Engineering Papers⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3383766

Beam halo formation with different cathode distributions

Neththikumara, I. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Gamage, B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Deitrick, K. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Sereno, N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Rimmer, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Setiniyaz, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Satogata, T. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)]·Wang, E. [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Bergan, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Wang, N. [Cornell Univ., Ithaca, NY (United States)]
View original source ↗Read source document ↗Export metadata ↓

Abstract

Beam halo refers to the low-density distribution of particles extending beyond the beam core, and its generation and mitigation are important topics in particle accelerator design. Effective mitigation of beam halo is essential for the cooler design based on Energy Recovery Linac (ERL), which must deliver an electron beam with average beam current of 100 mA and a charge 1 nC per bunch. In the ERL injector and booster linacs, space charge effects are stronger due to relatively low beam energy (6 MeV). Additionally, the longer bunch length of approximately 100 ps in this regime vs the RF period of 5.08 ns makes the formation of beam halos more likely. Therefore, effective collimation of beam halo is critical to maintaining the required beam parameters. To design an effective collimation scheme, several halo distributions were generated at the cathode and used to study halo formation within the injector-merger. This paper presents different halo distributions and halo formation, providing insights on halo collimation strategy.

Explore related subjects

Accelerator Physicsmc5-beam-dynamics-and-em-fields - MC5 – Beam Dynamics and EM Fields

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Neththikumara, I. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Gamage, B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Deitrick, K. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Sereno, N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Rimmer, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Setiniyaz, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Satogata, T. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)], Wang, E. [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Bergan, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Wang, N. [Cornell Univ., Ithaca, NY (United States)]. 2026-01-01. Beam halo formation with different cathode distributions. https://doi.org/10.18429/jacow-napac2025-tup015

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Transverse BBU Suppression with Feedback for Energy-Recovery Linacs

The Electron–Ion Collider (EIC) achieves its design luminosity by cooling the ion beam with a high-current electron beam generated in an energy-recovery linac (ERL). The baseline ERL lattice employs a BNL five-cell cavity that is frequency-scaled to 197 MHz, 591 MHz, and 1.773 GHz, raising concerns about multibunch beam-breakup (BBU) instabilities. Threshold currents for each frequency option are established with two independent BBU tracking codes, providing cross-validated operating margins that guide cavity selection. To further increase the current limit, we incorporate a digital transverse feedback (FB) system that targets the dominant higher-order modes (HOMs). Simulations show the FB raises the BBU threshold by roughly an order of magnitude: power-spectral-density analysis of the beam centroid at the linac exit confirms strong suppression of the aliased HOM peak, although some spectral growth appears at secondary frequencies. This combined study quantifies baseline BBU limits, demonstrates effective active mitigation, and charts a practical path toward robust, high-current operation of the EIC ERL.

Accelerator Physics↗
DOE OSTI2026

A reactive ferroelectric tuner for microphonics compensation

Jefferson Lab (JLab) is actively pursuing an extensive research program focused on developing advanced Nb₃Sn superconducting technology for particle accel-eration. Due to the brittle nature of Nb₃Sn coatings, a Ferroelectric Tuner (FRT) currently represents the most viable approach for microphonics compensation in these next-generation cavities. We suggest a novel, fast-responding FRT integrated directly into the main coupler, eliminating the need for an additional RF port. Leveraging a unique RF design based on a magic-T configuration, this advanced FRT will enable micro-phonics compensation in the ±30 Hz range without undesirable changes to the external quality factor.

Accelerator Physics↗
DOE OSTI2026

Lifetime extension of legacy CEBAF LLRF hardware

A significant portion of the Low-Level Radio Frequency (LLRF) hardware in Jefferson Lab’s CEBAF is from the original construction of the facility using 1980’s CAMAC technology. Of the fifty-three zones in CEBAF, thirty-six of them are legacy hardware. The age of the legacy system has led to difficulties in maintaining the hardware due to parts going obsolete without suitable drop in replacements. Continued operation of the legacy system is required as the installation of LLRF 3.0 systems is costly and cannot be completed in a short period of time with the available resources. The most pressing failure in the legacy system was a failing buffer card, which is responsible for communication between the EPICs network and individual RF control modules. A new buffer card was designed as a transparent, drop in, replacement so that upgrades are simply a matter of swapping the existing legacy hardware. This buffer card upgrades a single point failure component and promises to extend the operable lifetime of CEBAF’s legacy systems.

Accelerator Physics↗