8 or up to 32 RF inputs for one RF output
• 2U height
• integrated power supply: 12 V DC
• mechanical structure of the chassis: up to eight application specific Advanced Mezzanine Cards (AMCs) connected via integrated backplane
• all interface connectors at the front
• cooling by two hot-swap replaceable fan modules on both sides of the chassis

1. CPU module:

Implements functions of the µTCA Carrier Hub (MCH) with interfaces: 2x PCIe, 2x LXI, JTAG, RS-232, DVI, management USB, management ETH, USB and 2x ETH. A fast PCIe bus is used for the data transfer between COM Express module and AMC application boards. This solution supports the implementation of low-latency control algorithms, real-time data processing and dedicated RF system diagnostics tools.

2. ADC9 module:

Double width mid-size AMC modules can process up to 8 RF inputs. The Libera LLRF system is configurable and can host from one to maximum four such modules. A Libera LLRF receiver module includes a calibration system and a LO distribution. The FPGA mounted on the board is used for hardware control and digital signal processing.

3. Vector modulator module:

Single width mid-size AMC module with two RF inputs and two RF outputs. The two inputs can be used in feedback. One of the two RF outputs is used for the drive signal generation. The FPGA mounted on the board is used for hardware control and digital signal processing.

4. Timing module:

Single width mid-size AMC module. Generates a low jitter local oscillator (LO) signal and a suitable sampling clock for the down-conversion and acquisition processes.

Provide the possibility to add additional features to the Libera LLRF system.

The Libera LLRF system architecture is based on PCIe implemented on AMC standards. It is a user-friendly network-attached device that has a powerful computational interconnect board (ICB) managing a number of satellite boards.