Photocathodes for Accelerator Science in Europe (PhASE 2026)
In the framework of the series of the european workshops on photocathodes for particle accelerator applications (previousy EWPAA), the next event will be held in France, near Paris, following the 5th edition hosted at HZDR in Dresden in 2024.
Organized by CNRS/IN2P3 via LPSC and IJCLab, the Photocathodes for Accelerator Science in Europe workshop (PhASE26) will be hosted by Irène Joliot Curie Laboratory (IJCLab) in Orsay, September 21-23, 2026. This meeting brings together experts in the field of photocathode electron sources dedicated to particle accelerators aiming to share knowledge and latest progress in this field, critical of future accelerators.
The in-person event will propose about 40 oral presentations, organized in 8 sessions, as well as a poster session (format A0, portrait) and visits of IJCLab’s infrastructures.
The sessions will cover:
- overview of photocathode research
- accelerator applications of photocathodes
- photocathode related studies and novel concepts
- metallic photocathodes
- semiconductor photocathodes
- polarized photocathodes
- theory of photocathodes
- characterization techniques.
A social event is planned with a diner cruise on the Seine river, allowing sight seeing of beautiful Paris monuments (Notre Dame, Eiffel tower, Louvre).
Proceedings will be published (no peer-review) based on one-page summary provided by each speaker when the workshop starts.
If you need a visa to attend this event, please contact the organizers.
We hope to see you in Orsay !
Important deadline:
Registration deadline : July 27, 2026
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Registration
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Opening sessionPrésident de session: Maud BAYLAC (CNRS)
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Welcome by IJCLab director and overview of IJCLab activties 35mOrateur: Prof. Achille Stocchi
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Overview of photocathode research: OverviewPrésident de session: Maud BAYLAC (CNRS)
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Coffee break 30m
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Lunch at the university cafeteria
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Photocathodes for accelerator applicationsPrésident de session: Eduardo Granados
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R&D with the sealab gun 20mOrateur: Jonas Dube
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R&D for CLARA 20mOrateur: Hugh Churn
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Cesium Telluride Photocathodes for the European XFEL and FLASH 20mOrateur: Anna Winiarska-Bialk
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Coffee break 30m
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16:20
UED sources for ultra fast applications 20mOrateur: Charles Zhang
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16:40
Electron source development and charge scaling at FACET-II 20mOrateur: Brendan O'Shea
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Tutorial: Photocathode physics, a band structure perspective
Photocathode Physics: A Band Structure Perspective
In this tutorial, after a brief historical introduction, the key components associated with our understanding of photocathode physics will be presented with particular emphasis on the properties of the bulk electronic states from which the photo-excited electrons are emitted. The photoemission physics of both metals and semiconductors will be discussed with attention to two emission mechanisms: (i) transverse momentum conserving direct photoemission from the occupied band states [1] and (ii) momentum and energy resonant Franck-Condon emission involving inelastic scattering processes – electron-(optical)phonon scattering in semiconductors [2] and Umklapp electron scattering in metals [3]. In all cases, the energetic position and dispersion of the emitting bulk band states have a direct influence on the quantum efficiency (QE) and mean transverse energy (MTE) of electron emission. Both the QE and MTE are also strongly dependent upon the temperature Te of the electron distribution in those states, which is generally not equal to the lattice temperature of the photocathode.
Throughout the presentation, direct comparison will be made to experimental measurements of the QE and MTE to demonstrate the connection between the bulk band structure of photocathodes and their photo-excited electron emission properties. In particular, spectral measurements of the photoemission properties of single-crystal metal photocathodes will be shown to be consistent with band-based emission simulations that include the density of states of both the emitting band and recipient vacuum states [4]. Further, the influence of upper conduction bands will be discussed with reference to experimental data obtained from a Cu(111) photocathode [5], while a comparison of the near and below threshold emission properties of Cu(001) and W(111) photocathodes elucidates the effect of Umklapp electron scattering [3]. For semiconductor photocathodes, a Franck-Condon emission mechanism mediated by electron-(optical)phonon scattering usually dominates and the QE and MTE are dependent on both Te and the position of the bottom of the emitting band with respect to the vacuum level (i.e., its electron affinity) – even if the principal emission is from an upper conduction band – in agreement with measurements on cesiated p-type GaAs(001) and p-type GaN(0001) photocathodes [2]. Experimental evidence for additional direct band emission observed from the primary, low effective mass, conduction band of a 300K Fe-doped Ga2O3(010) photocathode, generating a sub-thermal MTE, is also consistent with the expected temperature of the photo-excited electron distribution [6].
[1] W.A. Schroeder and G. Adhikari, New J. Phys. 21, 033040 (2019).
[2] W.A. Schroeder, L.A. Angeloni, I-J. Shan, and L.B. Jones, Phys. Rev. Applied 23, 054065 (2025).
[3] I-J. Shan, L.A. Angeloni, and W.A. Schroeder, https://arxiv.org/abs/2604.12979
[4] G. Adhikari, P. Riley, and W.A. Schroeder, AIP Advances 9, 065305 (2019).
[5] L.A. Angeloni, I-J. Shan, and W.A. Schroeder, AIP Advances 12, 105129 (2022)
[6] L.A. Angeloni, I-J. Shan, J.H. Leach, and W.A. Schroeder, J. Appl. Phys. 139, 095706 (2026).Président de session: Andreas Schroder -
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Posters
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Photocathode related studiesPrésident de session: Lee Jones
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Electron beam from laser-cooled atoms: latest developments at Eindhoven 20mOrateur: Julius Huijts
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Ultrafast Electron Diffraction Sources and Photocathode R&D at Tsinghua University 20mOrateur: Renkai Li
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Compact all optical terahertz (THz)-driven electron source 20mOrateur: Nicolas Matlis
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Field emission and plasmon-assisted photocathodes: from field-emitter arrays and single emitters to graphene-edge cathodes 20mOrateur: Soichiro Tsujino
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Coffee break 30m
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Metallic and semiconductor photocathodesPrésident de session: Rong Xiang (HZDR)
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Cryogenically cooled copper photocathode for SRF gun 20mOrateur: Dmitry Bazyl
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Electron emission at metallic needle tips and nanophotonic electron accelerators 20mOrateur: Manuel Konrad
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Semiconductor photocathodes feedback and towards FCCee 20mOrateur: Giulia Tenasini
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Soft- and hard XPS and XAS measurements on a Na-K-Sb photocathode 20mOrateur: Alice Galdi
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Photocathode developments for Brixsino 20mOrateur: Daniele Sertore
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Lunch at the university cafeteria
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Semiconductor photocathodesPrésident de session: Julius Kuehn
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Photocathode developments at SLAC 20mOrateur: Theo Vecchione
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Semiconductor photocathodes: Modeling electron emission processes 20mOrateur: Andreas Schroder
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Coffee break 30m
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Polarized photocathodesPrésident de session: Daniele Sertore (INFN Milano - LASA)
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High polarization photocathodes at Mainz 20mOrateur: Kurt Aulenbacher
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Enhanced GaAs activation using Li and recent developments towards automated activation 20mOrateur: Markus Engart
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Operating and Innovating a Polarized Electron Source 20mOrateur: Joe Grames
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High polarization high QE photocathodes for EIC 20mOrateur: Erdong Wang
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Trip to Paris (RER/metro) and diner cruise on Seine river
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Photocathode theoryPrésident de session: Andreas Schroeder
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Photoemission simulation from nanostructured surfaces 20mOrateur: Margarita Bulgacheva
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Collective and surface charge effect for high brightness e bunch production for FCC 20mOrateur: Anahita Omoumi
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Coffee break 30m
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Characterization techniquesPrésident de session: Tim Noakes
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Characterization of lifetime of bi alkali photocathodes 20mOrateur: Saransh Malhotra
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Photocathodes transfer for suitcase purposes 20mOrateur: Cyril Straessle
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Closing session
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Lunch at the university cafeteria
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Lab tour
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Visit of IJCLab facilities 2h
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Coffee break 30m
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