U.S. flag
        An official website of the United States government
          Here’s how you know
        Here’s how you know**Official websites use .gov**
              
              A **.gov** website belongs to an official government organization in the United States.
        **Secure .gov websites use HTTPS**
              
              A **lock** (  A locked padlock
) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. https://www.nist.gov/pml/quantum-measurement/atomic-spectroscopy/electron-beam-ion-trap-ebit/ebit-introduction
  Search NIST
    Search
              Menu

      


Close
    Topics
        All Topics
                                                        Advanced communications
                                                        Artificial intelligence
                                                        Bioscience
                                                        Buildings and construction
                                                        Chemistry
                                                        Climate
                                                        Cybersecurity
                                                        Electronics
                                                        EnergyEnvironment
                                                        Fire
                                                        Forensic science
                                                        Health
                                                        Information technology
                                                        Infrastructure
                                                        Manufacturing
                                                        Materials
                                                        Mathematics and statisticsMetrology
                                                        Nanotechnology
                                                        Neutron research
                                                        Performance excellence
                                                        Physics
                                                        Public safety
                                                        Resilience
                                                        Standards
                                                        Transportation
            Publications
            Labs & Major Programs
        Laboratories
                                Communications Technology Laboratory
                                  Engineering Laboratory
                                  Information Technology Laboratory
                                  Material Measurement Laboratory
                                  Physical Measurement LaboratoryUser Facilities
                                NIST Center for Neutron Research
                                  CNST NanoFab
                                                        Research Test Beds
                                                        Research Projects
                                                        Tools & InstrumentsMajor Programs
                                Baldrige Performance Excellence Program
                                  CHIPS for America Initiative
                                  Manufacturing Extension Partnership (MEP)
                                  Office of Advanced Manufacturing
                                  Special Programs Office
                                  Technology Partnerships Office
            Services & Resources
        Standards and Measurements
                                Calibration Services
                                  Laboratory Accreditation (NVLAP)
                                  Quality System
                                  Standard Reference Materials (SRMs)
                                  Standards.gov
                                  Time Services
                                  Office of Weights and MeasuresSoftware
                                                        Data
                                Chemistry WebBook
                                  National Vulnerability Database
                                  Physical Reference Data
                                  Standard Reference Data (SRD)
                                                        Storefront
                                                        License & PatentsComputer Security Resource Center (CSRC)
                                                        NIST Research Library
            News & Events
        News
                                                        Events
                                                        Blogs
                                                        Feature Stories
                                                        AwardsVideo Gallery
                                                        Image Gallery
                                                        Media Contacts
            About NIST
        About Us
                                Leadership
                                  Organization Structure
                                  Budget & Planning
                                                        Contact Us
                                                        Visit
                                                        Careers
                                Student programsWork with NIST
                                                        History
                                NIST Digital Archives
                                  NIST Museum
                                  NIST and the Nobel
                                                        Educational Resources
 
 Physical Measurement Laboratory /                  Quantum Measurement Division
      Atomic Spectroscopy Group
    
      
  Electron Beam Ion Trap (EBIT)
                            Expand or Collapse
          EBIT Introduction
                      EBIT Operating Principles
                      EBIT History
                                              Expand or Collapse
                EBIT Milestones
                                  The History of NRL's Involvement in NIST's EBIT Facility
                      Other EBITs Around the Globe
                      Typical Operating Parameters of the NIST EBIT
                      EBIT Design Tutorial
                      Guide to Reported NIST EBIT Data
                      Current and Future EBIT Research
                      X-ray Polarization
                      Visible and UV Spectroscopy
                      Electron-Ion Collisions
                                              Expand or Collapse
                Radiative and Dielectronic Recombination
                      Trapped Ion Dynamics
                                              Expand or Collapse
                Charge state simulation
                      Atomic Lifetimes
                      Ion-Surface Interactions
                      EBIT Bibliography
                      People Using the EBIT Facility
                                              Expand or Collapse
                2004 EBIT Hike
                                  EBIT Group Photo Montage
                                  EBIT Second Group Photo Montage
                      Fellowships for Research at the NIST EBITEBIT Introduction

Share
  Facebook
                      Linkedin
                      Twitter
                      Email

IntroductionWhat is an EBIT?EBIT
  The electron beam ion trap (EBIT) is a small-scale laboratory instrument which uses a tightly focused and energy-tunable electron beam to create, trap, and probe highly charged ions. Virtually any charge state of any element in the periodic table can be studied using an EBIT simply by injecting the desired element and adjusting the electron beam energy appropriately. Here at NIST, we have produced and recorded x-ray spectra from charge states as high as Bi73+, which corresponds to the neon-like state (only ten electrons remain). We have run our EBIT at electron beam energies up to 33 kV which is theoretically enough to produce charge states as high as U90+. At Lawrence Livermore National Laboratory (LLNL), researchers recently used a high energy version of the EBIT called Super-EBIT to create fully-stripped uranium (92+).One of the primary ways of studying the ions in an EBIT is spectroscopy, which involves observing and analyzing the radiation (usually x-ray) emitted by the ions after collisional excitation by the electrons from the beam. The radiation is viewed through side windows at 90 degrees to the electron beam direction. Typically, a wide range of low and high resolution spectrometers are employed, including Bragg crystal x-ray spectrometers and solid state silicon and germanium detectors.Operating PrinciplesThe primary component of the EBIT is the electron beam, which is formed in a commercial Pierce-type gun and is guided, accelerated and focused by several magnetic coils and high voltage electrodes. The electron beam is decelerated and finally extinguished at a cooled copper electrode called the collector. The maximum electron beam energy is determined by the positive voltage bias applied to the drift tubes (basically a set of three cylindrical copper tubes) and can range from about 700 eV to over 30,000 eV in the NIST EBIT. In the super-EBIT at Lawrence Livermore National Laboratory, the electron beam energy can extend beyond 200,000 eV. The maximum achievable electron beam current depends on the drift tube voltage, but usually is around 150 mA. The electron beam starts off with a diameter of approximately 1 millimeter and is then compressed to less than 100 micrometers by a 3 tesla axial magnetic field provided by a superconducting Helmholtz-pair magnet.The electron beam performs three functions: it creates the highly charged ions by removing electrons via electron impact ionization; it confines the ions by providing a trapping potential in the radial direction (the space charge of the electron beam is negative, which attracts the positively charged ions); and it excites radiative transitions in the ions, so that they can be studied spectroscopically.HistoryHistorically the design of the first EBIT prototype is connected to the name of Morton Levine and Ross Marrs. Their goal was to develop an instrument based on the principles of an earlier device called an "EBIS" (electron beam ion source) but with some fundamental improvements, allowing higher charge sates to be formed, and allowing in situ spectroscopic access to the ions. In contrast to the case for EBIS, X-ray spectroscopy was to be the primary method of studying ions produced by EBIT.EBIT was not designed to be an ion source like its ancestor the EBIS. Since the launch of the first EBIT, however, its operation for production of very high charge states was so successful that there are now applications which are based on the extraction of ions from the machine.After the construction of the first EBIT at Livermore, a second advance was made -- development of a high energy version of the machine. With this instrument -- usually referred to as Super EBIT -- even the highest charge states of all the elements in the periodic table are accessible. Recently the Super EBIT demonstrated production of fully stripped uranium, which has the highest atomic number among the naturally occurring elements.The energy of the Super EBIT electron beam can be varied up to just beyond 200 keV. For most applications, however, one does not need such high electron beam energies. In fact, 40 keV is enough to theoretically strip any element to the helium-like state, and even to fully strip elements up to an atomic number of 50. Limitations on maximum obtainable current densities however make significantly higher electron beam energies desirable.Soon after the demonstration of EBITs effectiveness, decisions were made at NIST, the Naval Research Laboratory (NRL), and Oxford University (United Kingdom) to build similar machines. The primary motivation was the possibility of doing high precision spectroscopy of highly charged ions. Due to their close proximity and long-standing previous collaboration on other spectroscopic work, NRL and NIST decided to team up to build a single EBIT for joint use in the metropolitan Washington DC area. Vacuum and internal components for both the new U.S. and U.K. machines were made in the Oxford machine shops as part of a collaboration between the institutions in the two countries. (More detail on the history of NRL's involvement.)The assembly of the new EBITs progressed in parallel, reaching the final phase in August of 1993 when the NIST EBIT became operational. There are already new designs and projects underway, proving the wide acceptance of the possibilities offered by the EBIT to the scientific community.A brief listing of some milestones in the development of the NIST EBIT facility.
  Physics, Atomic / molecular / quantum and Spectroscopy

    
    Created October 6, 2009, Updated August 25, 2016 ‹ Electron Beam Ion Trap (EBIT)
              EBIT Operating Principles ›
 HEADQUARTERS
            100 Bureau Drive
              Gaithersburg, MD 20899301-975-2000
            Webmaster | Contact Us | Our Other Offices
        Twitter
            
Facebook
            
LinkedIn
            
Instagram
            
YouTube
            
Giphy
            
RSS Feed
            
Mailing List
                              How are we doing? Feedback

  
  Site Privacy
                      Accessibility
                      Privacy Program
                      Copyrights
                      Vulnerability Disclosure
                      No Fear Act Policy
                      FOIA
                      Environmental Policy
                      Scientific Integrity
                      Information Quality Standards
                      Commerce.gov
                      Science.gov
                      USA.gov
                      Vote.gov