Tag Archives: Cern

Anti-Proton Decelerator quick tour


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:


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


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


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


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


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


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


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:


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:


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:


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


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


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:


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):


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




Raspberry Pi day at Cern

Yet another nice Raspberry Pi day at Cern ! Thanks to the organizer I could present the Pilogger system, and here are the slides 😉

A nice opportunity the meet the great author of http://www.framboise314.fr !


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