TEX (TEst stand for X-band) at LNF

TEX facility if commissioned for high power testing to characterize accelerating structures and validate them for the operation on future particle accelerators for medical, industrial and research applications. At this aim, TEX is directly involved in the LNF leading project EuPRAXIA@SPARC_Lab. The brief description of the facility and its status and prospective will be provided.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

DESIGN, FABRICATION AND HIGH POWER RF TEST OF A C-BAND ACCELERATING STRUCTURE FOR FEASIBILITY STUDY OF THE SPARC PHOTO-INJECTOR ENERGY UPGRADE

Abstract The energy upgrade of the SPARC photo-injector from 160 to more than 260 MeV will be done by replacing a low gradient 3m S-Band structure with two 1.4m high gradient C-band structures. The structures are travelling wave, constant impedance sections, have symmetric waveguide input couplers and have been optimized to work with a SLED RF input pulse. A prototype with a reduced number of cells has been fabricated and tested at high power in KEK (Japan) giving very good performances in terms of breakdown rates ( m bpp / 10 6 ) at high accelerating gradient (>50 MV/m). The paper illustrates the design criteria of the structures, the fabrication procedure and the high power RF test results

The C-Band accelerating structures for SPARC photoinjector energy upgrade

n/

Design, optimization and experimental characterization of RF injectors for high brightness electron beams and plasma acceleration

In this article, we share our experience related to the new photo-injector commissioning at the SPARC\_LAB test facility. The new photo-injector was installed into an existing machine and our goal was not only to improve the final beam parameters themselves but to improve the machine handling in day-to-day operations as well. Thus, besides the pure beam characterization, this article contains information about the improvements, that were introduced into the new photo-injector design from the machine maintenance point of view, and the benefits, that we gained by using the new technique to assemble the gun itself

Erratum to: EuPRAXIA Conceptual Design Report – Eur. Phys. J. Special Topics 229, 3675-4284 (2020), https://doi.org/10.1140/epjst/e2020-000127-8

International audienceThe online version of the original article can be found at http://https://doi.org/10.1140/epjst/e2020-000127-8</A

High power test results of the SPARC C-band accelerating structures

The energy upgrade of the SPARC photo-injector at LNF-INFN (Italy) from 180 to more than 240 MeV will be carried out by replacing a low gradient S-Band accelerating structure with two C-band structures. The structures are Traveling Wave (TW) and Constant Impedance (CI), with symmetric axial input couplers and have been optimized to work with a SLED RF input pulse. In this paper we present the results of the low and high power RF tests on the two fabricated structures that shown the feasibility of the operation at accelerating gradients larger than 35 MV/m

Nano-machining, surface analysis and emittance measurements of a copper photocathode at SPARC_LAB

R&D activity on Cu photocathodes is under development at the SPARC_LAB test facility to fully characterize each stage of the photocathode ‘‘life’’ and to have a complete overview of the photoemission properties in high brightness photo-injectors. The nano(n)-machining process presented here consists in diamond milling, and blowing with dry nitrogen. This procedure reduces the roughness of the cathode surface and prevents surface contamination introduced by other techniques, such as polishing with diamond paste or the machining with oil. Both high roughness and surface contamination cause an increase of intrinsic emittance and consequently a reduction of the overall electron beam brightness. To quantify these effects, we have characterized the photocathode surface in terms of roughness measurement, and morphology and chemical composition analysis by means of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscopy (AFM) techniques. The effects of -machining on the electron beam quality have been also investigated through emittance measurements before and after the surface processing technique. Finally, we present preliminary emittance studies of yttrium thin film on Cu photocathode