Subscribe options

Select your newsletters:

Please enter your email address:

@

Your email address will only be used for the purpose of sending you the ITER Organization publication(s) that you have requested. ITER Organization will not transfer your email address or other personal data to any other party or use it for commercial purposes.

If you change your mind, you can easily unsubscribe by clicking the unsubscribe option at the bottom of an email you've received from ITER Organization.

For more information, see our Privacy policy.

News & Media

Latest ITER Newsline

  • Central solenoid assembly | First sequences underway

    What does it take to assemble the magnet at the heart of ITER? Heavy lifting, unerring accuracy, and a human touch. The central solenoid will be assembled from [...]

    Read more

  • Assembly | The eyes of ITER

    Supervisors ensure compliance and completion as machine and plant assembly forges ahead. In Greek mythology, Argus was considered an ideal guardian because his [...]

    Read more

  • Component repairs | Removing, displacing and disassembling

    A good repair job starts with a cleared workbench, the right tools on hand and a strong vise. This axiom, true for odd jobs in a home workshop, is also true for [...]

    Read more

  • Assembly | Set of handling tools for in-vessel installation finalized

    Inside of a test facility that reproduces the volume and geometry of the ITER vacuum vessel environment, a team from CNIM Systèmes Industriels has dem [...]

    Read more

  • 360° image of the week | The assembly theatre

    Ever since it was invented almost two centuries ago, photography has tried to capture what the human eye actually sees. Despite huge progress achieved, it has n [...]

    Read more

Of Interest

See archived entries

Neutral beam diagnostics

Right in the line of the beam

A high-precision diagnostic is about to enter into service at the ITER Neutral Beam Test Facility, where scientists are testing key aspects of ITER's external heating powerhouse—neutral beam injection.

Sixteen carbon fibre composite tiles are being mounted on the STRIKE structure. These tiles will face the brunt of the SPIDER negative ion beam ... for short periods of time ... to characterize beam uniformity and divergence. (Click to view larger version...)
Sixteen carbon fibre composite tiles are being mounted on the STRIKE structure. These tiles will face the brunt of the SPIDER negative ion beam ... for short periods of time ... to characterize beam uniformity and divergence.
Last-phase assembly activities are underway on the STRIKE calorimeter at the ITER Neutral Beam Test Facility, as carbon tiles are installed on the supporting structure. STRIKE will be used on the first of the facility's test beds SPIDER, an ITER-scale negative ion source inaugurated last June.

STRIKE is the most remarkable diagnostic planned for the SPIDER beam—the only one able to measure beam uniformity and divergence at the same time. The principle is quite simple: the calorimeter will present a perpendicular surface made of carbon fibre composite (CFC) tiles to the beam. The power deposited by the beam on the front side of the tiles will be propagated in form of heat to the rear side, where a set of infrared cameras will detect and analyze the thermal pattern in order to reconstruct beam properties.

A CAD representation of the rear side of the STRIKE calorimeter, installed inside the SPIDER vessel perpendicular to the beam. In orange, the view cones of infrared cameras. (Click to view larger version...)
A CAD representation of the rear side of the STRIKE calorimeter, installed inside the SPIDER vessel perpendicular to the beam. In orange, the view cones of infrared cameras.
In order to preserve the pattern all the way through the calorimeter, it is fundamental to minimize the heat conduction along the directions perpendicular to the beam axis, while maintaining parallel conduction. For this reason, the tiles are made of carbon fibres that are packed and oriented in the direction parallel to the beam. Fabrication requires several months and is only possible in few locations around the world.

To fully intercept the SPIDER beam—which occupies approximately one square metre—16 carbon fibre composite tiles are needed. The tiles are kept in place by a metallic structure whose position can be remotely controlled in order to diagnose the beam at different distances from the source. The structure is also equipped with electrostatic sensors and thermocouples to provide additional information.

Even if the tiles are capable of sustaining temperatures in excess of 1,000 ˚C, they cannot withstand the full power (up to 6 MW) of the SPIDER beam for long periods; hence, for long pulses, the metallic structure of STRIKE opens to allow the beam to pass through and be intercepted further along by an alternative calorimeter, the actively cooled "beam dump."

Thanks to this high-tech instrument, scientists will be able to perform precision analysis on the SPIDER beam.


return to the latest published articles