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HomeEvents ICFA Mini-Workshop “Coherent Electron Cooling – Theory, Simulations and Experiment”, July 2019, at Stony Brook University

CASE/C-AD seminars for graduate students and postdocs

 

 

Goals

The main goal of the CASE seminars is to provide a venue where grad students and postdocs can get together, learn about each others' research and open their scientific horizons in general. The seminars will be a mix of student’s and postdoc’s presentations of their recent results, dry runs of conference presentations, reviews of journal articles, visits to BNL accelerators and testing areas and occasional invited presentations by senior scientists from BNL and SBU.

Venue

The seminars are typically held every other Tuesday, from 4:30 to 5:30 pm in the RHIC Main Control Room meeting area (bldg. 911B, 2nd floor) at BNL.

Seminars

Season 2019

UPCOMING SEMINARS

Abstract: We have developed an intrinsic resonance free circular electron accelerator. This lattice could be placed in the existing RHIC tunnel and accelerate electrons from 400 MeV to 18 GeV avoiding all major polarization loss usual in such machines.
Abstract: Crab crossing is an essential mechanism for high-luminosity particle colliders. Several future particle colliders (HL-LHC, EIC, FCC-hh) incorporate crab cavities in their design. The possibilities offered by crab cavities are multiple. Firstly, to reestablish head-on collisions, which maximize the colliding bunches overlap and consequently the peak luminosity. Equally important, crabs provide another mechanism for luminosity levelling by adjusting the crabbing angle as bunches depopulate with every collision. In addition, crabs allow implementing the crab kissing technique which reduces the pile-up density. This talk will discuss the different crab operation modalities and their impact on experimental data quality, present the main motivation behind the adoption of crab cavities by different colliders and provide an overview of the cavity designs being considered for the crabbing systems of these future colliders.


PAST SEMINARS

Abstract: The capability of accelerating a polarized 3He ion beam in RHIC would provide an effective polarized neutron beam for the study of new high-energy QCD studies of nucleon structure. This development would be particularly beneficial for the future plans of an Electron Ion Collider, which could use a polarized 3He ion beam to probe the spin structure of the neutron. The proposed polarized 3He ion source is based on the Electron Beam Ion Source (EBIS) currently in operation at Brookhaven National Laboratory. 3He gas would be polarized within the 5 T field of the EBIS solenoid via Metastability Exchange Optical Pumping (MEOP) and then pulsed into the EBIS vacuum and drift tube system where the 3He will be ionized by the 10 Amp electron beam. The goal of the polarized 3He ion source is to achieve 2.5 x 10^11 3He++/pulse at 70% polarization. An upgrade of the EBIS is currently underway.


Season coordinator: Dr. Silvia Verdú-Andrés.

Season 2018

  • April 18, 2018: Thermal studies on cryogenic components for the electron-ion collider at Brookhaven National Laboratory by Dhananjay Ravikumar (BNL/SBU).


Season coordinator: Dr. Silvia Verdú-Andrés.

Season 2017

Abstract: Coherent electron Cooling (CeC) is an advanced method of beam cooling which is based on electrostatic interactions between electron and ion beams amplified by a high-gain Free Electron Laser (FEL). This promising method would significantly reduce cooling time of a hadron beam compared to the other known techniques. A 15 MeV CW SRF accelerator has been commissioned at Brookhaven National Laboratory to test the CeC concept. In this talk, I will describe our experience with this system with focus on unusual phenomena, such as multipacting in the SRF gun, alongside with the simulation results, and discuss our plans for the wakefields and beam dynamics simulations.
  • August 17, 2017: Social meet-up.
Abstract: The commissioning of the Coherent electron Cooling (CeC) proof of principle experiment is under way at the Relativistic Heavy Ion Collider (RHIC). A 112 MHz Superconducting Radio Frequency (SRF) photo-emission gun is used to generate the electron beam for this experiment. In this presentation I report selected results of experimental emittance measurements and compare them with our simulations. After that, phase space reconstruction by tomography method is discussed.
Abstract: The control systems of the Collider-Accelerator Department (C-AD) at Brookhaven National Laboratory (BNL) is a complex system consisting of approximately 1.5 million control points. Instances of C-AD control systems are applied in the Linear Accelerator (Linac), Electron Beam Ion Source (EBIS), Tandem Van de Graff pre-accelerators, the Booster accelerator, Alternating Gradient Synchrotron (AGS), and the Relativistic Heavy Ion Collider (RHIC). Thus, its performance has a crucial impact over the whole accelerator suite. In this presentation, we discuss several projects related to the RHIC control system, which is a typical implementation of the C-AD control system, aiming to improve its performance.
Abstract: Brookhaven National Laboratory (BNL) has proposed to build an Electron Ion Collider (EIC) as an upgrade to the existing Relativistic Heavy Ion Collider (RHIC). A part of the new design is to use Superconducting Radio Frequency (SRF) cavities for acceleration, which sit in a bath of superfluid Helium at a temperature of 2 K. SRF cavities designed for the BNL EIC create a standing Electromagnetic wave, oscillating at a fundamental frequency of 647 MHz. Interaction of the charged particle beam with the EM field in the cavity creates Higher Order Modes (HOM) of oscillation which have adverse effects on the beam if it is allowed to propagate down the beam tube. HOM waveguides are thus designed to remove this excess energy which is then damped at room temperature. As a result, these waveguides provide a direct thermal link between room temperature and the superconducting cavities adding a static thermal load. The EM wave propagating through the warmer sections of the waveguide creates and additional dynamic thermal load. This study aims to estimate these thermal loads, map temperature distributions on the waveguide and come up with an efficient design to manage heat flow such that the load on the 2 K cryogenic system is as low as possible.
Abstract: Multipacting is a complex phenomenon in which a large number of electrons build up within the cavity volume leading to the undesirable RF power absorption. The 112 MHz Superconducting Photo-electron Gun used for the Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment encountered several multipacting zones during the Run'16. In order to understand performance limitations for the next run, a series of numerical and analytical calculations was performed. Methods for multipacting calculations and the results obtained for the SRF Gun will be presented and discussed.
Abstract: Beam breakup instability occurs in recirculating accelerators when beam bunches interact with higher order modes (HOMs) in accelerating cavities. BBU is an important limiting factor to the maximum achievable current in an ERL. Cornell and BNL are currently designing CBETA, a prototype accelerator for future eRHIC upgrade. To find out the threshold current of CBETA due to BBU instability, beam-tracking simulations were run using Bmad software. In this talk I will talk about basic BBU theory, how Bmad models BBU effects, and potential ways to increase the threshold current.


Season coordinator: Dr. Silvia Verdú-Andrés.

Season 2016

Abstract: The problem of nuclear waste continues to raise lots of concerns of whether the nuclear power should continue when the issue of how to deal with its waste has not yet been resolved. After reviewing the history of the nuclear waste problem in the United States of America and other countries, the question of how to remedy this problem is tackled and several options discussed. The focus is on the Accelerator Driven System option, a hybrid technique combining a particle accelerator with a subcritical core. The scope includes technical considerations from the proton accelerator and up to the reactor core.
Discussion facilitator: Irina Petrushina (SBU/BNL).
Abstract: Coherent electron Cooling (CeC) is a proposed advanced beam cooling method that has the potential of reducing the ion beam emittance in significantly shorter amount of time compared to existing cooling methods. The newly constructed linear electron accelerator (Linac) for the CeC experiment needs to generate electron beam with the required properties in order to maximize the CeC cooling capacity. In this thesis, the author studied the beam dynamics of the CeC linac and simulated the electron beam using beam dynamics tracking code. By utilizing optimization algorithms and beam manipulation techniques, the author has explored the performance of the current CeC Linac. The author ran an end-to-end simulation to model the entire beam line from the generation of electron beam from photocathode to the transport of electron beam to the CeC Free Electron Laser (FEL) section. The results have shown many aspects of the current CeC Linac and would be beneficial to future operation, research and development.
Discussion facilitator: Jun Ma (SBU/BNL).
  • February 23, 2016: informative meeting.


Season coordinator: Dr. Silvia Verdú-Andrés.

Season 2014


Season coordinators: Prof. Sergey Belomestnykh and Dr. Qiong Wu.

Other seminars or academic events of interest

  • BNL monthly calendar
  • September 8, 2016: Particle Accelerators and Accelerator Control Systems: An Engineering Introduction by Kevin Brown. Venue: Thursday, September 8, 2016 at 4:00pm in Light Engineering Building, Room 250 at Stony Brook University.
  • September 7-8, 2016: Diversity & Inclusion workshop. Venue: September 7-8, 2016 at BNL.
  • March 10, 2016: OSTI dedicated meeting to students and postdocs to present their tools and services. Venue: Thursday, March 10, 2016 in Bldg. 467 - Room 157 (seminar room in Biology building) at BNL.
  • February 23, 2016: Proposal & Grant Writing Presentation for Students and Postdocs organized by BNL. Venue: Tuesday, February 23, 2016 in RSB 1 & 2 in Bldg. 400 at BNL.

Literature

Collection of papers and talks on Accelerator Physics & Technology and beyond:

Accelerator Facilities
Beam Cooling
M. Blaskiewicz, Cooling of High-Energy Hadron Beams, Annu. Rev. Nucl. Part. Sci. 64, 299–317 (2014).
RF Cavities
Superconductivity
H. S. Padamsee, Superconducting Radio-Frequency Cavities, Annu. Rev. Nucl. Part. Sci. 64, 175–96 (2014).
Other fields
R. M. May, Simple Mathematical Models with Very Complicated Dynamics, Nature 261, 459-467 (1976).
R. R. Wilson, Radiological Use of Fast Protons, Radiology 47, 487-491 (1946).

N.B. Some links may only work inside the BNL network.

Contact person

Please send your questions and suggestions to Silvia Verdú-Andrés