TY - CONF AU - Barkley, W.C. AU - Bingham, D.A. AU - Borden, M.J. AU - Burkhart, J.A. AU - Evans, D.J. AU - Lyles, J.T.M. AU - Montross, J.P. AU - O’Hara, J.F. AU - Roller, B.J. AU - Sanchez Barrueta, M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Diagnoses and Repair of a Crack in the Drift Tube LINAC Accelerating Structure at LANSCE 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 - Many were perplexed at the inability of Module 3 at LANSCE to operate at peak power and duty factor while running production beam. During the 2018 production run, the DTL began to intermittently break down, leading to a series of root cause investigations. These analyses included eliminating the usual suspects: vacuum leak, debris in tank, driveline window, power coupler, etc. The throttling back of repetition rate from 120 to 60 Hz allowed continued production with a diminished beam, one that reduced neutron flux to three experimental areas. During the annual shutdown in 2019, a more thorough investigation involving the use of x-ray detection, high-resolution cameras and IR detection through site glass windows was performed. After a tenacious search, a 30 cm long crack was discovered in a weld at one of the ion pump port grates. Inaccessibility for welding from the outside and in a confined space, non-intrusive repairs were tried first but were unsuccessful. Ultimately, an expert welder entered the tank to weld the crack under unfamiliar welding conditions. This paper describes the diagnoses, non-intrusive solutions and ultimate repair of the crack in the accelerating structure. PB - JACoW Publishing CP - Geneva, Switzerland SP - 19 EP - 21 KW - vacuum KW - experiment KW - detector KW - linac KW - drift-tube-linac DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOYE4 UR - https://jacow.org/napac2022/papers/moye4.pdf ER - TY - CONF AU - Jaworski, M.A. AU - Moir, D.C. AU - Szustkowski, S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Uncertainty Quantification of Beam Parameters in a Linear Induction Accelerator Inferred from Bayesian Analysis of Solenoid Scans 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 - Linear induction accelerators (LIAs) such as the DARHT at Los Alamos National Laboratory make use of the beam envelope equation to simulate the beam and design experiments. Accepted practice is to infer beam parameters using the solenoid scan technique with optical transition radiation (OTR) beam profiles. These scans are then analyzed with an envelope equation solver to find a solution consistent with the data and machine parameters (beam energy, current, magnetic field, and geometry). The most common code for this purpose with flash-radiography LIAs is xtr [1]. The code assumes the machine parameters are perfectly known and that beam profiles will follow a normal distribution about the best fit and solves by minimizing a chi-square-like metric. We construct a Bayesian model of the beam parameters allowing maching parameters, such as solenoid position, to vary within reasonable uncertainty bounds. Posterior distribution functions are constructed using Markov-Chain Monte Carlo (MCMC) methods to evaluate the accuracy of the xtr solution uncertainties and the impact of finite precision in measurements. PB - JACoW Publishing CP - Geneva, Switzerland SP - 34 EP - 36 KW - solenoid KW - experiment KW - electron KW - induction KW - space-charge DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOZD4 UR - https://jacow.org/napac2022/papers/mozd4.pdf ER - TY - CONF AU - Xu, H. AU - Bradley, M.R. AU - Duffy, L.D. AU - Holloway, M.A. AU - Upadhyay, J. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Ceramic Enhanced Accelerator Structure Low Power Test and Designs of High Power and Beam Tests 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 ceramic enhanced accelerator structure (CEAS) uses a concentric ceramic ring placed inside a metallic pillbox cavity to significantly increase the shunt impedance of the cavity. Single cell standing wave CEAS cavities are designed, built, and tested at low power at 5.1 GHz. The results indicate 40% increase in shunt impedance compared to that of a purely metallic pillbox cavity. A beam test setup has been designed to use a single cell CEAS cavity to modulate a 30-keV direct-current (DC) electron beam at an accelerating gradient of 1 to 2 MV/m to verify the beam acceleration capability of the CEAS concept and to study the potential charging effect on the ceramic component during the operation. Another single cell standing wave CEAS cavity has been designed for high power test at 5.7 GHz for the high accelerating gradient capability. PB - JACoW Publishing CP - Geneva, Switzerland SP - 49 EP - 51 KW - cavity KW - electron KW - impedance KW - accelerating-gradient KW - simulation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOZE4 UR - https://jacow.org/napac2022/papers/moze4.pdf ER - TY - CONF AU - Edelen, J.P. AU - Abell, D.T. AU - Brown, K.A. AU - Bruhwiler, D.L. AU - Calder, S. AU - Coleman, S.J. AU - Cook, N.M. AU - Diaw, A. AU - Edelen, A.L. AU - Einstein-Curtis, J.A. AU - Hall, C.C. AU - Hoffmann, C.M. AU - Huang, E.-C. AU - Kilpatrick, M.C. AU - Nash, B. AU - O’Shea, B.D. AU - Piot, P. AU - Pogorelov, I.V. AU - Roussel, R.J. AU - Tennant, C. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Facilitating Machine Learning Collaborations Between Labs, Universities, and Industry 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 - It is clear from numerous recent community reports, papers, and proposals that machine learning is of tremendous interest for particle accelerator applications. The quickly evolving landscape continues to grow in both the breadth and depth of applications including physics modeling, anomaly detection, controls, diagnostics, and analysis. Consequently, laboratories, universities, and companies across the globe have established dedicated machine learning (ML) and data-science efforts aiming to make use of these new state-of-the-art tools. The current funding environment in the U.S. is structured in a way that supports specific application spaces rather than larger collaboration on community software. Here, we discuss the existing collaboration bottlenecks and how a shift in the funding environment, and how we develop collaborative tools, can help fuel the next wave of ML advancements for particle accelerators. PB - JACoW Publishing CP - Geneva, Switzerland SP - 164 EP - 169 KW - controls KW - simulation KW - software KW - operation KW - framework DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOPA55 UR - https://jacow.org/napac2022/papers/mopa55.pdf ER - TY - CONF AU - Howard, M.R. AU - Coleman, J.E. AU - Lidia, S.M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Studying the Emission Characteristics of Field Emission Cathodes with Various Geometries 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 cathode test stand (CTS) at LANL is designed to hold off voltages of up to 500kV and can supply pulse durations up to 2.6 μs. Using this test stand, we are able to test both field emission and photocathodes with different geometries and materials at various pulse lengths and PFN voltages. Currently, the test stand is used to evaluate field emission using a velvet cathode over various pulse lengths. The CTS employs various diagnostic tools, including E-dots, B-dots, and a scintillator coupled with a pepperpot mask in order to measure the extracted voltage, current, beam distribution, and transverse emittance. Xenos [1] has been used to create and simulate diode geometries that permits study to optimize various beam parameters. These geometries include changing the size and recess of the cathode as well as implementing a Pierce geometry. Here, we will discuss comparisons for various simulated cathodes and how changes in geometry impact given beam parameters. PB - JACoW Publishing CP - Geneva, Switzerland SP - 226 EP - 228 KW - cathode KW - emittance KW - experiment KW - ECR KW - simulation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-MOPA79 UR - https://jacow.org/napac2022/papers/mopa79.pdf ER - TY - CONF AU - Bruhaug, G.M. AU - Collins, G.W. AU - Freeman, M.S. AU - Merrill, F.E. AU - Neukirch, L.P. AU - Rinderknecht, H.G. AU - Rygg, J.R. AU - Shaw, J.L. AU - Wei, M.S. AU - Wilde, C. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Analysis Methods for Electron Radiography Based on Laser-Plasma Accelerators 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 - Analysis methods are presented for determining the res-olution of both contact and projected electron radiography based on a laser-plasma accelerator. A means to determine the field strength of the electric/magnetic fields generated when a laser is incident on an object of interest is also outlined. Broad radiography results are reported and future plans for the diagnostic technique are outlined. PB - JACoW Publishing CP - Geneva, Switzerland SP - 274 EP - 277 KW - laser KW - electron KW - plasma KW - target KW - experiment DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUXD4 UR - https://jacow.org/napac2022/papers/tuxd4.pdf ER - TY - CONF AU - Gorelov, D.V. AU - Barraza, J. AU - Dimitrov, D.A.D. AU - Draganić, I. AU - Henestroza, E. AU - Kurennoy, S.S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - LANSCE Modernization Project at LANL 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 - In the framework of LANSCE Accelerator Modernization Project preliminary research, during evaluation of critical technology elements it was found that the proposed RFQ design had not yet been demonstrated experimentally worldwide. Such an RFQ should combine the ability of traditional light ion RFQs (i.e., [1]) and the flexibility of acceleration of pre-bunched beams, like RFQs for heavy ions [2]. The proposed RFQ should be able to accelerate H⁺ and H⁻ beams with 35-mA beam current from 100 keV to 3 MeV and at the same time preserve the prescribed macro-bunch beam time structure required by experiments. New algorithms for RFQ geometry generation have been proposed, and optimization algorithms are being developed at LANL. LAMP demonstration plans also include development of a new set of electrodes for the existing RFQ at our Test Stand that will allow us to demonstrate the critical technology ahead of time in a laboratory experimental setup with low duty factor and low energy. PB - JACoW Publishing CP - Geneva, Switzerland SP - 443 EP - 445 KW - rfq KW - simulation KW - experiment KW - proton KW - LEBT DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA42 UR - https://jacow.org/napac2022/papers/tupa42.pdf ER - TY - CONF AU - Baily, S.A. AU - Atencio, B.C. AU - Braido, A.J. AU - Hatch, C.D. AU - Hill, J.O. AU - Johnson, S.M. AU - Kennel, L.S. AU - Pieck, M. AU - Walker, L.E. AU - Watkins, H.A. AU - Westbrook, E.E. AU - Xu, K. AU - Zimmermann, D.D. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Upgrade from ADCs with Centrally Scheduled Triggers to Continually Triggered Waveform Digitizers 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 Los Alamos Neutron Science Center (LANSCE) control system includes many data channels that are timed and flavored, i.e., users can specify the species of beam and time within the beam pulse at which data are reported. The legacy LANSCE control system accom-plished this task by queuing up application software-initiated requests and scheduling Analog to Digital Con-verter (ADC) readout with custom programmable time-delay gated and multiplexed Remote Information and Control Equipment (RICE). This year we upgraded this system to a new Experimental Physics and Industrial Control System (EPICS) system that includes signal ded-icated waveform digitizer. An appropriate subset of the data is then returned as specified by each client. This is made possible by improvements to EPICS software, a Commercial Off-The-Shelf (COTS) Field Programmable Gate Array (FPGA) Mezzanine Card (FMC) based ADC and a COTS VPX FPGA card with EPICS embedded on a soft-core processor. This year we upgraded over 1200 waveform channels from RICE to the new TDAQ (Timed/flavored Data Acquisition) system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 452 EP - 454 KW - EPICS KW - controls KW - FPGA KW - experiment KW - timing DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA47 UR - https://jacow.org/napac2022/papers/tupa47.pdf ER - TY - CONF AU - Batygin, Y.K. AU - Kurennoy, S.S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Effect of Lattice Misalignments on Beam Dynamics in LANSCE Linear 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 - Accelerator channel misalignments can significantly affect beam parameters in long linear accelerators. Measurements of misalignments of the LANSCE linac lattice elements was performed by the Mechanical Design Engineering Group of the Los Alamos Accelerator Operations and Technology Division. In order to determine effect of misalignment on beam parameters in LANSCE linac, the start-to-end simulations of LANSCE accelerator were performed using Beampath and CST codes including measured displacements of quadrupoles and accelerating tanks. Simulations were done for both H⁺ and H⁻ beams with various beam flavors. Effect of misalignments was compared with those due to beam space charge and distortion of RF field along the channel. Paper presents results of simulation and comparison with experimental data of beam emittance growth along the machine. PB - JACoW Publishing CP - Geneva, Switzerland SP - 455 EP - 457 KW - alignment KW - emittance KW - linac KW - lattice KW - simulation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA48 UR - https://jacow.org/napac2022/papers/tupa48.pdf ER - TY - CONF AU - Hall, T.W. AU - Lyles, J.T.M. AU - Poudel, A. AU - Waghmare, A.S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Initial Results of the 201.25 MHz Coaxial Window Test Stand 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 - We have recently commissioned an RF window test stand for the Drift Tube Linear Accelerator (DTL) portion of the Los Alamos Neutron Science Center (LANSCE). The window test stand consists of two RF windows that create a vacuum chamber which allows the windows to be tested to the peak power levels used in the DTL. Initial results clearly indicated multipactoring due to the increase of pressure at specific regions of peak forward power levels. Temperature measured at various azimuthal locations on both windows showed increased multipactor heating on the downstream window versus the upstream window. We present the effect of the titanium nitride coating that is presently applied to windows on both multipactor and window temperature. These results are discussed with respect to their impact on the LANSCE DTL performance. PB - JACoW Publishing CP - Geneva, Switzerland SP - 458 EP - 461 KW - multipactoring KW - Windows KW - vacuum KW - DTL KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA52 UR - https://jacow.org/napac2022/papers/tupa52.pdf ER - TY - CONF AU - Huang, C.-K. AU - Beznosov, O. AU - Burby, J.W. AU - Carlsten, B.E. AU - Dilts, G.A. AU - Domine, J. AU - Garimella, R. AU - Kim, A. AU - Kwan, T.J. AU - Li, F.Y. AU - Rakotoarivelo, H.N. AU - Robey, R.W. AU - Shen, B. AU - Tang, Q. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Modeling of Nonlinear Beam Dynamics via a Novel Particle-Mesh Method and Surrogate Models with Symplectic Neural Networks 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 self-consistent nonlinear dynamics of a relativistic charged particle beam, particularly through the interaction with its complete self-fields, is a fundamental problem underpinning many accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. A novel self-consistent particle-mesh code, CoSyR [1], is developed based on a Lagrangian method for the calculation of the beam particles’ radiation near-fields and associated beam dynamics. Our recent simulations reveal the slice emittance growth in a bend and complex interplay between the longitudinal and transverse dynamics that are not captured in the 1D longitudinal static-state Coherent Synchrotron Radiation (CSR) model. We further show that surrogate models with symplectic neural networks can be trained from simulation data with significant time-savings for the modeling of nonlinear beam dynamics effects. Possibility to extend such surrogate models for the study of spin-orbital coupling is also briefly discussed. PB - JACoW Publishing CP - Geneva, Switzerland SP - 462 EP - 464 KW - simulation KW - network KW - electron KW - radiation KW - synchrotron-radiation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA53 UR - https://jacow.org/napac2022/papers/tupa53.pdf ER - TY - CONF AU - Koglin, J.E. AU - Coleman, J.E. AU - McKerns, M. AU - Ronquillo, D. AU - Scheinker, A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Progress Toward Improving Accelerator Performance and Automating Operations with Advanced Analysis Software 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 penetrating radiography provided by the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility is a key capability in executing a core mission of the Los Alamos National Laboratory (LANL). A new suite of software is being developed in the Python programming language to support operations of the of two DARHT linear induction accelerators (LIAs). Historical data, built as hdf5 data structures for over a decade of operations, are being used to develop automated failure and anomaly detection software and train machine learning models to assist in beam tuning. Adaptive machine learning (AML) that incorporate physics-based models are being designed to use non-invasive diagnostic measurements to address the challenge of time variation in accelerator performance and target density evolution. AML methods are also being developed for experiments that use invasive diagnostics to understand the accelerator behavior at key locations, the results of which will be fed back into the accelerator models. The status and future outlook for these developments will be reported, including how Jupyter notebooks are being used to rapidly deploy these advances as highly-interactive web applications. PB - JACoW Publishing CP - Geneva, Switzerland SP - 465 EP - 468 KW - diagnostics KW - operation KW - cathode KW - software KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA55 UR - https://jacow.org/napac2022/papers/tupa55.pdf ER - TY - CONF AU - Kurennoy, S.S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Beam Coupling Impedances of Asymmetric Components of the Scorpius Induction Linac 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 transverse beam coupling impedance of induction linacs must be minimized to avoid beam breakdown instability. The vacuum chamber of the Scorpius linac contains complicated asymmetric elements. We present calculations of the transverse impedance for three asymmetric discontinuities: (1) a pumping section between accelerating cells, which contains vacuum plenum, pumping grid, and bellows; (2) a fast flapper valve; and (3) a debris blocker at the end of the linac. The dipole transverse impedance is calculated with CST Studio using both wakefield solver and eigen solver. PB - JACoW Publishing CP - Geneva, Switzerland SP - 469 EP - 471 KW - impedance KW - resonance KW - linac KW - dipole KW - vacuum DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA56 UR - https://jacow.org/napac2022/papers/tupa56.pdf ER - TY - CONF AU - Kurennoy, S.S. AU - Batygin, Y.K. AU - Gorelov, D.V. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Electromagnetic and Beam Dynamics Modeling of the LANSCE Coupled-Cavity Linac 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 800-MeV proton linac at LANSCE consists of a drift-tube linac, which brings the beam to 100 MeV, followed by a coupled-cavity linac (CCL) consisting of 44 modules. Each CCL module contains multiple tanks, and it is fed by a single 805-MHz klystron. CCL tanks are multi-cell blocks of identical re-entrant side-coupled cavities, which are followed by drifts with magnetic quadrupole doublets. Bridge couplers - special cavities displaced from the beam axis - electromagnetically couple CCL tanks over such drifts. We have developed 3D CST models of CCL tanks. Their electromagnetic analysis is performed using MicroWave Studio. Beam dynamics is modeled with Particle Studio for bunch trains with realistic beam distributions using the CST calculated RF fields and quadrupole magnetic fields to determine the output beam parameters. Beam dynamics results are crosschecked with other multi-particle codes. PB - JACoW Publishing CP - Geneva, Switzerland SP - 472 EP - 474 KW - cavity KW - linac KW - simulation KW - emittance KW - quadrupole DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA57 UR - https://jacow.org/napac2022/papers/tupa57.pdf ER - TY - CONF AU - Kwon, S. AU - Archuleta, A.T. AU - Castellano, L.J. AU - Prokop, M.S. AU - Rose, C. AU - Torrez, P.A. AU - Van Rooy, P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Iterative Tuning of the Beam Feedforward Controller for LANSCE LINAC Digital Low Level RF Control System 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 - This paper addresses an iterative particle beam phase and amplitude feedforward controller tuning method based on the gradient search approach. The method does not need an a priori plant model as it only needs data collected in previous experimental runs. The controller is implemented on a field programmable gate array (FPGA) equipped with a real-time operating system and a network connection. Data from each RF pulse is collected and sent via the network to the FPGA for processing. The controller tuning is performed between the RF pulses. Once the tuning is performed, the controller parameters are downloaded to the controller in the FPGA and new controller parameters are applied at the upcoming RF pulse PB - JACoW Publishing CP - Geneva, Switzerland SP - 475 EP - 477 KW - controls KW - beam-loading KW - cavity KW - LLRF KW - neutron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA58 UR - https://jacow.org/napac2022/papers/tupa58.pdf ER - TY - CONF AU - Lyles, J.T.M. AU - Bratton, R.E. AU - Hall, T.W. AU - Sanchez Barrueta, M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - RF System Upgrade for Low Energy DTL Cavity at LANSCE 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 Los Alamos Neutron Science Center (LANSCE) 100-MeV Drift Tube Linac (DTL) uses four accelerating cavities. In May of 2021, a new RF amplifier system was commissioned to drive the first 4-MeV cavity. It had been powered for 30 years with a triode vacuum tube RF amplifier driven by a tetrode, along with four more vacuum tubes for anode high-voltage modulation. The new amplifier system uses one tetrode amplifier driven by a 20-kW solid state amplifier (SSA) to generate 400 kWp at 201.25 MHz. The tetrode amplifier is protected for reflected power from the DTL by a coaxial circulator. The new installation includes cRio controls and a fast protection and monitoring system capable of reacting to faults within 10 µs. A new digital low-level RF (LLRF) system has been installed that integrates I/Q signal processing, PI feedback, and feedforward controls for beam loading compensation. Issues with LLRF stability were initially encountered due to interaction from thermal-related RF phase changes. After these issues were solved, the final outcome has been a reliable new RF system to complete the overall upgrade of the LANSCE DTL RF power plant. PB - JACoW Publishing CP - Geneva, Switzerland SP - 478 EP - 481 KW - controls KW - DTL KW - LLRF KW - cavity KW - MMI DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA59 UR - https://jacow.org/napac2022/papers/tupa59.pdf ER - TY - CONF AU - Pieck, M. AU - Hatch, C.D. AU - Hill, J.O. AU - Watkins, H.A. AU - Westbrook, E.E. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - LANSCE Control System’s 50th Anniversary 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 - After almost exactly 50 years in service, the LANSCE (Los Alamos Neutron Science Center) control system has achieved a major milestone, replacing its original and reliable RICE (Remote Instrumentation and Control Equipment) with a modern customized control system. The task of replacing RICE was challenging because of its technology (late 1960’s), number of channels (>10,000), unique characteristics (all-modules data takes, timed/flavored data takes) and that it was designed as an integral part of the whole accelerator. We discuss the history, RICE integral architecture, upgrade efforts, and the new system providing cutting-edge capabilities. The boundary condition was that upgrades only could be implemented during the annual four-month accelerator maintenance outage. This led to a multi-phased project which turned out to be about an 11-year effort. PB - JACoW Publishing CP - Geneva, Switzerland SP - 482 EP - 485 KW - controls KW - EPICS KW - timing KW - network KW - data-acquisition DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA62 UR - https://jacow.org/napac2022/papers/tupa62.pdf ER - TY - CONF AU - Sanchez Barrueta, M. AU - Lyles, J.T.M. AU - Morris, M.D.M. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Analysis of Resonant Converter Topology for High-Voltage Modulators 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 - At the Los Alamos Neutron Science Center (LANSCE), we are considering various topologies to replace obsolete charging supplies and capacitor banks that provide high-voltage direct-current (DC) power to the 44, 805-MHz klystron modulators that drive the LANSCE Coupled Cavity Linac (CCL). Among the possible replacement topologies is the High Voltage Converter Modulator (HVCM), originally designed at LANSCE for use at the Spallation Neutron Source (SNS), to be used as a pulsed high-voltage power supply for klystron-based RF transmitters. The HVCM topology uses high frequency transformers with resonant LC networks for efficient energy conversion and a frequency dependent gain, which permits the use of frequency modulation as a control variable to afford pulse flattening and excellent regulation as demonstrated at SNS. A mathematical analysis is presented that links the converter resonant tank components to the frequency dependent output behavior of the converter modulator. PB - JACoW Publishing CP - Geneva, Switzerland SP - 486 EP - 489 KW - resonance KW - high-voltage KW - operation KW - impedance KW - klystron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA64 UR - https://jacow.org/napac2022/papers/tupa64.pdf ER - TY - CONF AU - Scheinker, A. AU - Dudeck, K.W. AU - Leibman, C.P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Machine Learning for the LANL Electromagnetic Isotope Separator 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 Los Alamos National Laboratory electromagnetic isotope separator (EMIS) utilizes a Freeman ion source to generate beams of various elements which are accelerated to 40 keV and passed through a 75-degree bend using a large dipole magnet with a radius of 1.2 m. The isotope mass differences translate directly to a spread in momentum, dp, relative to the design momentum p0. Momentum spread is converted to spread in the horizontal arrival location dx at a target chamber by the dispersion of the dipole magnet: dx = D(s)dp/p0. By placing a thin slit leading to a collection chamber at a location xc specific isotope mass is isolated by adjusting the dipole magnet strength or the beam energy. The arriving beam current at xc is associated with average isotope atomic mass, giving an isotope mass spectrum I(m) measured in mA. Although the EMIS is a compact system (5 m) setting up and automatically running at an optimal isotope separation profile I(m) profile is challenging due to time-variation of the complex source as well as un-modeled disturbances. We present preliminary results of developing adaptive machine learning-based tools for the EMIS beam and for the accelerator components. PB - JACoW Publishing CP - Geneva, Switzerland SP - 490 EP - 492 KW - controls KW - dipole KW - ion-source KW - feedback KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA65 UR - https://jacow.org/napac2022/papers/tupa65.pdf ER - TY - CONF AU - Van Rooy, P. AU - Archuleta, A.T. AU - Castellano, L.J. AU - Kwon, S. AU - Prokop, M.S. AU - Torrez, P.A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Improving Cavity Phase Measurements at Los Alamos Neutron Science Center 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 - Control stability of the phase and amplitude in the cavity is a significant contributor to beam performance. The ability to measure phase and amplitude of pulsed RF systems at accuracies of ± 0.1 degrees and ± 0.1 percent required for our systems is difficult, and custom-designed circuitry is required. The digital low-level RF upgrade at the Los Alamos Neutron Science Center is continuing to progress with improved cavity phase measurements. The previous generation of the cavity phase and amplitude measurement system has a phase ambiguity, which requires repeated calibrations to ascertain the correct phase direction. The new phase measurement system removes the ambiguity and the need for field calibration while improving the range and precision of the cavity phase measurements. In addition, the new digital low-level RF systems is designed to upgrade the legacy system without significant mechanical, electrical, or cabling changes. Performance data for the new phase measurement system is presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 493 EP - 495 KW - cavity KW - GUI KW - LLRF KW - controls KW - neutron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA69 UR - https://jacow.org/napac2022/papers/tupa69.pdf ER - TY - CONF AU - Xu, H. AU - Anisimov, P.M. AU - Duffy, L.D. AU - Marksteiner, Q.R. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Comparison Study on First Bunch Compressor Schemes by Conventional and Double C-Chicane for MaRIE XFEL 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 - We report our comparison study on the first stage electron bunch compression schemes at 750 MeV using a conventional and a double C-chicane for the X-ray free electron laser (XFEL) under development for the Matter-Radiation Interactions in Extremes (MaRIE) initiative at Los Alamos National Laboratory. Compared to the performance of the conventional C-chicane bunch compressor, the double C-chicane scheme exhibits the capability of utilizing the transverse momentum shift induced by the coherent synchrotron radiation in the second C-chicane to compensate that generated in the first C-chicane, resulting in a compressed electron bunch with minimized transverse momentum shift along the beam. It is also found that the double C-chicane scheme can be designed to significantly better preserve the beam emittance in the course of the bunch compression. This is particularly beneficial for the MaRIE XFEL whose lasing performance critically depends on the preservation of the ultralow beam emittance. PB - JACoW Publishing CP - Geneva, Switzerland SP - 496 EP - 498 KW - dipole KW - emittance KW - electron KW - FEL KW - radiation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA72 UR - https://jacow.org/napac2022/papers/tupa72.pdf ER - TY - CONF AU - Xu, H. AU - Beaudoin, B.L. AU - Carlsten, B.E. AU - Koeth, T.W. AU - Marksteiner, Q.R. AU - Ting, A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Design and Low Power Test of an Electron Bunching Enhancer Using Electrostatic Potential Depression 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 - We present our experimental design and low power test results of a structure for the proof-of-principle demonstration of fast increase of the first harmonic current content in a bunched electron beam, using the technique of electrostatic potential depression (EPD). A primarily bunched electron beam from an inductive output tube (IOT) at 710 MHz first enters an idler cavity, where the longitudinal slope of the beam energy distribution is reversed. The beam then transits through an EPD section implemented by a short beam pipe with a negative high voltage bias, inside which the rate of increase of the first harmonic current is significantly enhanced. An output cavity measures the harmonic current developed inside the beam downstream of the EPD section. Low power test results of the idler and the output cavities agree with the theoretical design. PB - JACoW Publishing CP - Geneva, Switzerland SP - 499 EP - 501 KW - cavity KW - electron KW - simulation KW - gun KW - experiment DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA73 UR - https://jacow.org/napac2022/papers/tupa73.pdf ER - TY - CONF AU - Xu, H. AU - Delzanno, G.L. AU - Duffy, L.D. AU - Marksteiner, Q.R. AU - Reeves, G.D. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Numerical Calculations of Wave Generation from a Bunched Electron Beam in Space 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 - We present our numerical approach and preliminary results of the calculations of whistler and X-mode wave generation by a bunched electron beam in space. The artificial generation of whistler and X-mode plasma waves in space is among the candidate techniques to accomplish the radiation belt remediation (RBR), in an effort to precipitate energetic electrons towards the atmosphere to reduce their threat to low-Earth orbit satellites. Free-space propagation of an electron pulse in a constant background magnetic field was simulated with the CST particle-in-cell (PIC) solver, with the temporal evolution of the beam recorded. The SpectralPlasmaSolver (SPS) was then modified to use the recorded electron pulse propagation to calculate the real-time plasma waves generated by the beam. SPS simulation results of the wave generation for the upcoming Beam-PIE experiment as well as an ideal bunched electron beam are shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 502 EP - 504 KW - electron KW - plasma KW - radiation KW - simulation KW - experiment DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA74 UR - https://jacow.org/napac2022/papers/tupa74.pdf ER - TY - CONF AU - Zuboraj, M.R.A. AU - Gorelov, D.V. AU - Hall, T.W. AU - Middendorf, M.E. AU - Rai, D. AU - Simakov, E.I. AU - Tajima, T. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - High Gradient Testing Results of the Benchmark a/λ=0.105 Cavity at CERF-NM 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 - This presentation will report initial results of high gradient testing of two C-band accelerating cavities fabricated at Los Alamos National Laboratory (LANL). At LANL, we commissioned a C-band Engineering Research Facility of New Mexico (CERF-NM) which has unique capability of conditioning and testing accelerating cavities for operation at surface electric fields at the excess of 300 MV/m, powered by a 50 MW, 5.712 GHz Canon klystron. Recently, we fabricated and tested two benchmark copper cavities at CERF-NM. These cavities establish a benchmark for high gradient performance at C-band and the same geometry will be used to provide direct comparison between high gradient performance of cavities fabricated of different alloys and by different fabrication methods. The cavities consist of three cells with one high gradient central cell and two coupling cells on the sides. The ratio of the radius of the coupling iris to the wavelength is a/λ=0.105. This poster will report high gradient test results such as breakdown rates as function of peak surface electric and magnetic fields and pulse heating. PB - JACoW Publishing CP - Geneva, Switzerland SP - 505 EP - 507 KW - cavity KW - GUI KW - klystron KW - coupling KW - MMI DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-TUPA75 UR - https://jacow.org/napac2022/papers/tupa75.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 - Freeman, P.M. AU - Bohon, J. AU - Gulley, M.S. AU - Huang, E.-C. AU - Malavasi, L. AU - Odegard, B. AU - Schmitz, R. AU - Smedley, J. AU - Stuart, D. AU - Yang, J. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - A Modular X-Ray Detector for Beamline Diagnostics at LANL 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 - An X-ray detector is being developed for diagnostic measurement and monitoring of the Drift Tube LINAC (DTL) at the Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Lab. The detector will consist of a row of x-ray spectrometers adjacent to the DTL that will measure the spectrum of X-rays resulting from bremsstrahlung of electrons created in vacuum by the RF. Each spectrometer will monitor a specific gap between drift tubes, and will consist of an array of scintillating crystals coupled to SiPMs read out with custom-built electronics. The spectrometer is designed with one LYSO and three NaI crystals. The LYSO provides a tagged gamma source with three peaks that are used for calibration of the NaI. A prototype of the spectrometer was tested at the LANSCE DTL to validate the feasibility of measuring gamma spectra and performing self-calibration in situ. A summary of test results with the LANSCE prototype will be presented, along with a detector system design that aims to be modular and inexpensive across all modules in the DTL. Plans for future development will be presented as well. PB - JACoW Publishing CP - Geneva, Switzerland SP - 725 EP - 727 KW - detector KW - DTL KW - diagnostics KW - shielding KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-WEPA42 UR - https://jacow.org/napac2022/papers/wepa42.pdf ER - TY - CONF AU - Knill, C.J. AU - Ago, H. AU - Batista, E. AU - Karkare, S.S. AU - Kawahara, K. AU - Moody, N.A. AU - Wang, G.X. AU - Yamaguchi, H. AU - Yang, P. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Near-Threshold Photoemission from Graphene Coated Cu Single Crystals 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 brightness of electron beams emitted from photocathodes plays a key role in the performance of x-ray free electron lasers (XFELs) and ultrafast electron diffraction (UED) experiments. In order to achieve the maximum beam brightness, the electrons need to be emitted from photocathodes with the smallest possible mean transverse energy (MTE). Recent studies have looked at the effect that a graphene coating has on the quantum efficiency (QE) of the cathode [1]. However, there have not yet been any investigations into the effect that a graphene coating has on the MTE. Here we report on MTE and QE measurements of a graphene coated Cu(110) single crystal cathode at room and cryogenic temperatures. At room temperature, a minimum MTE of 25 meV was measured at 295 nm. This MTE remained stable at 25 meV over several days. At 77 K, the minimum MTE of 9 meV was measured at 290 nm. We perform density functional theory (DFT) calculations to look at the effects of a graphene coating on a Cu(111) surface state. These calculations show that the graphene coating reduces the radius of the surface state, allowing for emission from a lower transverse energy state in comparison to bare Cu(111). PB - JACoW Publishing CP - Geneva, Switzerland SP - 776 EP - 779 KW - electron KW - cathode KW - experiment KW - cryogenics KW - brightness DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-WEPA66 UR - https://jacow.org/napac2022/papers/wepa66.pdf ER - TY - CONF AU - Scheinker, A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - 6D Phase Space Diagnostics Based on Adaptive Tuning of the Latent Space of Encoder-Decoder Convolutional Neural Networks 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 - We present a general approach to 6D phase space diagnostics for charged particle beams based on adaptively tuning the low-dimensional latent space of generative encoder-decoder convolutional neural networks (CNN). Our approach first trains the CNN based on supervised learning to learn the correlations and physics constrains within a given accelerator system. The input of the CNN is a high dimensional collection of 2D phase space projections of the beam at the accelerator entrance together with a vector of accelerator parameters such as magnet and RF settings. The inputs are squeezed down to a low-dimensional latent space from which we generate the output in the form of projections of the beam’s 6D phase space at various accelerator locations. After training the CNN is applied in an unsupervised adaptive manner by comparing a subset of the output predictions to available measurements with the error guiding feedback directly in the low-dimensional latent space. We show that our approach is robust to unseen time-variation of the input beam and accelerator parameters and a study of the robustness of the method to go beyond the span of the training data. PB - JACoW Publishing CP - Geneva, Switzerland SP - 837 EP - 841 KW - controls KW - solenoid KW - feedback KW - network KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THXD2 UR - https://jacow.org/napac2022/papers/thxd2.pdf ER - TY - CONF AU - Simakov, E.I. AU - Alexander, A.M. AU - Gorelov, D.V. AU - Hall, T.W. AU - Middendorf, M.E. AU - Rai, D. AU - Tajima, T. AU - Zuboraj, M.R.A. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Update on the Status of C-Band Research and Facilities at LANL 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 - We will report on the status of two C-band test facilities at Los Alamos National Laboratory (LANL): C-band Engineering Research Facility in New Mexico (CERF-NM), and Cathodes and Rf Interactions in Extremes (CARIE). Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a high gradient test stand powered by a 50 MW, 5.712 GHz Canon klystron. CERF-NM is the first high gradient C-band test facility in the United States. It was fully commissioned in 2021. In the last year, multiple C-band high gradient cavities and components were tested at CERF-NM. Currently we work to implement several updates to the test stand including the ability to remotedly operate at high gradient for the round-the-clock high gradient conditioning. Adding capability to operate at cryogenic temperatures is considered. The construction of CARIE will begin in October of 2022. CARIE will house a cryo-cooled copper RF photoinjector with a high quantum-efficiency cathode and a high gradient accelerator section. PB - JACoW Publishing CP - Geneva, Switzerland SP - 855 EP - 858 KW - cavity KW - cathode KW - electron KW - klystron KW - operation DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THYD3 UR - https://jacow.org/napac2022/papers/thyd3.pdf ER - TY - CONF AU - Batygin, Y.K. AU - Kurennoy, S.S. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Design of 3-GeV High-Gradient Booster for Upgraded Proton Radiography at LANSCE 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 the proton beam energy from the present 800 MeV to 3 GeV will improve the resolution of the Proton Radiography Facility at the Los Alamos Neutron Science Center (LANSCE) by a factor of 10. It will bridge the gap between the existing facilities, which covers large length scales for thick objects, and future high-brightness light sources, which can provide the finest resolution. Proton radiography requires a sequence of short beam pulses (~20 x 80 ns) separated by intervals of variable duration, from about 300 ns to 1 to 2 μs. To achieve the required parameters, the high gradient 3-GeV booster is proposed. The booster consists of 1.4 GHz buncher, two accelerators based on 2.8 GHz and 5.6 GHz high-gradient accelerating structures and 1.4 GHz debuncher. Utilization of buncher-accelerator-debuncher scheme allows us to combine high-gradient acceleration with significant reduction of beam momentum spread. Paper discusses details of linac design and expected beam parameters. PB - JACoW Publishing CP - Geneva, Switzerland SP - 891 EP - 893 KW - booster KW - proton KW - focusing KW - linac KW - quadrupole DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THZD3 UR - https://jacow.org/napac2022/papers/thzd3.pdf ER - TY - CONF AU - Kurennoy, S.S. AU - Batygin, Y.K. AU - Olivas, E.R. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Accelerating Structures for High-Gradient Proton Radiography Booster at LANSCE 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 energy of proton beam at LANSCE from 800 MeV to 3 GeV improves radiography resolution ~10 times. We proposed accomplishing such an energy boost with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual proton linac is feasible for proton radiography (pRad), which operates with short RF pulses. For a compact pRad booster at LANSCE, we have developed a multi-stage design: a short L-band section to capture and compress the 800-MeV proton beam followed by the main HG linac based on S- and C-band cavities, and finally, by an L-band de-buncher [1]. Here we present details of development, including EM and thermal-stress analysis, of proton HG structures with distributed RF coupling for the pRad booster. A simple two-cell structure with distributed coupling is being fabricated and will be tested at the LANL C-band RF Test Stand. PB - JACoW Publishing CP - Geneva, Switzerland SP - 894 EP - 896 KW - cavity KW - booster KW - linac KW - proton KW - distributed DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-THZD4 UR - https://jacow.org/napac2022/papers/thzd4.pdf ER - TY - CONF AU - Marksteiner, Q.R. AU - Anisimov, P.M. AU - Carlsten, B.E. AU - Latour, G. AU - Simakov, E.I. AU - Xu, H. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Suppressing the Microbunching Instability at ATF using Laser Assisted Bunch Compression 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 microbunching instability in linear accelerators can significantly increase the energy spread of an electron beam. The instability can be suppressed by artificially increasing the random energy spread of an electron beam, but this leads to unacceptably high energy spreads for future XFEL systems. One possibility of suppressing this instability is to use laser assisted bunch compression (LABC) instead of the second chicane in an XFEL system, thereby eliminating the cascaded chicane effect that magnifies the microbunching instability. An experiment is proposed at ATF to test this concept, and numerical simulations of the experiment are shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 914 EP - 916 KW - laser KW - electron KW - experiment KW - simulation KW - bunching DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-FRXD4 UR - https://jacow.org/napac2022/papers/frxd4.pdf ER - TY - CONF AU - Scheinker, A. AU - Roussel, R.J. ED - Biedron, Sandra ED - Simakov, Evgenya ED - Milton, Stephen ED - Anisimov, Petr M. ED - Schaa, Volker R.W. TI - Bayesian Algorithms for Practical Accelerator Control and Adaptive Machine Learning for Time-Varying Systems 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 - Particle accelerators are complicated machines with thousands of coupled time varying components. The electromagnetic fields of accelerator devices such as magnets and RF cavities drift and are uncertain due to external disturbances, vibrations, temperature changes, and hysteresis. Accelerated charged particle beams are complex objects with 6D phase space dynamics governed by collective effects such as space charge forces, coherent synchrotron radiation, and whose initial phase space distributions change in unexpected and difficult to measure ways. This two-part tutorial presents recent developments in Bayesian methods and adaptive machine learning (ML) techniques for accelerators. Part 1: We introduce Bayesian control algorithms, and we describe how these algorithms can be customized to solve practical accelerator specific problems, including online characterization and optimization. Part 2: We give an overview of adaptive ML (AML) combining adaptive model-independent feedback within physics-informed ML architectures to make ML tools robust to time-variation (distribution shift) and to enable their use further beyond the span of the training data without relying on re-training. PB - JACoW Publishing CP - Geneva, Switzerland SP - 921 EP - 926 KW - network KW - controls KW - feedback KW - experiment KW - electron DA - 2022/10 PY - 2022 SN - 2673-7000 SN - 978-3-95450-232-5 DO - doi:10.18429/JACoW-NAPAC2022-FRXE1 UR - https://jacow.org/napac2022/papers/frxe1.pdf ER -