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At least 379 records · Page 21

Electron Ion Collider Strong Hadron Cooling Injector and ERL

Intra-beam Scattering (IBS) and other diffusion mechanisms in the EIC Hadron Storage Ring (HSR) degrade the beam emittances during a store, with growth times of about 2 hours at the nominal proton energies of 275GeV, 100 GeV, and 41 GeV. Strong Hadron Cooling (SHC) can maintain good hadron beam quality and high luminosity during long collision stores. A novel cooling method ’ Coherent electron Cooling (CeC) ’ is chosen as the baseline SHC method, due to its high cooling rates. An Energy Recovery Linac (ERL) is used to deliver an intense high-quality electron beam for cooling. In this paper, we discuss the beam requirements for SHC-CeC and describe the current status of the injector and ERL designs. Two designs of injector and ERL will be presented: one for dedicated SHC and another one for SHC with precooler.

Wang, E.↗

Experimental Studies of Single Invariant Quasi-Integrable Nonlinear Optics at IOTA

The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report on run 1 results of experimental studies of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread, dynamic aperture, and invariant conservation. We also outline current simulation and hardware improvement efforts for run 2, planned for fall of 2019.

43 PARTICLE ACCELERATORS↗

Online Modelling and Optimization of Nonlinear Integrable Systems

Nonlinear integrable optics was recently proposed as a design approach to increase the limits on beam brightness and intensity imposed by fast collective instabilities. To study these systems experimentally, a new research electron and proton storage ring, the Integrable Optics Test Accelerator, was constructed and recently commissioned at Fermilab. Beam-based diagnostics and online modelling of nonlinear systems presents unique challenges - in this paper, we report on our efforts to develop optimization methods suited for such lattices. We explore the effectiveness of neural networks as fast online surrogate estimators, and integrate them into a beam-based tuning algorithm. We also develop a method of knob dimensionality reduction and subsequent robust multivariate optimization for maximizing key performance metrics under complicated lattice optics constraints.

43 PARTICLE ACCELERATORS↗

A New PCB Rotating Coil at NSLS-II

Several R&D projects are underway at NSLS-II towards an upgrade of its storage ring with a new lattice that will use high field magnets with small bores of 16-22 mm. A large fraction of the high field magnets are expected to be of permanent magnet technology that will require precise magnetic measurements and field harmonics corrections. A new magnetic measurement bench has been built based on a printed circuit board (PCB) coil of 12 mm diameter and 270 mm active length. This PCB coil has the capabil-ity of measuring field quality to a level of 10 ppm of the main field up to the 15th harmonic with a sensitivity between 0.01 m2 and 0.02 m2 at the reference radius of 5 mm. This paper will describe the main features of the rotating coil bench and discuss the measurement results of a permanent-magnet Halbach quadrupole of 12.7 mm bore diameter.

43 PARTICLE ACCELERATORS↗

Analog Signal Multiplexing System for the Iota Proton Injector

The Fermilab Accelerator Science and Technology (FAST) Facility at FNAL is a dedicated research and development center focused on advancing particle accelerator technologies for future applications worldwide. Currently, a key objective of FAST Operations is to commission the 2.5 MeV IOTA Proton Injector (IPI) and enable proton injection into the Integrable Optics Test Accelerator (IOTA) storage ring. The low and medium-energy sections of the IPI include four frame-style dipole trims and two multi-function correctors with independently controlled coils, requiring readout of 32 analog channels for current and voltage monitoring in total. To reduce cost and optimize rack space within the PLC-based control system, a 32-to-4 analog signal multiplexing system was designed and implemented. This system enables real-time readback of excitation parameters from all magnetic correctors. This paper presents the design, construction, implementation, and performance of the multiplexing system.

MacLean, Daniel R. [Fermilab] (ORCID:0000000210103↗

Analysis of the elliptic integrable non-linear system in IOTA using tracking of a single electron

Integrable nonlinear lattices that can be realized in practical accelerators are of great interest, as they offer the potential to support high-intensity beams via Landau damping of collective instabilities. One such system, based on an elliptic potential, has been extensively studied at the IOTA storage ring at Fermilab. The analysis of strongly nonlinear dynamics with multi-particle bunches is challenging due to the rapid decoherence of kicked beams. IOTA has the capability to track single electrons using linear multi-anode photomultiplier tubes for simultaneously measuring transverse coordinates and arrival times of synchrotron-radiation pulses. This technology enables the full reconstruction of turn-by-turn positions and momenta in all three planes for a single particle. Using this apparatus, we measured the dependence of small-amplitude tunes on the strength of the nonlinear magnet, as well as tunes dependence on oscillations amplitudes.

Romanov, A. [Fermilab]↗

Current status of the electron transport line from RCS to ESR: RTE line

The electron injection system of the U.S. Electron-Ion Collider (EIC) is located outside of the RHIC tunnel. Electrons beams accelerated by the Rapid Cycling Synchrotron (RCS) must be transported to the Electron Storage Ring (ESR), which resides within the RHIC tunnel. To accomplish this, a dedicated beam transport line, referred to as RTE (RCS-to-ESR) line is being designed. The proposed conceptual design comprises three main sections; RCS extraction, a vertical bend and dispersion suppression region, and ESR injection matching. The extraction section uses pulsed kickers and septum magnets to achieve a total deflection angle of 3 degrees. To align the injection section with ESR, the beamline must provide a vertical elevation of 1.68 m, and an array of FODO cells is used to suppress the vertical dispersion. The total length of the RTE line is approximately 133 m, and this paper presents the current design status and considerations for this transport line.

Accelerator Physics↗

Design of an optical amplifier for amplified OSC in IOTA facility at Fermilab

Optical stochastic cooling (OSC) is a cutting-edge beam cooling technology to reduce, control the 3 dimensional spread and the motion of particle beams. It has recently been successfully, experimentally, demonstrated in Fermilab's IOTA storage ring, marking a major step forward in beam cooling. OSC has the potential to significantly improve both the performance and flexibility as a beam cooling system. One promising way to boost OSC performance is by adding a high-gain optical amplifier. However, this amplifier must be carefully designed to meet the specific constraints of the OSC system. A major challenge lies in the limited optical delay, which is just 6 mm for the case of IOTA, set by the beam bypass, restricts us to use a short-length gain medium. This, along with IOTA’s high repetition rate and the relatively long duration of the optical pulses, limits the peak power available for the pump laser without damaging the crystal, which is crucial for achieving strong nonlinear gain. Additionally, it's essential to preserve the phase coherence of the undulator radiation during amplification, which further complicates the amplifier design. This report details a specialized amplifier setup that addresses these challenges, includes simulations of the integrated system, and summarizes the latest experimental progress and results.

Mondal, Abhishek [Fermilab]↗

DEVELOPMENT OF A PROTOTYPE 197 MHz CRAB CAVITY FOR THE ELECTRON-ION COLLIDER AT JLAB

Thomas Jefferson National Accelerator Facility (JLab) is currently developing a prototype 197MHz Radio-Frequency Dipole (RFD) crab cavity as part of the Electron-Ion Collider (EIC) to be built at Brookhaven National Laboratory (BNL). Cryomodules containing these cavities will be part of the Hadron Storage Ring (HSR) of the EIC. The prototype cavity is constructed primarily of formed niobium sheets of thickness 4.17mm, with machined niobium parts used as interfaces where tight tolerancing is required. The cavity?s large size and complex features present sever-al challenges in fabrication, tuning, and RF testing. Structural and forming analyses have been carried out to optimize the design and fabrication processes. An overview of the design phase and the current state of fabrication are presented in this paper.

Huque, Naeem↗

Demonstration of Magnetron as an Alternative RF Source for SRF Accelerators

Magnetron has been considered as alternate high-efficiency, low-cost RF sources for linacs and storage rings [1] for national labs and industrial applications. After the demonstration of magnetrons power to drive and combine for a radio frequency cavity at 2450 MHz in CW mode, we have used trim coils adding to a water-cooled magnetron and amplitude modulation feedback to further suppress the side-band noise to -46.7 dBc level. We also demonstrated the phase-locking to an industrial grade cooking magnetron transmitter at 915 MHz with a 75 kW CW power delivered to a water load by using a -26.6 dBc injection signal [2]. The sideband noise from the 3-Phase SCRs DC power supply can be reduced to -16.2 dBc level. Further noise reduction and their power combining scheme using magic-tee and cavity type combiners for higher power application (2x75kW) are to be presented. We intent to use one power station to drive the normal conducting and superconducting RF cavities for the inductrial linac. We also going to demonstarte a vertical SRF cavity test with a high input coupling Q using a 2.45GHz magnetron and comparing with a baseline test result using a solid state amplifier.

Wang, H.↗

Innovations in optimization and control of accelerators using methods of differential geometry and genetic algorithms (Final Report)

Online tuning of particle accelerators is necessary in order to achieve optimal machine performance. However, it is also a major challenge due to the large parameter space which must be searched and the fact that many of the desir- able objectives compete with one another, and so will not reach their optimal values simultaneously. In order to mitigate these issues, we have explored using dimension-reduction techniques to reduce the size of the parameter space which must be searched and multi-objective genetic algorithms to obtain the sets of tuning parameters which provide pareto-optimal values for the objectives. These methods have enabled us to obtain improved values of the vertical emittance at the Cornell Electron Storage Ring (CESR), and to do so with greater control of orbit errors. Algorithmic tuning is a multidisciplinary endeavour, requiring expertise in beam dynamics, diagnostics, control systems and computer science, and thus a key practical problem is to formulate a common language in which experts with different specialties can communicate. We developed a solution to this problem in the form of a generic accelerator software interface that allows for rapid prototyping of optimization and control algorithms. Our interface is built on the Experimental Physics and Industrial Control Systems (EPICS) and makes possible testing control code in simulation before deployment on real accelerators, as well as deployment of third-party optimization code.

43 PARTICLE ACCELERATORS↗

Tests and Field Mapping of RODM01 Septum Magnet

RODM01 is a septum magnet located in the extraction region of LANSCE Proton Storage Ring. Tests and field mapping of RODM01 Set #2 were performed on 02/04/2020 by members of AOT-MDE, AOT-RFE and AOT-AE Groups. Setups of test and mapping are presented. Magnetic field measurements was performed using Hall probe. Results of measurements are almost identical to that of RODM01 Set #1 performed in July 2018. Trim coil current of magnet selected to be as - 9.28 A.

43 PARTICLE ACCELERATORS↗

Mitigation of Beam Losses in LANSCE Linear Accelerator

Suppression of beam losses is essential for successful operation of high-intensity accelerator facility. The LANSCE accelerator started routine operation in 1972 as a 0.8 MW average proton beam power facility for meson physics research, and delivered highpower beam for a quarter century. The accelerator currently delivers 100 MeV proton beam to Isotope Production Facility (IPF) and 800 MeV H- beams to various experimental areas. The accelerator is equipped with two independent injectors for H + and H - beams, merging at the entrance of a 201.25 MHz Drift Tube Linac (DTL). The DTL performs acceleration up to the energy of 100 MeV. After the DTL, the Transition Region beamline directs a 100 MeV proton beam to the Isotope Production Facility, while the H - beam is accelerated up to the final energy of 800 MeV in an 805- MHz Coupled Cavity Linac. The H - beams, created with different time structure by a lowenergy chopper, are distributed in the Switch Yard (SY) to four experimental areas: the Lujan Neutron Scattering Center equipped with a Proton Storage Ring (PSR), the Weapons Neutron Research facility (WNR), the Proton Radiography facility (pRad), and the Ultra-Cold Neutron facility (UCN). Multi-beam operation requires careful control of accelerator tune to minimize beam losses. In this paper we review main effects affecting beam losses in LANSCE linear accelerator and discuss methods to reduce them.

43 PARTICLE ACCELERATORS↗

Radial Shift Lattice Design using BMAD toolkit

The electron-ion collider (EIC) conceptual design [1] requires that the hadron storage ring (HSR) be able to demonstrate radial shifts using a dual rigidity system. The dual rigidity system is a system in which the dipoles in the utility straight sections(USS) of the EIC lattice have a different rigidity than the arc dipoles thus affecting the beam orbit in the lattice arcs. This difference in rigidity allows the orbital offset in the arc magnets to reach approximately 18.7 mm offset, with a circumference lengthening of 73.2 mm.

43 PARTICLE ACCELERATORS↗

Measurement of Spontaneous Undulator Radiation Statistics Generated by a Single Electron (URSSE)

As previously stated in the experiment proposal [1], the goal of the URSSE experiment was to study statistical properties of the undulator radiation generated by a single electron, circulating inthe IOTA storage ring. Namely, the idea was to study the distribution of the number of photons detected in a certain time window, and the distribution of the inter-arrival times of the photons. We wanted to see if the photostatistics was exactly Poissonian, as predicted or if there was some deviation towards Sub-Poissonian light, similar to what was observed in another study.

43 PARTICLE ACCELERATORS↗

High power coupler development for EIC

The synchrotron radiation loss in EIC Electron Storage Ring is as high as up to 10 MW. This energy loss will be compensated by 17 2K 591 MHz single-cell SRF cavities with a combined total of 34 high power fundamental power couplers. Each power coupler will operate 92% of revolution time CW and ~8% of revolution time with 400 kW forward power due to the beam abort gap. To satisfy the EIC needs, we developed two 500 kW standing-wave FPC designs at BNL based on either a BeO and an Al 2 O 3 RF window. This paper will briefly summarize test results of the BeO window FPC , and describe the design development of the Al 2 O 3 window based FPC.

43 PARTICLE ACCELERATORS↗

Enhanced Beam Diagnostics with Existing BPPMs via GPU-powered Multi-Particle Simulation

This research aims to utilize the multi-particle code, High-Performance Simulator (HPSim), to realistically model the Side-Coupled-Cavity Linac (CCL) lattice of the LANSCE accelerator. This new model would allow us to predict the beam’s bunch length (the longitudinal spread), which is unavailable for individual accelerating modules or only accessible at the end of the linac. However, a correct bunch length is critical for the high-energy beam transport after the CCL. Its impact would be most significant in the Proton Storage Ring (PSR), where we should be able to reduce losses for the circulating beam. The PSR is scheduled to have a 25% current increase for the neutron spallation target upgrade at the Lujan Center. A highly bunched beam would be necessary to reduce the particle losses and lower the radiation levels produced from the ring. A realistic HPSim model with >1M macro-particles can help tackle the beam losses at the sub-percent level. This new work would also create a realistic surrogate model for future machine learning projects.

43 PARTICLE ACCELERATORS↗

Instabilities driven by the fundamental crabbing mode

The Electron Ion Collider (EIC) requires crab cavities to correct for crossing angle effects. These cavities produce a time varying horizontal kick that makes the collision head on in the center of mass frame of the bunches. This results in a luminosity that is very close to the the luminosity obtained without a crossing angle. Producing the kick requires a transverse RF field. This field requires a superconducting resonator and reasonable power levels require loaded quality factors of order a million. This results is a very large transverse impedance for the crabbing mode. The horizontal beta function is large and this, coupled with the large transverse impedance of the resonator can lead to strong instabilities. In the first section of the paper a simple model is used to describe the situation without feedback. There are large ranges of tune leading to strong instabilities in both the electron and hadron storage rings of the EIC. These estimates are confirmed with simulations. In the second section, RF feedback is used to reduce the apparent impedance of the crabbing mode. Simulating the actual feedback would require both a significant rewrite of the tracking code and a significant reduction in computational speed. Instead, the apparent impedance is fitted using one pole filters, which allows use of the existing simulation code. In the third section a transverse damping system is outlined.

43 PARTICLE ACCELERATORS↗