Daniele Sertore

High QE photocathodes performance during operation at FLASH / PITZ photoinjectors

Since 1998, the DESY photoinjectors at FLASH and PITZ routinely use high quantum efficiency (QE) photocathodes produced at LASA (INFN-Milano). To further understand the photocathode behavior during beam operation, photocathode QE measurements have been performed at different operating conditions in both photoinjectors. The analysis of these measurements will be used to improve the photocathode preparation procedures and deepen our understanding of the photocathode properties. An important goal is to further increase their lifetime and to preserve a high beam quality during the operation in the RF gun of the photoinjector.

High pressure rinsing system comparison

High pressure rinsing (HPR) is a key process for the surface preparation of high field superconducting cavities. A portable apparatus for the water jet characterization, based on the transferred momentum between the water jet and a load cell, has been used in different laboratories. This apparatus allows collecting quantitative parameters that characterize the HPR water jet. In this paper, we present a quantitative comparison of the different water jets produced by various nozzles routinely used in different laboratories for the HPR process.

First energy spectra obtained with a time-of-flight (TOF) electron spectrometer on Cs/sub 2/Te photocathodes

The first electron energy spectra obtained from a Cs/sub 2/Te photocathode using a time-of-flight (TOF) spectrometer are presented and discussed in this paper. The high-resolution angle resolved TOF electron spectrometer has been developed at INFN Milano-LASA (theoretical resolution: 2 meV at 5 eV). The system has been designed for the investigation of the electron beam thermal emittance that is a key parameter for future generation FEL based high brilliance photon sources. The excitation light source is a short pulse solid-state Nd:glass laser (4/sup th/ harmonic, /spl tau/=400 fs, /spl lambda/=264 nm). In this paper the spectrometer is presented together with first measurements on different metals and Cs/sub 2/Te.

NON-LINEARITY OBSERVED IN THE DIRECT SUB-PS PHOTOEMISSION REGIME IN MO

The total charge emitted from a polycrystalline Mo surface by 500 fs-264 nm laser pulses has been measured. Though a one-photon photoelectric effect is expected, a non-linear increase of the photoelectric yield was observed as a function of laser peak intensity, confirming earlier observations on Au, W and Zr. The threshold intensity for this non-linearity is 2 between 0.1 and 0.2 GW/ cm . The linear and non-linear regimes were clearly discerned in the experimental data. The non-equilibrium heating of the conduction electrons is considered as the cause of the observed non-linear behaviour.

ESS Superconducting RF Collaboration

The European Spallation Source (ESS) project is a neutron-scattering facility, currently under construction by a partnership of at least 17 European countries, with Sweden and Denmark as host nations. The ESS was designated a European Research Infrastructure Consortium, or ERIC, by the European Commission in October of 2015. Scientists and engineers from 50 different countries are members of the workforce in Lund who participate in the design and construction of the European Spallation Source. In complement to the local workforce, the superconducting RF linear accelerator is being prototyped and will be constructed based on a collaboration with European institutions: CEA-Saclay, CNRS-IPN Orsay, INFN-LASA, STFC-Daresbury, Uppsala and Lund Universities. After a description of the ESS collaborative project and its in-kind model for the SRF linac, this article will introduce the linac component first results.

Update on Third Harmonic XFEL Activities at INFN LASA

After the successful installation and beam operation of the first batch of 3.9 GHz cavities into the XFEL Third Harmonic Injector Module, ten more cavities have been tested and delivered to DESY to be assembled into a spare cryomodule. In this paper, we report on the activities related to the cavities fabrication, treatment and vertical testing at INFN LASA.

Compton scattering techniques for the measurement of the transverse beam size of particle beams at future linear colliders

21st Beam Dynamics Workshop on Laser-Beam Interactions, State University of New York, Stony Brook, NY, USA, 11 Jun 2001 - 15 Jun 2001; 6 pp. (2001).