IOTA electron lens


The electron lens for the Integrable Optics Test Accelerator (IOTA) at the Fermilab Accelerator Science and Technology facility (FAST) has several purposes:

  • to act as nonlinear element for integrable optics
    - axially symmetric lens in solenoid
    - McMillan lens
  • to provide electron cooling for protons
    - to improve lifetime and enable experiments on space-charge dynamics
    - to study the interplay between cooling and nonlinear integrable optics
  • to enable experiments on space-charge compensation in rings with trapped electron columns

The design of the device is ongoing and it is scheduled to be completed in 2019. Construction and installation of the device is planned for 2020-2021.


  • Alexey Burov: electron cooling
  • Kermit Carlson: electrical engineering
  • Darren Crawford: operation, diagnostics
  • Nathan Eddy: instrumentation
  • Ben Freemire: electron-column simulations, diagnostics
  • Antti Kolehmainen (CERN): design and engineering
  • Valeri Lebedev: electron cooling
  • Sergei Nagaitsev: electron cooling, nonlinear integrable optics
  • Lucy Nobrega: mechanical engineering and vacuum
  • Chong Shik Park (Korea U. Sejong): electron-column simulations
  • Diego Perini (CERN): design and engineering
  • Ari Pikkarainen (Kemi U. Finland): design and engineering
  • Aleksandr Romanov: lattice design
  • Jinhao Ruan: operation
  • Vladimir Shiltsev: concept, physics, electron column
  • Giulio Stancari: design, physics, operation, team leader
  • Linda Valerio: mechanical engineering and vacuum
  • Alexander Valishev: design, physics


gs_20181119_153658_DSC_5651-Pano-2_LR.jpg (Photograph of IOTA taken by G. Stancari on Nov. 19, 2018) gs_20180727_154211_DSC_4757_LR-2.jpg (Photograph of the IOTA e-lens section taken by G. Stancari on July 27, 2018)
IOTA Electron-lens section

Layout of the electron lens in the IOTA ring: (a) schematic plan view; (b) solid drawing of
selected components:


3D model of the IOTA e-lens section in STP format: ZIP archive

2D views of the e-lens section:

Electron_Lens_Section.png F10082015-1_elens_side_view.png F10082015-2_elens_top_view.png
E-lens section [PDF] Side view [PDF] Top view [PDF]

Magnetic system

The magnetic system consists of

  • Electron-gun solenoid (existing, from TEL-2)
  • Transport solenoid
  • First toroidal section
  • Main solenoid
  • Second toroidal section
  • Second transport solenoid
  • Collector solenoid (existing, from TEL-2)
  • Orbit correctors for the circulating beam to compensate for the toroid kick

The layout of the system was optimized in this report, taking into account the dynamics of the magnetized electron beam with space charge.

Layout of the magnetic system [PDF]

Gun and collector solenoids

Gun and collector solenoids were reused from one of the Tevatron electron lenses (TEL-2).

Electrical and water flow measurements in Fermilab Technical Division, 9 Nov 2016:

20161114_142607_1_e.jpg 20161114_142756_1_e.jpg


  • Cathode and collector toroids
  • Two stripline beam position monitors (BPMs) in the overlap region
  • Split electrodes for confinement and ion removal in the overlap region
electrode_layout.png F10092939_electrodes.png
  • YAG screen and pinhole for profile measurements after the second toroidal section


  • Recombination monitor based on downstream detection of neutral hydrogen (for protons only, in electron-cooling mode) for cooling optimization and proton profiles
  • Microwave antenna for cyclotron motion to determine solenoid field, electron density and electron temperature (under study)




Electronic logbooks

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