First Beam through the FETS RFQ
26 May 2022
- Evan Jones



The Front End Test Stand (FETS) Project has successfully accelerated its first beam.

Team members celebrating the first beam through the FETS RFQ

​​Team members celebrating the first beam through the FETS RFQ


​As neutron science progresses so must the technology that helps enable it. The neutron sources of the future will need to be equipped with more powerful accelerators. A key part of an accelerator is its ‘Front end’. It is within this part of the accelerator that the first part of the acceleration process takes place. It is responsible for the initial production of the proton beam which goes on to become the source for neutrons and muons at ISIS.  

The Front End Test Stand (FETS) is a research and development project to build the front end of a linear accelerator that can be used for testing new techniques, physics and other components. This could eventually feed into larger experiments and contributes towards the development of future high power accelerators such as the ISIS-II facility upgrade project.  

The main component of FETS and the largest technical risk is the Radio Frequency Quadrupole (RFQ). The RFQ is a low energy accelerator designed to accelerate an H-minus ion beam to 3 MeV with high efficiency and beam quality. The FETS RFQ incorporates many innovative features, most notably it is able to be fully dismantled for easier inspection and repairs.  

Having commissioned the RFQ with full RF power last year, the first beam was successfully accelerated on Saturday 26th March 2022. This acceleration was primarily an opportunity to perform surveys to assess the radiation levels produced as well as to check the safety systems and procedures, a respectable 27 mA of H-minus ion current was accelerated.  

Following on from this achievement the team will move on with more routine operation to characterise the facility and tune the performance towards the design goals. 

Alan Letchford and the FETS RFQ Project

“FETS has been a long and at times frustrating project. To finally see everything working together and delivering beam was very satisfying and a huge relief. It is a testament to the years of world class effort by the staff at ISIS, RAL, STFC and our university and international partners.” – Alan Letchford 

Contact: Jones, Evan (STFC,RAL,ISIS)