Paper |
Title |
Page |
MOPOMS027 |
Synthesis of First Caesium Telluride Photocathode at ASTeC Using Sequential and Co-Deposition Method |
695 |
|
- R. Valizadeh, A.N. Hannah
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
- V.R. Dhanak
The University of Liverpool, Liverpool, United Kingdom
- S. Lederer
DESY, Hamburg, Germany
|
|
|
Caesium Telluride (Cs2Te) photocathodes, are the elec-tron source of choice, by many global accelerators such as European XFEL, FLASH and AWA. It offers high quantum efficiency and reasonable operational lifetime with lower vacuum requirements than multi-alkali photocathodes. In this paper, we report on the first synthesised CsxTe photocathodes at ASTeC, using both sequential and co-deposition of Te and Cs on Mo substrate. Te deposition is carried out using ion beam deposition whilst the Cs is deposited using a SAES getter alkali. The ion beam deposition of Te provides a high degree of control to give a dense, smooth layer with a reproducible film thickness. The chemical state with respect to film composition of the deposited CsxTe is determined with in-situ XPS anal-yses. The films exhibit a quantum efficiency between 7.5 to 9 % at 266 nm wavelength.
|
|
DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS027
|
|
About • |
Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022 |
Cite • |
reference for this paper using
※ BibTeX,
※ LaTeX,
※ Text/Word,
※ RIS,
※ EndNote (xml)
|
|
|
TUPOTK031 |
A First 6 GHz Cavity Deposition with B1 Superconducting Thin Film at ASTeC |
1279 |
|
- R. Valizadeh, A.N. Hannah, O.B. Malyshev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
- E. Chyhyrynets, V.A. Garcia Diaz, C. Pira
INFN/LNL, Legnaro (PD), Italy
- V.R. Dhanak
The University of Liverpool, Liverpool, United Kingdom
- O.B. Malyshev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
- G.B.G. Stenning
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
|
|
|
Nb3Sn, NbTiN and NbN are superconductors with critical temperatures of 18.3, 12.6-17 and 11.6-17.5 K, respectively, these are higher than that of Nb at 9.3 K. Hence, at 4 K, they have an RF resistance, an order of magnitude lower than that of Nb, which leads to quality factors above those of Nb. In recent years, there has been an extensive effort converting Nb cavities into Nb3Sn. Alloying the top inner layer of the cavity using Sn diffusion at a high temperature has had some degree of success, however, the reproducibility remains a major hindering and limiting factor. In this study, we report on the PVD deposition of NbTiN inside a 6 GHz cavity, using an external magnetic coil configuration. The deposition is done at an elevated temperature of about 650 C. We report on the superconducting properties, film structure and its stoichiometry and surface chemical state. The films have been characterised with SEM, XRD, XPS, EDS and SQUID magnetometer.
|
|
DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK031
|
|
About • |
Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022 |
Cite • |
reference for this paper using
※ BibTeX,
※ LaTeX,
※ Text/Word,
※ RIS,
※ EndNote (xml)
|
|
|
THPOTK036 |
Determination of Pumping and Dynamic Vacuum Properties of Conductive Quaternary Alloy of TiZrVAg Non-Evaporable Getter. |
2843 |
|
- R. Valizadeh, A.N. Hannah, O.B. Malyshev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
- G.Y. Hsiung
NSRRC, Hsinchu, Taiwan
- J.M. O’Callaghan Castella
Universitat Politécnica de Catalunya, Barcelona, Spain
- M. Pont, N.D. Tagdulang
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
|
|
|
Non Evaporable Getter (NEG) coating has been employed extensively in the particle accelerator especially where the vacuum conductance of the vessel is severely restricted and ultra-high vacuum condition is required. NEG coating will significantly reduce the outgassing rate and provides active pumping surface for H2, CO and CO2. In addition, it has been proven that NEG coated surfaces have a very low secondary electron yield, as well as low photon and electron stimulated desorption yields. However, the existing NEG film increases the RF surface resistance of the beam pipe. In order to increase NEG coating conductivity, at ASTeC, in the past several years, the alternative NEG com-position have been studied by adding more conductive element such as Cu, Au, Al and Ag. In this study, we report on the photon stimulated desorption, activation temperature and surface resistance from room temperature to cryogenic temperature for a new NEG quaternary alloy of TiVZrAg as function of the film composition.
|
|
DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK036
|
|
About • |
Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022 |
Cite • |
reference for this paper using
※ BibTeX,
※ LaTeX,
※ Text/Word,
※ RIS,
※ EndNote (xml)
|
|
|