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Wu, Genfa

Publications and source records attributed to Wu, Genfa.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Performance enhancement of medium temperature baked niobium SRF cavity by surface contamination removal

Medium temperature baking (300- 350 °C) enhances the quality factor of niobium superconducting radio frequency cavities. However, surface contamination introduced during vacuum furnace baking limits the quench field and may also degrade the quality factor of the cavity. To investigate this effect, a 1.3 GHz single-cell Nb cavity underwent mid-T baking, followed by a chemical treatment to remove the surface contaminants. Post-treatment measurements revealed a significant improvement in both the quality factor and the quench field.

Chouhan, Vijay [Fermilab] (ORCID:0000000282004931)↗
DOE OSTI2024

Successful cleanroom installation of PIP-II SSR2 coupler using robotic arm

To minimize the contamination of SRF cavities, remote installation techniques are needed during the installation of components. Recent work at Fermilab has been performed to begin the process of developing techniques for assembling cavities using robotics. Multiple alignment methods were prototyped including alignment and computer vision methods. Using a remotely controlled robotic arm, the alignment and installation of couplers have been successfully performed on prototype PIP-II SSR2 cavities in a cleanroom. The installation process will be shown to show to demonstrate the potential of future installations on other cavities and cavity ancillaries.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Status of the INFN LASA in-kind contribution to PIP-II project

The status of INFN LASA in-kind contribution to the PIP-II project at Fermilab is reported in this paper. The effort for the series production of the 38 INFN LASA designed, 5-cell cavities with beta 0.61 for the LB650 section of the linac commenced and the status of ongoing activities and major procurements is here conveyed. At the same time, preliminary tests on INFN LB650 cavity prototypes are progressing in order to optimize the complete preparation and qualification cycle. All cavities will be produced, and surface treated in industry to reach the unprecedented performances required, qualified through vertical cold test at state-of-the art infrastructures and delivered as installation ready at the string assembly site.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Towards Field Emission Free Cavity Processing and String Assembly at Fermilab

Cavities and cryomodules assembled at Fermilab have demonstrated unprecedented field emission (FE) free gradients. However, consistent FE-free performance is not guaranteed. Many lessons were learned, and continued vigilance is a must. In addition, several improvements have been identified to further push the state-of-the-art low particulate cavity processing and assembly at Fermilab. Those included the optimization of nitrogen flow, robotic-assisted assembly, and low-particulate fasteners. We share our latest results and vision for the future clean assemblies of cavities and cryomodule strings.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Robotic Systems integration for cleanroom SRF assembly at Fermilab

Superconducting Radio Frequency (SRF) cryomodule assembly is a critical process that demands the highest levels of contamination control in a cleanroom to ensure product quality and reliability. Within the cleanroom environment, human-driven activities remain the major source of uncontrolled particulate. Moreover, the precise manual alignment of components often exceeds expected timeframes, increasing the risk of particulate migration into the critical inner space of the SRF resonant cavity, and causing extended discomfort for workers. Automation comes as a natural solution to address these challenges. The goal of this activity is to set up and integrate a robotic system to support cavity coupler installation in the cleanroom environment. Initially, remote control of a 6-axis collaborative robot arm will be implemented as an introductory step towards automation in the cleanroom. Subsequently, the system will be further enhanced by integrating manipulation capabilities through an appropriate end-effector, and computer vision technology to enable accurate pose estimation. This comprehensive approach aims to achieve a fully automated and adaptable assembly process in the partially structured cleanroom environment, thereby enhancing efficiency and mitigating existing challenges for better product quality and workers safety.

42 ENGINEERING↗
DOE OSTI2023

Flux Expulsion Studies of Niobium Material of 650 MHz Cavities for PIP-II

Two different vendors supplied the niobium sheet material for PIP-II 5-cell 650 MHz cavities, which was characterized by multiple different ASTM sizes. Cavities subsequently fabricated from these sheets were heat-treated at various temperatures, then the cavities’ flux-expulsion performance was measured. Where the initial measurements of vendor O materials showed that nearly all flux remained trapped despite a high thermal gradient, 900C heat treatment subsequently improved the flux expulsion to an acceptable rate. Understanding and characterizing vendor O materials in this way is key for upcoming and future projects planning to employ niobium sheet from this supplier.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Medium Temperature Furnace Baking of Low-beta 650 MHz Five-cell Cavities

Medium Temperature baking of low beta 650 MHz cavities was conducted in a UHV furnace. A systematic study of cavity surface resistance components, residual and BCS, was conducted, including analyzing surface resistance due to trapped magnetic flux. Cavities showed an average 4.5 nano-ohm surface resistance at 17 MV/m under 2 K, which meets PIP-II specifications with a 40% margin. The results provided helpful information for the PIP-II project to optimize the cavity processing recipe for cryomodule application. The results were compared to the 1.3 GHz cavity that received a similar furnace baking.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Latest Development of Electropolishing Optimization for 650 MHz Cavity

Electropolishing (EP) of 1.3 GHz niobium (Nb) superconducting RF cavities is conducted to achieve a desired smooth and contaminant-free surface that yields good RF performance. Achieving a smooth surface of a large-sized elliptical cavity with the standard EP conditions was found to be challenging. This work aimed to conduct a systematic parametric EP study to understand the effects of various EP parameters on the surface of 650 MHz cavities used in PIP-II linac. Parameters optimized in this study provided a smooth surface of the cavities. The electropolished cavities met the baseline requirement of field gradient and qualified for further surface treatment to improve the cavity quality factor.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

The Evaluation of Mechanical Properties of LB650 Cavities

The 650 MHz cavities have a stronger requirement of niobium mechanical properties because of the geometric shape of the cavity due to reduced beta. The mechanical property of the niobium half-cell was measured following various heat treatments. The 5-cell cavities were tested in a controlled drop test fashion and the real-world road test. The result showed that the 900C heat treatment was compatible with cavity handling and transportation during production. The test provides the bases of the transportation specification and shipping container design guidelines.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Beam Commissioning and Integrated Test of the PIP-II Injector Test Facility

The PIP-II Injector Test (PIP2IT) facility is a near-complete low energy portion of the Superconducting PIP-II linac driver. PIP2IT comprises the warm front end and the first two PIP-II superconducting cryomodules. PIP2IT is designed to accelerate a 2 mA H⁻ beam to an energy of 20 MeV. The facility serves as a testbed for a number of advanced technologies required to operate PIP-II and provides an opportunity to gain experience with commissioning of the superconducting linac, significantly reducing project technical risks. Some PIP2IT components are contributions from international partners, who also lend their expertise to the accelerator project. The project has been successfully commissioned with the beam in 2021, demonstrating the performance required for the LBNF/DUNE. In this paper, we describe the facility and its critical systems. We discuss our experience with the integrated testing and beam commissioning of PIP2IT, and present commissioning results. This important milestone ushers in a new era at Fermilab of proton beam delivery using superconducting radio-frequency accelerators.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

LCLS-II-HE Cryomodule Testing at Fermilab

22 Linac Coherent Light Source II (LCLS-II) cryomodules were successfully tested at the Cryomodule Test Facility (CMTF) at Fermilab. Following the completion of the LCLS-II testing program, CMTF has shifted to testing cryomodules for the LCLS-II High Energy upgrade (LCLS-II-HE). The first LCLS-II-HE cryomodule, the verification cryomodule (vCM), was successfully tested and verified the readiness of LCLS-II-HE cryomodule testing at CMTF, and production cryomodule testing has begun. Presented here are the production cryomodule test acceptance criteria, testing plan, and cryomodule test results so far.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Design, Manufacturing, Assembly, Testing, and Lessons Learned of the Prototype 650 MHz Couplers

Six 650 MHz high-power couplers will be integrated into the prototype High Beta 650 MHz (HB650) cryomodule for the PIP-II project at Fermilab. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life-cycle, including manufacturing, assembly, testing, conditioning and the lessons learned at each stage.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Proton Improvement Plan – II: Overview of Progress in the Construction

The Proton Improvement Plan II (PIP-II) project is an essential upgrade to Fermilab’s particle accelerator complex to enable the world’s most intense neutrino beam for LBNF/DUNE and a broad particle physics program for many decades to come. PIP-II will deliver 1.2 MW of proton beam power from the Main Injector, upgradeable to multi-MW capability. The central element of PIP-II is an 800 MeV linac, which comprises a room temperature front end followed by an SRF accelerator. The front end has been constructed and operated with (pulsed & CW) beam in the PIP-II Injector Test facility (PIP2IT). The SRF accelerator consists of five different types of cavities/cryomodules, including Half Wave Resonators (HWR), Single Spoke and elliptical resonators operating at state-of-the-art parameters. The first two PIP-II cryomodules, HWR and Single Spoke Resonator 1 (SSR1) are installed in PIP2IT and have accelerated beam to 17 MeV. PIP-II is the first U.S. accelerator project that will be constructed with significant contributions from international partners, including India, Italy, France, United Kingdom and Poland. The project was recently baselined, and site construction is underway

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Toward Qualifications of HB and LB 650 MHz Cavities for the Prototype Cryomodules for the PIP-II Project

High-beta (HB) and low-beta (LB) 650 MHz cryomodules are key components of the Proton Improvement Plan II (PIP-II) project. In this contribution we present the results of several 5-cell HB650 cavities that have been processed and tested with the purpose of qualifying them for the prototype cryomodule assembly, which will take place later this year. We also present the first results obtained in LB650 single-cell cavities process optimization. Taking advantage of their very similar geometry, we are also analyzing the effect of different surface treatments in FRIB’s 5-cell medium-beta 644MHz cavities. Cavities processed with N-doping and mid-T baking showed very promising results in term of both Q-factors and accelerating gradient for these low-beta structures.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

STC Qualification Tests of PIP-II HB650 Cavities

Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q₀ > 3.3 · 10^{z}EhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. The Fermilab Spoke Test Cryostat (STC) has been upgraded to accommodate testing of 650 MHz cavities. Commissioning of upgraded STC has been reported at SRF’19 conference. In this paper we present results of testing of the prototype HB650 cavity in upgraded STC facility. We characterize cavity performance and qualify it for the prototype HB650 cryomodule assembly.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Design of the 650 MHz High Beta Prototype Cryomodule for PIP-II at Fermilab

The Proton Improvement Plan II (PIP-II) is the first U.S. accelerator project that will have significant contributions from international partners. The prototype High Beta 650 MHz cryomodule (pHB650 CM) is designed by an integrated design team, consisting of Fermilab (USA), CEA (France), UKRI-STFC (UK), and RRCAT (India). The manufacturing & assembly of this prototype cryomodule will be done at Fermilab, whereas the production cryomodules will be manufactured and/or assembled by UKRI-STFC, RRCAT, or Fermilab. Similar to the prototype Single Spoke Resonator 1 cryomodule (pSSR1 CM), this cryomodule is based on a strong-back at room temperature supporting the coldmass. The pSSR1 CM led to significant lessons being learnt on the design, procurement, and assembly processes. These lessons were incorporated into the design and processes for the pHB650 CM. Amongst many challenges faced, the main challenges of the pHB650 CM design were to make the cryomodule compatible to overseas transportation and to design components that can be procured in USA, Europe, and India.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Test Results of the Prototype SSR1 Cryomodule for PIP-II at Fermilab

A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses has been successfully assembled and cold tested in the framework of PIP-II project at Fermilab. The performance of cavities and focusing lenses along with test results of other cryomodule’s key parameters are presented in this contribution.

43 PARTICLE ACCELERATORS↗