BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:A discharge plasma source for proton-driven plasma wakefield accel eration at CERN DTSTART:20260317T140000Z DTEND:20260317T160000Z DTSTAMP:20260627T160424Z UID:07f471c7-71f5-422a-b540-788260fd04ee SEQUENCE:3 CREATED:20260225T103524Z DESCRIPTION:This thesis presents the development\, characterisation\, and first beam operation of a Discharge Plasma Source (DPS) designed for the A WAKE proton-driven plasma-wakefield acceleration experiment at CERN. The s ystem\, first proposed by Instituto Superior Técnico (Lisbon) and Imperia l College London as a scalable technology\, was assembled at CERN to be co mpatible with both laboratory studies and beamline operation\, combining f lexibility for development with the operational robustness required in the CERN accelerator complex. The thesis primarily describes the plasma diagn ostics implemented to characterise the discharge properties. Interferometr y was employed to measure the temporal evolution of the axially averaged e lectron density. Discharges in xenon\, argon\, and helium were studied\, y ielding peak plasma densities up to (1.78±0.15)\, (0.97±0.06)\, and (0.3 6±0.02)x1015cm-3 respectively\, for discharge currents up to 500 A in 10 m plasma tubes of 13 mm radius. Complementary Thomson-scattering measureme nts provided local electron density and temperature\, confirming axial uni formity within ±6 % at peak density\, close to the diagnostic current pre cision. The DPS was subsequently installed and operated in the AWAKE exper iment during a dedicated proton-beam run\, where it operated reliably duri ng a three-week campaign. The proton bunch underwent self-modulation in pl asmas produced by the DPS\, representing the first demonstration of a disc harge-based plasma technology in AWAKE. Experiments with different plasma lengths indicated the concept’s potential for scalability\, while the us e of multiple gases enabled the study of ion-motion effects in the proton self-modulation instability. Overall\, the work demonstrates that the DPS can generate long and reproducible plasmas suitable for plasma-based accel eration experiments. The results establish a solid experimental foundation for the future development of modular\, extended plasmas capable of incre asing the acceleration length in AWAKE or in other plasma-based accelerato r projects. LAST-MODIFIED:20260227T112833Z LOCATION:Online URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/a-discharge-plasma-source- for-proton-driven-plasma-wakefield-acceleration-at-cern/ X-ALT-DESC;FMTTYPE=text/html:

This thesis present s the development\, characterisation\, and first beam operation of a Disch arge Plasma Source (DPS) designed for the AWAKE proton-driven plasma-wakef ield acceleration experiment at CERN. The system\, first proposed by Insti tuto Superior Técnico (Lisbon) and Imperial College London as a scalable technology\, was assembled at CERN to be compatible with both laboratory s tudies and beamline operation\, combining flexibility for development with the operational robustness required in the CERN accelerator complex.

The thesis primarily describes the plasma diagnostics implemented to characterise the discharge properties. Interferometry was employed to mea sure the temporal evolution of the axially averaged electron density. Disc harges in xenon\, argon\, and helium were studied\, yielding peak plasma d ensities up to (1.78±0.15)\, (0.97±0.06)\, and (0.36±0.02)x1015cm-3 res pectively\, for discharge currents up to 500 A in 10 m plasma tubes of 13 mm radius.

Complementary Thomson-scattering measurements provide d local electron density and temperature\, confirming axial uniformity wit hin ±6 % at peak density\, close to the diagnostic current precision. The DPS was subsequently installed and operated in the AWAKE experiment durin g a dedicated proton-beam run\, where it operated reliably during a three- week campaign. The proton bunch underwent self-modulation in plasmas produ ced by the DPS\, representing the first demonstration of a discharge-based plasma technology in AWAKE.

Experiments with different plasma l engths indicated the concept’s potential for scalability\, while the use of multiple gases enabled the study of ion-motion effects in the proton s elf-modulation instability. Overall\, the work demonstrates that the DPS c an generate long and reproducible plasmas suitable for plasma-based accele ration experiments. The results establish a solid experimental foundation for the future development of modular\, extended plasmas capable of increa sing the acceleration length in AWAKE or in other plasma-based accelerator projects.

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