Fast, high precision, low cost position diagnostic for free electron lasers

Lead Research Organisation: Royal Holloway University of London
Department Name: Physics

Abstract

Beam instrumentation are the eyes and ears of an operator delivering an electron beam to a free electron laser (FEL). In particular, position diagnostics help optimising and later reproducing the "golden" path for electrons throughout the FEL that ensures the best quality and brightest burst of X-ray light at the FEL's output. It is important to sustain the best possible conditions for experiments making use of the X-rays, which can include a wide variety of investigations, in subjects ranging from archeology to bio-science, from security to nanofabrication.

It is a never ending quest for scientists and engineers designing FELs and driving them linear accelerators (linacs) delivering the electrons for lasing, to provide better performance at a lower cost. Inevitably, new ideas are in demand. Our project is part of this quest: we have an idea on how to replace older beam position diagnostics with a newer, higher resolution, faster type without inflating the cost. This new idea is waveguide beam position monitors (WGBPM).

WGBPM models have demonstrated their basic functionality in our laboratory, but significant effort is still needed to convert this work into a demonstrator prototype that can be installed in a real life electron accelerator. Therefore, we will focus on developing the hardware and methods for a real life proof-of-principle experiment. This will involve multiple 3D electromagnetic simulations to optimise the device and predict its output, work with mechanical engineers to ensure the device can be easily manufactured and all the complex demands of an accelerator machine are met.

The signals produced by WGBPMs are very short electric pulses, which will need to be turned into useful information. We will design analogue electronics which will help preparing these pulses for crossing the boundary between the analogue and digital worlds and also work on algorithms that extract the position information from the digitised signals.

We are then hoping to proceed to a critical test, installing the prototype in a real life accelerator exposing it to a beam of electrons. We want to see that the device can indeed sense the beam's position the way it is supposed to, and confirm our expectations on the output it gives and the precision it can sense the beam position with.

By the end of this project we would like to be able to start "knowledge exchange": team up with a company and work towards making waveguide beam position monitors available to scientists worldwide in a form of a complete, commercially available product.

Publications

10 25 50
 
Description This award facilitated the development of an innovative Beam Position Monitor (BPM) that utilises waveguides to detect the electromagnetic fields surrounding a particle beam. This novel design integrates a built-in feature to mitigate strong sum signals and extract the differences, enabling more precise measurements. The project entailed a comprehensive design study that validated the anticipated fundamental characteristics, including high position sensitivity, linearity of response versus beam displacement, and suppression of the sum signal. Based on this study, a prototype design was developed and had progressed to the initial stages of hardware prototyping. Subsequent steps involve finalising the hardware design and conducting beam tests to assess the monitor's performance under real-world conditions. This design holds promise for significantly improving the accuracy and reliability of beam positioning measurements at a reduced cost, with potential applications spanning research and applied particle accelerators.

This award helped us developing an innovative beam position monitor (BPM) that incorporates waveguides to detect the electromagnetic fields enveloping a particle beam. This new design includes a built-in capability to mitigate strong sum signals and isolate the differences for more precise measurements. The project included a comprehensive design study that demonstrated the expected fundamental characteristics such as the high position sensitivity, linearity of the response vs beam displacement and suppression of the sum signal. The study resulted in a ptototype design, which went into first stages of hardware prototyping. The next steps involve finalizing the hardware design and conducting beam tests to evaluate the monitor's performance in real-world conditions. This novel design promises to enhance the accuracy and reliability of beam positioning measurements, with potential applications in research and applied particle accelerators.
Exploitation Route The technology developed for beam position measurements in this project holds significant promise for future linear colliders and light sources, particularly those utilising very short bunches, such as plasma-generated beams. This innovative approach offers measurement capabilities comparable to more costly monitor types while also providing a substantially higher measurement bandwidth. The design, while requiring precision machining, is straightforward, rendering it commercially viable. Moreover, it can be readily scaled for implementation in various facilities, including medical accelerators, thereby expanding its potential applications. Additionally, the design minimises negative wake effects on the beam, further enhancing its utility and effectiveness.
Sectors Electronics

Energy

 
Description This project has unexpectedly expanded into various impact areas, particularly in the realm of radio-frequency (RF) electronics. It has catalysed a range of initiatives aimed at commercialising components of the system, which hold broader research and industrial implications. Key focus areas include the development of high-precision compact RF sources, showcasing potential applications in fields such as communications, space technology, and quantum computing. Additionally, there has been a surge of interest in RF printed circuit board (PCB) manufacturing, offering opportunities for both internal and external PCB design and manufacturing services. These endeavors not only foster innovation but also serve as valuable training platforms for motivated young undergraduate and postgraduate researchers and engineers, thereby nurturing the future workforce in this dynamic field.
First Year Of Impact 2024
Sector Education,Electronics
Impact Types Societal

Economic

 
Description International Exchanges 2021 Cost Share (JSPS) - Dynamic compensation method in high precision electron beam position measurements
Amount £11,800 (GBP)
Funding ID IEC\R3\213050 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2022 
End 03/2025
 
Description Remote controlled precision radio frequency source
Amount £45,000 (GBP)
Organisation Royal Holloway, University of London 
Sector Academic/University
Country United Kingdom
Start 08/2021 
End 12/2024
 
Title RF and microwave electronics prototyping facilities 
Description The Accelerator Laboratory at RHUL has been upgraded with rapid prototyping capabilities. This is enabled by using the modular system supplied by XMicrowave. Tools and skills required to work with this system have been developed in addition to the existing measurement equipment covering up to 20 GHz. The system allows us to quickly test ideas minimizing the development time and cost. First results have also been obtained with the desktop PCB isolation milling machine recently installed in the Accelerator Laboratory. This is currently limited to low-frequency electronics but allows us to learn the methods and acquire skills required to operate CNC mills in anticipation that a professional-grade mill suitable for RF&Microwave applications will become available through STFC Equipment grants. 
Type Of Material Improvements to research infrastructure 
Year Produced 2022 
Provided To Others? Yes  
Impact Quick prototyping of RF and microwave electronics. PCB prototyping for low-frequency electronics. 
 
Description Collaboration between RHUL and ATF2/KEK (Japan) 
Organisation KEK
Country Japan 
Sector Academic/University 
PI Contribution The collaboration between RHUL and Accelerator Test Facility 2 (KEK, Japan) is currently being renewed. This collaboration will concentrate on developments vital to a successful long-term operation of beam diagnostics in a future linear collider. It will include planning upgrades towards a new ATF3 facility. A travel grant to facilitate this collaboration has been awarded by The Royal Society. RHUL will contribute fresh ideas on improving long-term monitoring and stability of microwave diagnostics.
Collaborator Contribution KEK will contribute the hardware required for prototyping. It will also contribute beam time at the unique ATF2 facility for testing.
Impact Joint exchange grant application, awarded to the UK team.
Start Year 2021
 
Description Collaboration between RHUL and INFN (italy) 
Organisation National Institute for Nuclear Physics
Department Frascati Laboratory (LNF)
Country Italy 
Sector Public 
PI Contribution LNF and RHUL started collaborating on developing and testing signal processing algorithms for precision beam position measurements. In the framework of this collaboration, RHUL provides methods and algorithms for digital signal processing and machine learning.
Collaborator Contribution INFN/LNF provides experimental data for testing the processing algorithms which have been obtained with a test setup of 3 high resolution cavity beam position monitors installed in a precision beamline at one of the INFN's test beam facilities.
Impact Ongoing work, no output yes
Start Year 2022
 
Description Collaboration with an EU high-tech electronics company 
Organisation Instrumentation Technologies
Country Slovenia 
Sector Private 
PI Contribution RHUL conducted an informal review of iTech's proposal for ELI-NP (Romania) contractual work. RHUL and iTech collaborate on cavity beam position system development for ELI-BL (LUIS, Czech Republic)., CLARA (Daresbury Laboratory, UK) and CLEAR (CERN, Switzerland). There is an established stream of ideas going both ways.
Collaborator Contribution Instrumentation Technologies hold regular meetings with RHUL which facilitate RHUL developments and benefit the impact of RHUL work. iTech also contributed hardware for a cavity beam position experiment at CERN. A number of potential joint developments are currently in discussion.
Impact iTech delivered several data acquisition and control systems for CLARA (Daresbury Laboratory, UK). Together with another RHUL partner, FMB-Oxford, iTech bid for and won a contract to deliver processing and data acquisition electronics for ELI-BL (LUIS, Czech Republic).
Start Year 2016