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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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26 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

The Relation Between Field Flatness and the Passband Frequency in the Elliptical Cavities

A technique that predicts the field flatness of the operating pi-mode based on the passband frequency is highly desirable when the direct measurement of the field is not available. Such a technique was developed for the SNS-PPU cavity, a 6-cell SRF cavity whose field flatness is important for cold operation. In this paper, we will present the theory on the relations between field profile and passband frequencies of the arbitrary deformed cavities, the simulation studies, and comparison with the experimental measurements.

Park, G. -T.↗
DOE OSTI2026

Python-EPICS RF Conditioning Automatic Control System at the Spallation Neutron Source

The RF Test Facility (RFTF) at the Spallation Neutron Source (SNS) is used for the conditioning of RF compo-nents such as ceramic vacuum windows and power cou-plers prior to their installation in the H- ion linear accel-erator. This process exposes components to high-power RF fields and thermal cycling to improve performance and remove surface impurities. To automate and optimize this process, a Python-based EPICS control system was developed alongside targeted hardware upgrades. The system enables real-time monitoring and control of RF power levels, temperature, and vacuum pressure. A user-friendly graphical interface was implemented using CS-Studio (Phoebus), allowing operators to adjust parameters and collect data efficiently. The system integrates a High-Power Protection Module (HPM) for interlocks based on vacuum and arc detection, ensuring safe operation. These upgrades have significantly improved the efficiency, accuracy, and safety of RF conditioning at the SNS RFTF. This paper describes the updated RF conditioning sys-tem, highlighting the software and hardware develop-ments and their application in support of the Proton Pow-er Upgrade (PPU) project.

Lee, Sung-Woo [ORNL] (ORCID:000000030915835X)↗
DOE OSTI2022

Status of SNS Proton Power Upgrade SRF Cavities Production Qualification

The Pro­ton Power Up­grade pro­ject at Oak Ridge Na­tional Lab’s Spal­la­tion Neu­tron Source (SNS PPU) cur­rently being con­structed will dou­ble the pro­ton beam power from 1.4 to 2.8 MW by adding 7 ad­di­tional cry­omod­ules, each con­tains four six-cell high beta (\beta = 0.81) su­per­con­duct­ing radio fre­quency cav­i­ties. The cav­i­ties were built by Re­search In­stru­ments, Ger­many, with all the cav­ity pro­cess­ing done at the ven­dor site, in­clud­ing elec­trop­o­l­ish­ing as the final ac­tive chem­istry step. All 28 cav­i­ties needed for 7 cry­omod­ules were de­liv­ered to Jef­fer­son Lab, ready to be tested. The cryo­genic RF qual­i­fi­ca­tions and he­lium ves­sel weld­ing were done at Jef­fer­son Lab. The per­for­mance largely ex­ceed the re­quire­ments, and greatly ex­ceeded the per­for­mance of the orig­i­nal SNS cav­ity pro­duc­tion se­ries. Here, we pre­sent the sum­mary of RF test on pro­duc­tion cav­i­ties to this date.

Dhakal, P.↗
DOE OSTI2021

Status of SNS Proton Power Upgrade SRF Cavities Production Qualification

The Pro­ton Power Up­grade pro­ject at Oak Ridge Na­tional Lab’s Spal­la­tion Neu­tron Source (SNS PPU) cur­rently being con­structed will dou­ble the pro­ton beam power from 1.4 to 2.8 MW by adding 7 ad­di­tional cry­omod­ules, each con­tains four six-cell high beta (\beta = 0.81) su­per­con­duct­ing radio fre­quency cav­i­ties. The cav­i­ties were built by Re­search In­stru­ments, Ger­many, with all the cav­ity pro­cess­ing done at the ven­dor site, in­clud­ing elec­trop­o­l­ish­ing as the final ac­tive chem­istry step. All 28 cav­i­ties needed for 7 cry­omod­ules were de­liv­ered to Jef­fer­son Lab, ready to be tested. The cryo­genic RF qual­i­fi­ca­tions and he­lium ves­sel weld­ing were done at Jef­fer­son Lab. The per­for­mance largely ex­ceed the re­quire­ments, and greatly ex­ceeded the per­for­mance of the orig­i­nal SNS cav­ity pro­duc­tion se­ries. Here, we pre­sent the sum­mary of RF test on pro­duc­tion cav­i­ties to this date.

Dhakal, P.↗
DOE OSTI2020

Shielding development for the VENUS imaging instrument

VENUS is an imaging instrument that will use a broad range of neutron wavelengths, from epithermal to cold, will include enhanced contrast mechanisms, and will offer novel energy-selective imaging techniques that directly connect the structures, properties, and function of complex engineering materials and systems to reveal practical and fundamental answers about their real-world performance. The instrument is to be built at SNS beam line 10 and will face the decoupled poisoned hydrogen moderator. The driving cost for the instrument is the beam line and instrument cave shielding. Initial scoping analyses were performed to estimate thickness and composition of shielding materials for the instrument cave and beam line. In light of the upcoming Proton Power Upgrade (PPU) project, these transport analyses were performed for proton beam on target at 1.3 GeV and 2 MW.

Popova, Irina I.↗
DOE OSTI2023

Design and fabrication of the waveguide Iris couplers for the Spallation Neutron Source drift tube linac

The Spallation Neutron Source (SNS) employs six cavities in the Drift Tube Linac (DTL) section to accelerate the H- ion beam to 87MeV. Each cavity is energized by a 2.5MW peak power klystron at 402.5MHz using rapid tapered waveguide iris couplers. All six original iris couplers have been in operation without replacement for over two decades. The increased RF power demands of the Proton Power Upgrade (PPU) project and operational problems, including arcing, temperature excursions, and vacuum bursts, have prompted the development of new iris coupler spares. The original iris couplers were made of GlidCop material, which is known to be mechanically strong and thermally stable, but is porous, expensive, and difficult to use in fabrication. To overcome these problems, the new spare couplers use Oxygen-Free Copper (OFC) and stainless steel (SS). This paper will discuss the mechanical, thermal and RF design, as well as challenges in the final coupler fabrication.

Lee, Sung-Woo↗
DOE OSTI2023

Control Systems Design for STS Accelerator

The Second Target Station (STS) Project will expand the capabilities of the existing Spallation Neutron Source (SNS), with a suite of neutron instruments optimized for long wavelengths. A new accelerator transport line will be built to deliver one out of four SNS pulses to the new target station. The Integrated Control Systems (ICS) will provide remote control, monitoring, OPI, alarms, and archivers for the accelerator systems, such as magnets power supply, vacuum devices, and beam instrumentation. The ICS will upgrade the existing Linac LLRF controls to allow independent operation of the FTS and STS and support different power levels of the FTS and STS proton beam. The ICS accelerator controls are in the phase of preliminary design for the control systems of magnet power supply, vacuum, LLRF, Timing, Machine protection system (MPS), and computing and machine network. The accelerator control systems build upon the existing SNS Machine Control systems, use the SNS standard hardware and EPICS software, and take full advantage of the performance gains delivered by the PPU Project at SNS.

Yan, Jay↗
DOE OSTI2024

Calibration of the analog beam-signal hardware for the credited engineered beam power limit system at the Proton Power Upgrade Project at the Spallation Neutron Source

A programmable signal processor-based credited safety control that calculates pulsed beam power based on beam kinetic energy and charge was designed as part of the Proton Power Upgrade (PPU) project at the Spallation Neutron Source (SNS). The system must reliably shut off the beam if the average power exceeds 2.145 MW averaging over 60 seconds. System calibration requires pedigree in measurements, calibration setup, and calculations. This paper discusses the calibration of the analog beam signal components up to and including the Analog Digital Convertors (ADCs) for implementation into the Safety Programmable Logic Controllers (PLCs) and Field Programmable Gate Arrays (FPGAs).

Bobrek, Miljko↗