TY - CONF AU - Fisher, A.C. AU - Musumeci, P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Preliminary Study of a High Gain THz FEL in a Recirculating Cavity J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - The THz gap is a region of the electromagnetic spectrum where high average and peak power radiation sources are scarce while at the same time scientific and industrial applications are growing in demand. Free-electron laser coupling in a magnetic undulator is one of the best options for radiation generation in this frequency range, but slippage effects require the use of relatively long and low current electron bunches to drive the THz FEL, limiting amplification gain and output peak power. Here we use a circular waveguide in a 0.96 m strongly tapered helical undulator to match the radiation and e-beam velocities, allowing resonant energy extraction from an ultrashort 200 pC 5.5 MeV electron beam over an extended distance. E-beam energy measurements, supported by energy and spectral measurement of the THz FEL radiation, indicate an average energy efficiency of ~ 10%, with some particles losing > 20% of their initial kinetic energy. PB - JACoW Publishing CP - Geneva, Switzerland SP - 30 EP - 33 KW - electron KW - radiation KW - undulator KW - FEL KW - GUI DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOZD2 UR - https://jacow.org/napac2022/papers/mozd2.pdf ER - TY - CONF AU - Xu, T. AU - Carbajo, S. AU - Lemons, R.A. AU - Piot, P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Temporally-Shaped Ultraviolet Pulses for Tailored Bunch Generation at Argonne Wakefield Accelerator J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Photocathode laser shaping is an appealing technique to generate tailored electron bunches due to its versatility and simplicity. Most photocathodes require photon energies exceeding the nominal photon energy produced by the lasing medium. A common setup consists of an infrared (IR) laser system with nonlinear frequency conversion to the ultraviolet (UV). In this work, we present the numerical modeling of a temporal shaping technique capable of producing electron bunches with linearly-ramped current profiles for application to collinear wakefield accelerators. Specifically, we show that controlling higher-order dispersion terms associated with the IR pulse provides some control over the UV temporal shape. Beam dynamics simulation of an electron-bunch shaping experiment at the Argonne Wakefield Accelerator is presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 222 EP - 225 KW - electron KW - laser KW - controls KW - wakefield KW - cathode DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOPA78 UR - https://jacow.org/napac2022/papers/mopa78.pdf ER - TY - CONF AU - Kulkarni, A.V. AU - Denham, P.E. AU - Kogar, A. AU - Musumeci, P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Dual Radiofrequency Cavity Based Monochromatization for High Resolution Electron Energy Loss Spectroscopy J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Reducing the energy spread of electron beams can enable breakthrough advances in electron energy loss spectroscopic investigations of solid state samples where characteristic excitations typically have energy scales on the order of meV. In conventional electron sources the energy spread is limited by the emission process and typically on the order of a fraction of an eV. State-of-the-art energy resolution can only be achieved after significant losses in the monochromatization process. Here we propose to take advantage of photoemission from ultrashort laser pulses (~40 fs) so that after a longitudinal phase space manipulation that trades pulse duration for energy spread, the energy spread can be reduced by more than one order of magnitude. The scheme uses two RF cavities to accomplish this goal and can be implemented on a relatively short (~ 1m) beamline. Analytical predictions and results of 3D self consistent beam dynamics simulations are presented to support the findings. PB - JACoW Publishing CP - Geneva, Switzerland SP - 278 EP - 280 KW - cavity KW - electron KW - cathode KW - simulation KW - space-charge DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUXD6 UR - https://jacow.org/napac2022/papers/tuxd6.pdf ER - TY - CONF AU - Lewellen, J.W. AU - Filippetto, D. AU - Karkare, S.S. AU - Maxson, J.M. AU - Musumeci, P. AU - Smedley, J. AU - Vecchione, T. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - The Quest for the Perfect Cathode J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - The next generation of free electron lasers will be the first to see the performance of the laser strongly dependent on the materials properties of the photocathode. A new injector proposed for the LCLS-II HE is an example of this revolution, with the goal of increasing the photon energy achievable by LCLS-II to over 20 keV. We must now ask, what is the optimal cathode, temperature, and laser combination to enable this injector? There are many competing requirements. The cathode must be robust enough to operate in a superconducting injector, and must not cause contamination of the injector. It must achieve sufficient charge at high repetition rate, while minimizing the emittance. The wavelength chosen must minimize mean transverse energy while maintaining tolerable levels of multi-photon emission. The cathode must be capable of operating at high (~30 MV/m) gradient, which puts limits on both surface roughness and field emission. This presentation will discuss the trade space for such a cathode/laser combination, and detail a new collaborative program among a variety of institutions to investigate it. PB - JACoW Publishing CP - Geneva, Switzerland SP - 281 EP - 284 KW - cathode KW - gun KW - electron KW - emittance KW - photon DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUYD3 UR - https://jacow.org/napac2022/papers/tuyd3.pdf ER - TY - CONF AU - Denham, P.E. AU - Musumeci, P. AU - Ody, A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - X-Band Harmonic Longitudinal Phase Space Linearization at the PEGASUS Photoinjector J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Due to the finite bunch length, photoemitted electron beams sample RF-nonlinearities that lead to energy-time correlations along the bunch temporal profile. This is an important effect for all applications where the projected energy spread is important. In particular, for time-resolved single shot electron microscopy, it is critical to keep the beam energy spread below 1·10⁻⁴ to avoid chromatic aberrations in the lenses. Higher harmonic RF cavities can be used to compensate for the RF-induced longitudinal phase space nonlinearities. Start-to-end simulations suggest that this type of compensation can reduce energy spread to the 1·10⁻⁵ level. This work is an experimental study of x-band harmonic linearization of a beam longitudinal phase space at the PEGASUS facility, including developing high-resolution spectrometer diagnostics to verify the scheme. PB - JACoW Publishing CP - Geneva, Switzerland SP - 508 EP - 511 KW - cavity KW - linac KW - electron KW - gun KW - laser DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA77 UR - https://jacow.org/napac2022/papers/tupa77.pdf ER - TY - CONF AU - Lawler, G.E. AU - Bosco, F. AU - Fukasawa, A. AU - Li, Z. AU - Majernik, N. AU - Parsons, J.R. AU - Rosenzweig, J.B. AU - Sakai, Y. AU - Spataro, B. AU - Tantawi, S.G. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Cyborg Beamline Development Updates J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Xray free electron laser (XFEL) facilities in their current form are large, costly to maintain, and inaccessible due to their minimal supply and high demand. It is then advantageous to consider miniaturizing XFELs through a variety of means. We hope to increase beam brightness from the photoinjector via high gradient operation (>120 MV/m) and cryogenic temperature operation at the cathode (<77K). To this end we have designed and fabricated our new CrYogenic Brightness-Optimized Radiofrequency Gun (CYBGORG). The photogun is 0.5 cell so much less complicated than our eventual 1.6 cell photoinjector. It will serve as a prototype and test bed for cathode studies in a new cryogenic and very high gradient regime. We present here the fabricated structure, progress towards commissioning, and beamline simulations. PB - JACoW Publishing CP - Geneva, Switzerland SP - 512 EP - 515 KW - gun KW - cathode KW - cavity KW - cryogenics KW - simulation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA80 UR - https://jacow.org/napac2022/papers/tupa80.pdf ER - TY - CONF AU - Lawler, G.E. AU - Fukasawa, A. AU - Li, Z. AU - Mostacci, A. AU - Parsons, J.R. AU - Rosenzweig, J.B. AU - Simakov, E.I. AU - Spataro, B. AU - Tajima, T. AU - Tantawi, S.G. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Design of a High-Power RF Breakdown Test for a Cryocooled C-Band Copper Structure J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - High-gradient RF structures capable of maintaining gradients in excess of 250 MV/m are critical in several concepts for future electron accelerators. Concepts such as the ultra-compact free electron laser (UC-XFEL) and the Cool Copper Collider (C3) plan to obtain these gradients through the cryogenic operation (<77K) of normal conducting copper cavities. Breakdown rates, the most significant gradient limitation, are significantly reduced at these low temperatures, but the precise physics is complex and involves many interacting effects. High-power RF breakdown measurements at cryogenic temperatures are needed at the less explored C-band frequency (5.712 GHz), which is of great interest for the aforementioned concepts. On behalf of a large collaboration of UCLA, SLAC, LANL, and INFN, the first C-band cryogenic breakdown measurements will be made using a LANL RF test infrastructure. The 2-cell geometry designed for testing will be modifications of the distributed coupled reentrant design used to efficiently power the cells while staying below the limiting values of peak surface electric and magnetic fields. PB - JACoW Publishing CP - Geneva, Switzerland SP - 516 EP - 518 KW - cavity KW - cryogenics KW - GUI KW - distributed KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA81 UR - https://jacow.org/napac2022/papers/tupa81.pdf ER - TY - CONF AU - Lynn, W.J. AU - Andonian, G. AU - Doran, D.S. AU - Kim, S.Y. AU - Majernik, N. AU - OTool, S.M. AU - Piot, P. AU - Power, J.F. AU - Rosenzweig, J.B. AU - Wisniewski, E.E. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Transverse Stability in an Alternating Symmetry Planar Dielectric Wakefield Structure J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Dielectric Wakefield Acceleration (DWA) is a promising technique for realizing the next generation of linear colliders. It provides access to significantly higher accelerating gradients than traditional radio-frequency cavities. One impediment to realizing a DWA-powered accelerator is the issue of the transverse stability of the beams within the dielectric structure due to short-range wakefields. These short-range wakefields have a tendency to induce a phenomenon known as single-bunch beam breakup, which acts as its name implies and destroys the relevant beam. We attempt to solve this issue by leveraging the quadrupole mode excited in a planar dielectric structure and then alternating the orientation of said structure to turn an unstable system into a stable one. We examine this issue computationally to determine the limits of stability and based on those simulations describe a future experimental realization of this strategy. PB - JACoW Publishing CP - Geneva, Switzerland SP - 519 EP - 522 KW - wakefield KW - simulation KW - experiment KW - accelerating-gradient KW - quadrupole DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA82 UR - https://jacow.org/napac2022/papers/tupa82.pdf ER - TY - CONF AU - Majernik, N. AU - Andonian, G. AU - Lynn, W.J. AU - Piot, P. AU - Rosenzweig, J.B. AU - Xu, T. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Derivative-Free Optimization of Multipole Fits to Experimental Wakefield Data J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - A method to deduce the transverse self-wakefields acting on a beam, based only on screen images, is introduced. By employing derivative-free optimization, the relatively high-dimensional parameter space can be efficiently explored to determine the multipole components up to the desired order. This technique complements simulations, which are able to directly infer the wakefield composition. It is applied to representative simulation results as a benchmark and also applied to experimental data on skew wake observations from dielectric slab structures. PB - JACoW Publishing CP - Geneva, Switzerland SP - 523 EP - 526 KW - wakefield KW - simulation KW - multipole KW - experiment KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA83 UR - https://jacow.org/napac2022/papers/tupa83.pdf ER - TY - CONF AU - Zhang, S. AU - Apsimon, Ö. AU - Majernik, N. AU - Naranjo, B. AU - Rosenzweig, J.B. AU - Welsch, C.P. AU - Yadav, M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Reconstructing Beam Parameters from Betatron Radiation Through Machine Learning and Maximum Likelihood Estimation J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - The dense drive beam used in plasma wakefield acceleration generates a linear focusing force that causes electrons inside the witness beam to undergo betatron oscillations, giving rise to betatron radiation. Because information about the properties of the beam is encoded in the betatron radiation, measurements of the radiation such as those recorded by the UCLA-built Compton spectrometer can be used to reconstruct beam parameters. Two possible methods of extracting information about beam parameters from measurements of radiation are machine learning (ML), which is increasingly being implemented for different fields of beam diagnostics, and a statistical technique known as maximum likelihood estimation (MLE). We assess the ability of both machine learning and MLE methods to accurately extract beam parameters from measurements of betatron radiation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 527 EP - 530 KW - radiation KW - betatron KW - simulation KW - diagnostics KW - plasma DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA84 UR - https://jacow.org/napac2022/papers/tupa84.pdf ER - TY - CONF AU - Majernik, N. AU - Andonian, G. AU - Doran, D.S. AU - Kim, S.Y. AU - Lorch, C.D. AU - Lynn, W.J. AU - Piot, P. AU - Power, J.G. AU - Rosenzweig, J.B. AU - Whiteford, C. AU - Wisniewski, E.E. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - First Results from a Multileaf Collimator and Emittance Exchange Beamline J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - By shaping the transverse profile of a particle beam prior to an emittance exchange (EEX) beamline, drive and witness beams with variable current profiles and bunch spacing can be produced. Presently at AWA, this transverse shaping is accomplished with individually laser-cut tungsten masks, making the refinement of beam profiles a slow process. In contrast, a multileaf collimator (MLC) is a device that can selectively mask the profile of a beam using many independently actuated leaves. Since an MLC permits real-time adjustment of the beam shape, its use as a beam mask would permit much faster optimization in a manner highly synergistic with machine learning. Beam dynamics simulations have shown that such an approach is functionally equivalent to that offered by the laser cut masks. In this work, the construction and first results from a 40-leaf, UHV compatible MLC are discussed. PB - JACoW Publishing CP - Geneva, Switzerland SP - 531 EP - 534 KW - wakefield KW - plasma KW - acceleration KW - laser KW - vacuum DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA85 UR - https://jacow.org/napac2022/papers/tupa85.pdf ER - TY - CONF AU - Mann, J.I. AU - Arias, T. AU - Karkare, S.S. AU - Lawler, G.E. AU - Nangoi, J.K. AU - Rosenzweig, J.B. AU - Wang, B. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Simulations of Nanoblade Cathode Emissions with Image Charge Trapping for Yield and Brightness Analyses J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Laser-induced field emission from nanostructures as a means to create high brightness electron beams has been a continually growing topic of study. Experiments using nanoblade emitters have achieved peak fields upwards of 40 GV/m according to semi-classical analyses, begging further theoretical investigation. A recent paper has provided analytical reductions of the common semi-infinite Jellium system for pulsed incident lasers. We utilize these results to further understand the physics underlying electron rescattering-type emissions. We numerically evaluate this analytical solution to efficiently produce spectra and yield curves. The effect of space-charge trapping at emission may be simply included by directly modifying these spectra. Additionally, we use a self-consistent 1-D time-dependent Schrödinger equation with an image charge potential to study the same system as a more exact, but computationally costly, approach. With these results we may finally investigate the mean transverse energy and beam brightness at the cathode in these extreme regimes. PB - JACoW Publishing CP - Geneva, Switzerland SP - 535 EP - 538 KW - electron KW - brightness KW - laser KW - emittance KW - scattering DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA86 UR - https://jacow.org/napac2022/papers/tupa86.pdf ER - TY - CONF AU - Manwani, P. AU - Ancelin, H.S. AU - Andonian, G. AU - Fukasawa, A. AU - Lawler, G.E. AU - Majernik, N. AU - Naranjo, B. AU - Rosenzweig, J.B. AU - Sakai, Y. AU - Williams, O. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Simulations for the Space Plasma Experiments at the SAMURAI Lab J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Plasma wakefield acceleration using the electron linear accelerator test facility, SAMURAI, can be used to study the Jovian electron spectrum due to the high energy spread of the beam after the plasma interaction. The SAMURAI RF facility which is currently being constructed and commissioned at UCLA, is is capable of producing beams with 10 MeV energy, 2 nC charge, and 200 fsec bunch lengths with a 4 um emittance. Particle-in-cell (PIC) simulations are used to study the beam spectrum that would be generated from plasma interaction. Experimental methods and diagnostics are discussed in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 539 EP - 541 KW - electron KW - plasma KW - simulation KW - experiment KW - radiation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA87 UR - https://jacow.org/napac2022/papers/tupa87.pdf ER - TY - CONF AU - Hodgetts, T.J. AU - Agustsson, R.B. AU - Chen, Y.C. AU - Denham, P.E. AU - Fisher, A.C. AU - Jin, J. AU - Murokh, A.Y. AU - Musumeci, P. AU - Park, Y. AU - Ruelas, M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Compact Inter-Undulator Diagnostic Assembly for TESSA-515 J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Beamline space is a very expensive and highly sought-after commodity, which makes the creation of compact integrated optics and diagnostics extremely valuable. The FAST- GREENS experimental program aims at demonstrating 10 % extraction efficiency from a relativistic electron beam using four helical undulators operating in the high gain TESSA regime. The inter-undulator gap needs to be as short as possible (17 cm in the current plans) to maximize the output power. Within this short distance, we needed to fit two focusing quadrupoles, a variable strength phase shifter, a transverse profile monitor consisting of a YAG-OTR combination for co-aligning the electron beam and laser, and an ion pump. By making the quadrupoles tunable with a variable gradient, in combination with vertical displacement, we can meet the optics requirements of matching the beam transversely to the natural focusing of the undulators. The two quadrupoles in conjunction with the electromagnetic dipole also serve as a phase shifter to realign the radiation and the bunching before each undulator section. This paper will discuss the mechanical design of this inter-undulator break section and its components. PB - JACoW Publishing CP - Geneva, Switzerland SP - 732 EP - 734 KW - undulator KW - quadrupole KW - electron KW - radiation KW - diagnostics DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-WEPA44 UR - https://jacow.org/napac2022/papers/wepa44.pdf ER - TY - CONF AU - Lawler, G.E. AU - Majernik, N. AU - Mann, J.I. AU - Montanez, N. AU - Rosenzweig, J.B. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Development of Nanopatterned Strong Field Emission Cathodes J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Increasing brightness at the cathode is highly desirable for a diverse suite of applications in the electron accelerator community. These applications range from free electron lasers to ultrafast electron diffraction. Many options for higher brightness cathodes are under investigation notably semiconductor cathodes. We consider here the possibility for an alternative paradigm whereby the cathode surface is controlled to reduce the effective area of illumination and emission. We fabricated nanoblade metallic coated cathodes using common nanofabrication techniques. We have demonstrated that a beam can be successfully extracted with a low emittance and we have reconstructed a portion of the energy spectrum. As a result of our particular geometry, our beam possesses a notably high aspect ratio in its transverse plane. We can now begin to consider modifications for the production of intentionally patterned beams such as higher aspect ratios and hollow beams. PB - JACoW Publishing CP - Geneva, Switzerland SP - 863 EP - 865 KW - cathode KW - electron KW - laser KW - brightness KW - simulation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THYD5 UR - https://jacow.org/napac2022/papers/thyd5.pdf ER - TY - CONF AU - Burger, N. AU - Andonian, G. AU - Cook, N.M. AU - Denham, P.E. AU - Diaw, A. AU - Gavryushkin, D.I. AU - Hodgetts, T.J. AU - Lamure, A.-L.M.S. AU - Musumeci, P. AU - Norvell, N.P. AU - Ody, A. AU - Ruelas, M. AU - Welsch, C.P. AU - Yadav, M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Experimental Characterization of Gas Sheet Transverse Profile Diagnostic J2 - Proc. of NAPAC2022, Albuquerque, NM, USA, 07-12 August 2022 CY - Albuquerque, NM, USA T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Transverse profile diagnostics for high-intensity beams require solutions that are non-intercepting and single-shot. In this paper, we describe a gas-sheet ionization diagnostic that employs a precision-shaped, neutral gas jet. As the high-intensity beam passes through the gas sheet, neutral particles are ionized. The ionization products are transported and imaged on a detector. A neural-network based reconstruction algorithm, trained on simulation data, then outputs the initial transverse conditions of the beam prior to ionization. The diagnostic is also adaptable to image the photons from recombination. Preliminary tests at low energy are presented to characterize the working principle of the instrument, including comparisons to existing diagnostics. The results are parametrized as a function of beam charge, spot size, and bunch length. PB - JACoW Publishing CP - Geneva, Switzerland SP - 907 EP - 909 KW - diagnostics KW - electron KW - laser KW - operation KW - MMI DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THZE4 UR - https://jacow.org/napac2022/papers/thze4.pdf ER -