arXiv subjects

D. Passarelli

Publications and source records attributed to D. Passarelli.

12 recordsLinked to original sources

arXiv2026

Heat load measurements for the PIP-II pHB650 cryomodule

Phase-3 testing of the pHB650 cryomodule at the PIP-II Injector Test Facility was conducted to evaluate the effectiveness of heat load mitigations performed after earlier phases of testing and to continue pinpointing any sources of unexpectedly high heat loads.. The programme measured HTTS, LTTS, and 2 K isothermal/non-isothermal loads under "standard", "linac", and "simulated dynamic" operating modes, recording data both inside the cryomodule and across the bayonet can circuits. Thermal-acoustic oscillations were eliminated by replacing the original G10 cooldown-valve stem with a stainless-steel stem fitted with wipers. A newly developed Python script automated acquisition of ACNET data, performed real-time heat-load calculations, and generated plots and tables that were posted to the electronic logbook within minutes, vastly reducing manual effort and accelerating feedback between SRF and cryogenics teams. Analysis showed that JT heat-exchanger effectiveness and temperature stratification in the two-phase and relief piping strongly influence the observed loads and helped isolate sources of excess heat. The campaign demonstrates that rigorous pre-test planning, real-time diagnostics, and automated reporting can improve both accuracy and efficiency, providing a template for future PIP-II cryomodule tests and for implementing targeted heat-load mitigations.

physics.acc-ph↗

arXiv2024

Cold Test Results of Pre-Production PIP-II SSR2 Cavities with High-Power Couplers in the Fermilab Spoke Test Cryostat

As part of the PIP-II project at Fermilab, a pre-production cryomodule featuring 325 MHz Single Spoke Resonator type 2 (SSR2) superconducting RF cavities is under construction. These SSR2 cavities are fabricated by industry partners and undergo initial cold testing at our collaborating institution, IJCLab in France, utilizing low-power coupler. Subsequently, the cavities are subjected to final qualification at Fermilab, complete with tuner and high-power coupler assemblies. This paper provides an overview of the ongoing efforts dedicated to high-power testing of jacketed SSR2 cavities in the Spoke Test Cryostat (STC) at Fermilab. Performance parameters obtained from these tests are presented, offering valuable insights into the cavities operational characteristics and readiness for integration into the PIP-II cryomodule.

physics.acc-ph↗

arXiv2024

Impact of Solenoid Induced Residual Magnetic Fields on The Prototype SSR1 CM Performance

A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses was successfully assembled, cold tested, and accelerated beam in the framework of the PIP-II project at Fermilab. The impact of induced residual magnetic fields from the solenoids on performance of cavities is presented in this contribution. In addition, design optimizations for the production cryomodules as a result of this impact are highlighted.

physics.acc-ph↗

arXiv2023

PIII Project Overview and Status

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 superconducting radio frequency (SRF) linac, which comprises a room temperature front end followed by an SRF section. The SRF section consists of five different flavors of cavities/cryomodules, including Half Wave Resonators (HWR), Single Spoke and elliptical resonators operating at, or above, state-of-the-art parameters. The first two PIP-II cryomodules, Half Wave Resonator (HWR) and Single Spoke Resonator 1 (SSR1) were installed in the PIP-II Injector Test facility (PIP2IT) and have accelerated beam to above 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 baselined in April 2022, and the construction phase is underway.

physics.acc-ph↗

arXiv2023

Final Design of the Production SSR1 Cryomodule for PIP-II Project at Fermilab

This contribution reports the design of the production Single Spoke Resonator Type 1 Cryomodule (SSR1 CM) for the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1), the prototype High Beta 650 MHz (pHB650), and preproduction Single Spoke Resonator Type 2 (ppSSR2) cryomodules is the baseline of the present design. The focus of this contribution is on the results of calculations and finite element analyses performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield.

physics.acc-ph↗

arXiv2023

PIP-II SSR2 Cavities Fabrication and Processing Experience

The Proton Improvement Plan-II (PIP-II [1]) linac will include 35 Single Spoke Resonators type 2 (SSR2). A preproduction SSR2 cryomodule will contain 5 jacketed cavities. Several units are already manufactured and prepared for cold testing. In this work, data collected from the fabrication, processing and preparation of the cavities will be presented and the improvements implemented after the completion of the first unit will be highlighted.

physics.acc-ph↗

arXiv2023

Design, Manufacturing, Assembly, and Lessons Learned of the Pre-production 325 MHz Couplers for the PIP-II Project at Fermilab

Five 325 MHz high-power couplers will be integrated into the pre-production Single Spoke Resonator Type-II (ppSSR2) cryomodule for the PIP-II project at Fermilab. Couplers were procured by both Fermilab and IJCLAB for this effort. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life cycle, including design, manufacturing, and assembly, along with the lessons learned at each stage.

physics.acc-ph↗

arXiv2022

Beamline Volume Relief Analysis for the PIP-II SSR2 Cryomodule at Fermilab

The beam volume of the Pre-Production Single Spoke Resonator type 2 (ppSSR2) cryomodule [1] for the Proton Improvement Plan-II (PIP-II) [2] project will be protected against over-pressurization using a burst disk. This contribution focuses on the analysis of the relief of such trapped volume during a catastrophic scenario with multiple systems failures. An analytical model, able to predict the pressure in the beam volume depending of the various boundary conditions, has been developed and will be presented along with the results.

physics.acc-ph↗

arXiv2022

Fabrication experience of the pre-production PIP-II SSR2 cavities at Fermilab

The Proton Improvement Plan-II (PIP-II, [1]) linac will include 35 Single Spoke Resonators type 2 (SSR2). A total of eight pre-production SSR2 jacketed cavities will be procured and five installed in the first pre-production cryomodule. The mechanical design of the jacketed cavity has been finalized and it will be presented in this paper along with fabrication and processing experience. The importance of interfaces, quality controls and procurement aspects in the design phase will be remarked as well as lessons learned during the fabrication process. Furthermore, development studies will be presented together with other design validation tests.

physics.acc-ph↗

arXiv2022

Niobium to Titanium Electron Beam Welding for SRF Cavities

Titanium and niobium are the main materials used for the fabrication of Superconducting Radio Frequency (SRF) cavities. These two metals are usually joined , using various welding techniques, using a third material in between. This contribution focuses on the development of an innovative electron beam welding technique capable of producing a strong bond between these two different materials. Several samples are produced and tested to assess the mechanical strength at room and cryogenic temperature as well as the composition of the resulting welded joint. Also, the first units of the Single Spoke Resonator type 2 (SSR2) cavities for the Proton Improvement Plan-II (PIP-II [1]) have been fabricated joining directly various grades of titanium to niobium and results gathered through the fabrication will be reported.

physics.acc-ph↗

arXiv2022

Application Of The ASME Boiler And Pressure Vessel Code In The Design Of SSR Cryomodule Beamlines For PIP-II Project At Fermilab

This contribution reports the design of the main components used to interconnect SRF cavities and superconducting focusing lenses in the SSR Cryomodule beamlines, developed in the framework of the PIP-II project at Fermilab. The focus of the present contribution is on the design and testing of the edge-welded bellows according to ASME Boiler and Pressure Vessel Code. The activities performed to qualify the bellows to be assembled in cleanroom, for operation in high vacuum, cryogenic environments, and their characterization from magnetic standpoint, will also be presented.

physics.acc-ph↗

arXiv2022

Final Design Of The Pre-production SSR2 Cryomodule For PIP-II Project At Fermilab

The present contribution reports the design of the pre-production Single Spoke Resonator Type 2 Cryomodule (ppSSR2 CM), developed in the framework of the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1) and the prototype High Beta 650 MHz (pHB650) cryomodules is the baseline of the current design, which paves the way for production SSR1 and SSR2 cryomodules for the PIP-II linac. The focus of this contribution is on the results of calculations and finite element analysis performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield.

physics.acc-ph↗