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Wang, H.

Publications and source records attributed to Wang, H..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Operational Experience of the New Booster Cryomodule at the Upgraded Injector Test Facility

Since the early 1990s, the in­jec­tor of the CEBAF ac­cel­er­a­tor at Jef­fer­son Lab has re­lied on a nor­mal-con­duct­ing RF graded-beta cap­ture sec­tion to boost the ki­netic en­ergy of the elec­tron beam from 100 / 130 keV to 600 keV for sub­se­quent ac­cel­er­a­tion using a cry­omod­ule hous­ing two su­per­con­duct­ing 5-cell cav­i­ties sim­i­lar to those used through­out the ac­cel­er­a­tor. To sim­plify the in­jec­tor de­sign and im­prove the beam qual­ity, the nor­mal-con­duct­ing RF cap­ture sec­tion and the cry­omod­ule will be re­placed with a new sin­gle booster cry­omod­ule em­ploy­ing a su­per­con­duct­ing, β = 0.6, 2-cell-cav­ity cap­ture sec­tion and a sin­gle, β = 0.97, 7-cell cav­ity. The Up­graded In­jec­tor Test Fa­cil­ity at Jef­fer­son Lab is cur­rently host­ing the new cry­omod­ule to eval­u­ate its per­for­mance with beam be­fore in­stal­la­tion at CEBAF. While demon­strat­ing sat­is­fac­tory per­for­mance of the booster and good agree­ment with sim­u­la­tions, our beam test re­sults also speak to lim­i­ta­tions of ac­cel­er­a­tor op­er­a­tions in a noisy, ther­mally un­reg­u­lated en­vi­ron­ment.

Bruker, M. W.↗
DOE OSTI2022

Magnetron R&D Progress for High Efficiency CW RF Sources of Industrial Accelerators

After the demonstration of using high efficiency magnetron power to combine and aim to drive a radio frequency accelerator at 2450MHz in CW mode [1], we have used trim coils adding to a water-cooled magnetron and three amplitude modulation methods in an open-loop control to further suppress the 120Hz side-band noise to -46.7dBc level. We have also successfully demonstrated the phase-locking to an industrial grade cooking magnetron transmitter at 915MHz with a 75kW CW power delivered to a water load by using a -26.6dBc injection signal. The sideband noise at 360Hz from the 3-Phase SCRs DC power supply can be reduced to -16.2dBc level. Their power combing scheme and higher power application to industrial accelerators are foreseeing.

Wang, H.↗
DOE OSTI2022

Manufacturing the Harmonic Kicker Cavity Prototype for the Electron-Ion Collider

High-bunch-frequency beam-separation schemes, such as the injection scheme proposed for the Rapid Cycling Synchrotron at the Electron-Ion Collider, demand rise and fall times an order of magnitude below what can realistically be accomplished with a stripline kicker. Nanosecond-time-scale kick waveforms can instead be obtained by Fourier synthesis in a harmonically resonant quarter-wave radio-frequency cavity which is optimized for high shunt impedance. Originally developed for the Jefferson Lab Electron-Ion Collider (JLEIC) Circulator Cooler Ring, a hypothetical 11-pass ring driven by an energy-recovery linac at Jefferson Lab, our high-power prototype of such a harmonic kicker cavity, which operates at five modes at the same time, will demonstrate the viability of this concept with a beam test at Jefferson Lab. As the geometry of the cavity, tight mechanical tolerances, and number of ports complicate the design and manufacturing process, special care must be given to the order of the manufacturing steps. We present our experiences with the manufacturability of the present design, lessons learned, and first RF test results from the prototype.

Overstreet, S. A.↗
DOE OSTI2022

Manufacturing the Harmonic Kicker Cavity Prototype for the Electron-Ion Collider

High-bunch-frequency beam-separation schemes, such as the injection scheme proposed for the Rapid Cycling Synchrotron at the Electron-Ion Collider, demand rise and fall times an order of magnitude below what can realistically be accomplished with a stripline kicker. Nanosecond-time-scale kick waveforms can instead be obtained by Fourier synthesis in a harmonically resonant quarter-wave radio-frequency cavity which is optimized for high shunt impedance. Originally developed for the Jefferson Lab Electron-Ion Collider (JLEIC) Circulator Cooler Ring, a hypothetical 11-pass ring driven by an energy-recovery linac at Jefferson Lab, our high-power prototype of such a harmonic kicker cavity, which operates at five modes at the same time, will demonstrate the viability of this concept with a beam test at Jefferson Lab. As the geometry of the cavity, tight mechanical tolerances, and number of ports complicate the design and manufacturing process, special care must be given to the order of the manufacturing steps. We present our experiences with the manufacturability of the present design, lessons learned, and first RF test results from the prototype.

Overstreet, S. A.↗
DOE OSTI2022

Operational Experience of the New Booster Cryomodule at the Upgraded Injector Test Facility

Since the early 1990s, the in­jec­tor of the CEBAF ac­cel­er­a­tor at Jef­fer­son Lab has re­lied on a nor­mal-con­duct­ing RF graded-beta cap­ture sec­tion to boost the ki­netic en­ergy of the elec­tron beam from 100 / 130 keV to 600 keV for sub­se­quent ac­cel­er­a­tion using a cry­omod­ule hous­ing two su­per­con­duct­ing 5-cell cav­i­ties sim­i­lar to those used through­out the ac­cel­er­a­tor. To sim­plify the in­jec­tor de­sign and im­prove the beam qual­ity, the nor­mal-con­duct­ing RF cap­ture sec­tion and the cry­omod­ule will be re­placed with a new sin­gle booster cry­omod­ule em­ploy­ing a su­per­con­duct­ing, β = 0.6, 2-cell-cav­ity cap­ture sec­tion and a sin­gle, β = 0.97, 7-cell cav­ity. The Up­graded In­jec­tor Test Fa­cil­ity at Jef­fer­son Lab is cur­rently host­ing the new cry­omod­ule to eval­u­ate its per­for­mance with beam be­fore in­stal­la­tion at CEBAF. While demon­strat­ing sat­is­fac­tory per­for­mance of the booster and good agree­ment with sim­u­la­tions, our beam test re­sults also speak to lim­i­ta­tions of ac­cel­er­a­tor op­er­a­tions in a noisy, ther­mally un­reg­u­lated en­vi­ron­ment.

Bruker, M. W.↗
DOE OSTI2022

Digital quantum simulation of Floquet symmetry-protected topological phases

Quantum many-body systems away from equilibrium host a rich variety of exotic phenomena that are forbidden by equilibrium thermodynamics. A prominent example is that of discrete time crystals, in which time-translational symmetry is spontaneously broken in periodically driven systems. Pioneering experiments have observed signatures of time crystalline phases with trapped ions, solid-state spin systems, ultracold atoms and superconducting qubits. Here we report the observation of a distinct type of non-equilibrium state of matter, Floquet symmetry-protected topological phases, which are implemented through digital quantum simulation with an array of programmable superconducting qubits. We observe robust long-lived temporal correlations and subharmonic temporal response for the edge spins over up to 40 driving cycles using a circuit of depth exceeding 240 and acting on 26 qubits. We demonstrate that the subharmonic response is independent of the initial state, and experimentally map out a phase boundary between the Floquet symmetry-protected topological and thermal phases. Our results establish a versatile digital simulation approach to exploring exotic non-equilibrium phases of matter with current noisy intermediate-scale quantum processors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Beam test performance of a prototype module with Short Strip ASICs for the CMS HL-LHC tracker upgrade

The Short Strip ASIC (SSA) is one of the four front-end chips designed for the upgrade of the CMS Outer Tracker for the High Luminosity LHC. Together with the Macro-Pixel ASIC (MPA) it will instrument modules containing a strip and a macro-pixel sensor stacked on top of each other. The SSA provides both full readout of the strip hit information when triggered, and, together with the MPA, correlated clusters called stubs from the two sensors for use by the CMS Level-1 (L1) trigger system. Results from the first prototype module consisting of a sensor and two SSA chips are presented. The prototype module has been characterized at the Fermilab Test Beam Facility using a 120 GeV proton beam.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Global Dust Cycle and Direct Radiative Effect in E3SM Version 1: Impact of Increasing Model Resolution

Quantification of dust aerosols in Earth System Models (ESMs) has important implications for water cycle and biogeochemistry studies. This study examines the global life cycle and direct radiative effects (DREs) of dust in the U.S. Department of Energy's Energy Exascale Earth System Model version 1 (E3SMv1), and the impact of increasing model resolution both horizontally and vertically. The default 1° E3SMv1 captures the spatial and temporal variability in the observed dust aerosol optical depth (DAOD) reasonably well, but overpredicts dust absorption in the shortwave (SW). Simulations underestimate the dust vertical and long-range transport, compared with the satellite dust extinction profiles. After updating dust refractive indices and correcting for a bias in partitioning size-segregated emissions, both SW cooling and longwave (LW) warming of dust simulated by E3SMv1 are increased and agree better with other recent studies. The estimated net dust DRE of –0.42 Wm –2 represents a stronger cooling effect than the observationally based estimate –0.2 Wm –2 (–0.48 to +0.2), due to a smaller LW warming. Constrained by a global mean DAOD, model sensitivity studies of increasing horizontal and vertical resolution show strong influences on the simulated global dust burden and lifetime primarily through the change of dust dry deposition rate; there are also remarkable differences in simulated spatial distributions of DAOD, DRE, and deposition fluxes. Thus, constraining the global DAOD is insufficient for accurate representation of dust climate effects, especially in transitioning to higher- or variable-resolution ESMs. Better observational constraints of dust vertical profiles, dry deposition, size, and LW properties are needed.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Design of the Electron Ion Collider Electron Storage Ring SRF cavity

The Electron Ion Collider (EIC) under construction at Brookhaven National Laboratory is a high luminosity collider as the next major research facility for the nuclear physics community. Among the numerous RF subsystems in the EIC, the electron storage ring (ESR) fundamental RF cavities system is one of the most challenging. This system will handle a high beam current of up to 2.5A and replenish up to 10MW of beam power losses from synchrotron radiation and HOM. Variable coupling is required in the cavities due to the wide range of required total RF voltage and beam current combinations. In this paper, we will present the status of the design and future plans.

Guo, J.↗
DOE OSTI2022

SRF Levitation and Trapping of Nanoparticles

A proposal has been conceived to levitate and trap mesoscopic particles using radio frequency (RF) fields in a superconducting RF(SRF) cavity. Exploiting the intrinsic characteristics of an SRF cavity, this proposal aims at overcoming a major limit faced by state-of-the-art laser trapping techniques. The goal of the proposal is to establish a foundation to enable observation of quantum phenomena of an isolated mechanical oscillator interacting with microwave fields. An experiment supported by LDRD funding at JLab has started to address R&D issues relevant to these new research directions using existing SRF facilities at JLab. The success of this experiment would establish its groundbreaking relevance to quantum information science and technology, which may lead to applications in precision force measurement sensors, quantum memories, and alternative quantum computing implementations with promises for superior coherence characteristics and scalability well beyond the start-of-the-art. In this contribution, we will introduce the proposal and basic consideration of the experiment.

Geng, R. L.↗