Tag Archives: Cern

3D printed Synchrotron Magnet replica

 

The Cern Proton-Synchrotron (PS) is a fascinating machine. While there are many synchrotrons around the world, this one started its operation in 1959. The PS, which is nowadays part of the acceleration chain of the Large Hadron Collider (LHC), measures 628 meters of circumference. It was the first strong-focusing synchrotron (or alternating-gradient focusing), at a time when synchrotrons look like the BLN Cosmotron.

The PS main magnet units combine dipole and quadrupole magnetic functions, weight more than 30 tons and are around 4.2 meters long.

There are a 100 of these magnets along the PS ring. Some coils have been replaced, but they are still the same and the yokes are untouched.

For more details about the PS and its history, there is a complete and nicely written report available on the Cern website: http://cds.cern.ch/record/1359959

In 1959 John Adams (leader of the construction team at that time) announced the successful acceleration of protons up to 24GeV.

If you pay attention, on the picture you can spot a small scale model on the desk.

That is the target of this blog post.

2-0290.jpgThere is plenty of documentations and archives at Cern, and it was impressive to find the original mechanical drawings of the magnets. So I started Fusion360 and played with the drawings. Of course, there are yet 3D models files, but they are extremely detailed and it would shortcut the fun.

Let start with the yokes:

The magnet blocks stand:

Coils, supports and feet:

And let’s print it :

The scale is 1:20 and pictures bellow show the difference with the real thing:

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The STL files are in this repository : https://github.com/pierre-muth/PSMagnet

Thanks for reading !

Creative Commons License

Images from Cern are free of charge for educational and informational use. The Cern term of use for audiovisual media can be find here : https://copyright.web.cern.ch/ . This project was realized as a hobby, outside Cern.

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Anti-Proton Decelerator quick tour

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IMG_5399I recently wrote a project page about re-purposing a flip-dot bus display for the Anti-proton Decelerator control-room. It maybe interesting to show you with pictures how this synchrotron looks like.

The Anti-proton Decelerator (AD) is a 182 meter long synchrotron. Its aim is to lower the energy of anti-protons. In contrary of the majority of the existing synchrotrons, the AD is used as a decelerator, producing low energy anti-proton and send them to different experiments. For the details, have a look on the official web page.

The AD stands inside a concrete tunnel build inside a large hall:

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Before accessing the synchrotron ring, we can make a quick stop by the AD control-room (ACR):

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The hall with the concrete shielding is conveniently visible from the ACR:

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Down in the hall, we can find the access system for the machine tunnel:

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This special door will control your personal dosimeter and your identity with an iris scanner:

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Once in the ring tunnel, you’ll meet the AD itself. Here we are facing two of the main dipole magnets (in blue):

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And right after we can see the vacuum pipe going through quadrupole magnets (focusing elements, in red):

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On the next picture you will see on the right where the anti-protons come from. Behind the wall is the target and horn area. On the left starts the injection region where we can see the vacuum pipe literally going through the blue dipole yoke:

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In the next strait section we will meet the electron cooler, one of the rare device able to reduce the size of a charged particles beam:

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Right after, these two big silver colored blocks are radio-frequency (RF) cavities. In general RF cavities are used in synchrotron to change (increase or decrease) the particle beam energy. These two ones are used in the AD to change the shape of the beam:

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Continuing along the ring you’ll meet a lot of magnets to steer and focus the beam:

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The stochastic cooling system is another remarquable element of the AD, it is a beam size reduction system:

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Without entering into the details it consists of beam sensors and fast kicker elements (electro-static). The sensors signal is amplified and transmitted to the kicker elements that are installed at the opposite side of the ring. The transmission is faster than the particles take to make half a turn of the synchrotron.

If we exit the ring tunnel, we can pass by the stochastic cooling amplifiers:

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And the powering system for the injection element, able to deliver a controlled pulse of hundreds of kilo-volts. Most noticeably are the cable coils (Pulse Forming Network):

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I hope you enjoy this little tour, and thank you for reading.

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