Ongoing studies at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) seek to understand and model bunch dynamics in a high-power LINAC front-end. The BTF has recently been upgraded with a reconfiguration from a U-shaped line to a Straight line. We report the current state of model benchmarking, with a focus on RMS beam sizes within the FODO line. The beam measurement is obtained via three camera/screen pairs in the FODO line. This presentation discusses the methodology and results of this measurement.

Measuring longitudinal beam parameters is key for the operation and development of high-intensity linear accelerators but is notoriously difficult for ion beams at non-relativistic energies. The Bunch Shape Monitor (BSM) is a device used for measuring the longitudinal bunch distribution in a hadron linac. RadiaBeam has developed a BSM prototype with enhanced performance, integrating several key innovations. Firstly, to improve the collection efficiency, we introduced a focusing field between the target wire and the entrance slit. Secondly, we implemented a novel design of the RF deflector to enhance beam linearity. Finally, the design was enriched by incorporating a mechanism that allows moving both the wire and deflector cavity enabling the functionality of transverse profile measurements. In this paper, we present the process of fabricating, assembling, and beam tests of the BSM prototype at the SNS facility.

Ongoing studies at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) seek to understand and model bunch dynamics in a high-power LINAC front-end. The BTF has recently been upgraded with a reconfiguration from a U-shaped line to a Straight line. We report the current state of model benchmarking, with a focus on RMS beam sizes within the FODO line. The beam measurement is obtained via three camera/screen pairs in the FODO line. This presentation discusses the methodology and results of this measurement.

Laser wire has been used for nonintrusive profile and emittance measurements of operational hydrogen ion (H-) beam at the SNS linac. In this talk, we will describe the following recent developments in the laser wire system. 1) An upgraded light source and laser transport line which enables novel measurement capabilities including longitudinal profile measurement and high-energy proton beam extraction over potentially an entire macropulse. 2) A dual-detector emittance measurement scheme that boosted the dynamic range by an order of magnitude. 3) Design and implementation laser-wire-based nonintrusive longitudinal phase space measurement system.

The WS superconducting systems are based on scintillator detectors and wavelength shifting fibers are mounted on the beam pipe. The detectors are coupled to long haul optical fibers, which carry the signals to custom front end electronics sitting in controls racks at the surface. The acquisition chain have been characterized at IHEP (Protvino), CERN PSB, COSY Juelich and SNS before installation in the ESS tunnel. The beam test results of this system design, differing from the standard approach where photomultipliers are coupled to the scintillator will be presented.

A Laser Assisted Charge Exchange (LACE) injection in the Spallation Neutron Source (SNS) is under development. By utilizing powerful lasers and magnetic fields, electrons are stripped out of the H- beam without foils. Such a process avoids any foil-based charge exchange injection problems, such as foil degradation and beam loss, especially for future multi-megawatt power beams. Proof-of-principle of LACE has been experimentally demonstrated in the SNS in a transport line. Integration of the LACE injection into the SNS accumulator ring is in progress. In this paper, we present preliminary results of optics design and beam dynamics study.

The Spallation Neutron Source (SNS) Beam Test Facility (BTF) supports the study of beam dynamics in the front end of a high power LINAC. The BTF combines a replica of the SNS front end, including nearly-identical ion source, RFQ and MEBT, with extensive phase space diagnostics and a FODO transport line. Diagnostic capabilities include direct measurement of 6D phase space distribution and detection of halo distributions to a sensitivity of greater than one part-per-million. The goal of on-going BTF studies is to demonstrate accurate particle-in-cell modeling of halo growth and evolution by leveraging unprecedented accuracy in the description of the initial beam distribution. This work is motivated by operational experience at the SNS, which currently operates with beam loss that cannot be described by any model. This paper summarizes progress in the BTF beam study program as well as diagnostics development and recent upgrades to the beamline configuration.

We study possibility of laser assisted charge exchange injection at the SNS. The realistic injection of LACE injection and accumulation into the Ring of SNS is considered. The design of stripping magnets at the injection area is one of the most challenging problems toward operational scheme of LACE at the SNS. Basic requirements and needed parameters of stripping magnets are studied. Based on this study the possibility of real stripping magnet design is considered.