Graduate Studies in Accelerator Physics

28° Cycle Graduate Students

ROBERTO SALEMME

Thesis supervisor: Prof. Palumbo - Dipartimento di Scienze di base ed applicate per l'Ingegneria

Thesis title: Space Charge Compensation and Electron Cloud Eff ects in Modern High Intensity Proton Accelerators

Background

As Accelerator System Engineer, Roberto Salemme is currently involved in the international project Multi-purpose hYbrid Research Reactor for High-tech Applications. MYRRHA is an experimental research project proposed by SCK•CEN to demonstrate the feasibility and operability of a safe and efficient Accelerator Driven System (ADS) for transmuting long-lived radioactive waste. The MYRRHA driver is a Continuous Wave (CW) superconducting proton linac, characterized by an outstanding feature of reliability quantified by its tight design requirement of 250hrs as Mean Time Between Failures (MTBF). While the ongoing EURATOM FP7 MYRRHA Accelerator eXperiment (MAX) project’s goal is to deliver an updated consolidated conceptual design of the superconducting linac, with strong provisions for enhanced reliability, RFQ@UCL is a R&D program devoted to the Injector section engineering design and subsequent construction, followed by extensive testing and feedback to design. The principal motivation of RFQ@UCL is to experimentally address the MYRRHA injector design, gaining experience from a tangible prototype. The initial experimental test stand is constituted by a commercial 30 keV ECR proton source followed by a Low Energy Beam Transport (LEBT) section, injecting a matched beam into the 4-rod RFQ. This test stand is meant both to experimentally investigate a number of beam-related critical issues and to validate technological choices in this accelerator part. These include: the CW operability of the 4-rod RFQ and the Space Charge Compensation (SCC) phenomenon in the LEBT, the adoption of interceptive and non-interceptive diagnostic devices for high intensity CW beams, the design and exploitation of a high power, modular, 176.1 MHz Solid State RF amplifier, the development of a robust and comprehensive control system, based on innate propensity to fault-tolerance and predictive intelligence.

Brief report of scientific activity performed during 2013

In 2013, Roberto took technical leadership of RFQ@UCL, contributing to the establishment of its first infrastructure and participating to the commissioning of the proton source, a 30 keV ECR Ion Source characterized by high proton beam current output (20mA) with low emittance (0.1π∙mm∙mrad RMS norm. @5mA). In collaboration with LPSC Grenoble, Roberto contributed to the design of the Low Energy Beam Transport line as well as to the concept design of the RFQ interface, a section hosting the LEBT Beam Chopper, the RFQ collimator, the Electron Repeller System and the Beam Current Transformer. Lately in 2013, the development of the LEBT Control System infrastructure kicked off. Those activities were accompanied by participation to specific training schools (Technologies and Applications of Particle Accelerators, Joint Universities Accelerator School (JUAS); MYRRHA Accelerator eXperiment (MAX) School), sectorial conference and workshops (Technology and Components of Accelerator-Driven Systems (TCADS2), Second International Workshop, OECD Nuclear Energy Agency; AccApp 2013, Eleventh International Topical Meeting on Nuclear Applications of Accelerators, SLHiPP-3, 3rd Open Collaboration Meeting on Superconducting Linacs for High Power Proton Beams), collaboration meetings and Design Reviews (MYRRHA Accelerator eXperiment (MAX) 5th and 6th general meeting, MYRRHA Low Energy Beam Transport (LEBT) Control System kick-off meeting, MYRRHA Low Energy Beam Transport (LEBT) 1st and 2nd Design Review).

PhD thesis: Space Charge Compensation and Electron Cloud Effects in Modern High Intensity Proton Accelerators

Publications