EEVblog Electronics Community Forum

EEVblog => EEVblog Specific => Topic started by: EEVblog on January 01, 2016, 07:56:57 am

Title: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: EEVblog on January 01, 2016, 07:56:57 am
A 1 hour tour of the Australian Synchrotron.
From breadboards to 35MW Kystron RF power amplifiers!

https://www.youtube.com/watch?v=27KRtJ-2sVY (https://www.youtube.com/watch?v=27KRtJ-2sVY)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: ataradov on January 01, 2016, 08:37:04 am
Just out of curiosity, if video was made in 2013, why it is released only today?

Awesome stuff, BTW.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: EEVblog on January 01, 2016, 08:41:22 am
Just out of curiosity, if video was made in 2013, why it is released only today?

Because I'm a lazy arse.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: ataradov on January 01, 2016, 08:42:39 am
Because I'm a lazy arse.
That's fair. I though there may be something more to this, like waiting for clearances, approvals and things like that.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: SL4P on January 01, 2016, 08:48:53 am
FWIW, about 100m over the back fence of the synchrotron is Telstra's GOC (Global Operations Centre) - lots of people shuffling data around the country and world... on a big display wall!

http://www.itnews.com.au/gallery/inside-the-telstra-global-operations-centre-154094 (http://www.itnews.com.au/gallery/inside-the-telstra-global-operations-centre-154094)

I haven't been inside for several years, but I've been to other offices onsite,  - so I guess a lot of the tech is still in place.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: pickle9000 on January 01, 2016, 09:43:14 am
That was a good one, totally enjoyed the tour.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Red Squirrel on January 01, 2016, 10:20:56 am
That was pretty cool, for some reason it kinda reminds me of the death star. All this talk about beams and focusing energy. So many brains involved in designing and building something like this though, it's quite impressive.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: HP-ILnerd on January 01, 2016, 11:44:58 am
Awesome Video!

Are they sellin' those shirts anywhere?
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: HighVoltage on January 01, 2016, 12:54:41 pm
What a great Video.
Thank you.

I have been to the Hamburg DESY a few times and much was looking very familiar in your video.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: ornea on January 01, 2016, 01:04:07 pm
 :-+ :-+ :-+ :popcorn:
Thoroughly enjoyed the video. Thanks.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: WN1X on January 01, 2016, 01:10:52 pm
Yes, a very enjoyable video  :-+

I only have one question....where were they hiding the flux capacitor?  :-//
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: CrashO on January 01, 2016, 01:37:28 pm
Are they sellin' those shirts anywhere?
I did a search for it and found a bunch of blogs referring to it being sold by Snorg Tees (http://www.snorgtees.com/) (in 2010..). But they don't seem to sell it anymore  :-\
Highest resolution I can find from the image is this one, not much resolution wise, but for the people who want to print one onto their shirts it'll work I guess  ^-^

(http://teecraze.com/images/snorg/nuclearphysics.jpg)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: German_EE on January 01, 2016, 02:07:40 pm
 :-+  :-+  :-+  :-+

Good video, lots of heavy engineering content although it's a shame that the machine was running whilst you were there because I would have liked to have seen the beam source and accelerator.

35 MW Amplifiers, be still my beating heart  :)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Brumby on January 01, 2016, 02:10:08 pm
35 MW Amplifiers, be still my beating heart  :)

Peak ... and at a very low duty cycle.



But, yeah ... impressive.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Alex Eisenhut on January 01, 2016, 03:19:49 pm
This is the proper way of things; a vacuum tube surrounded by lowly transistors...  :)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Steffen on January 01, 2016, 03:22:35 pm
For me this video was very nice. I'm working at DESY Hamburg (http://www.desy.de/index_eng.html) and know quite much about accellerators. We also run few accellerators like PETRA (http://petra3.desy.de/index_eng.html) and DESY (http://desy2.desy.de/) as ring accellerators and FLASH (http://flash.desy.de/) and later on the European XFEL (http://www.xfel.eu/).
Interesting to see was, that some stuff that was standing around there was common to me. Like the klystron cathode voltage supplies for the 35MW pulsed Klystrons. (Blue PPT Racks). If those could be bouncer modulators? The cyclotron poster at 3:45 is also hanging around in my lab. According to the size of waveguides laying around in the shelfs it could be possible that there might be some 750ish MHz RF system there.
Interesting also was, that the Australian Synchrotron also operates in the top up mode like we do at PETRA. Our efficiency is also above 98%. Maybe there is also some competion of different institutes? :)
I'm working for the high power RF group for linear accellerators and have quite a lot to work with klystrons, pulse transformers, modulators, electronics, wavegudies and all sort of stuff that belongs to one typical RF assembly for particle accellerators. In this respect I would liked to have seen more details bout the high power RF stuff in the Australian Synchrotron.
Dave: If you ever have the chance to travel to Hamburg, Germany I wold be proud to show you our facilities and construction progress on our newest baby XFEL.
All others are invited too to visit our facility. Details for visitors (http://www.desy.de/about_desy/visiting_desy/hamburg/index_eng.html)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 01, 2016, 03:43:23 pm
WOW!  I haven't watched all the previous 835 videos, but that was the best one yet!  I have to admit I was getting bored with yet another test equipment teardown. But this was GREAT!  To use an American baseball term, you "hit it out of the park".  Dunno if there is an equivalent in cricket (or whatever you Empire guys play?)?

Anybody here work at CERN?  I'll fly in to operate camera/sound for Dave if somebody can get him into the LHC!
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: G7PSK on January 01, 2016, 10:27:15 pm
Another great but,When do we get the tear down video. :-DD
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: SeanB on January 01, 2016, 10:30:40 pm
WOW!  I haven't watched all the previous 835 videos, but that was the best one yet!  I have to admit I was getting bored with yet another test equipment teardown. But this was GREAT!  To use an American baseball term, you "hit it out of the park".  Dunno if there is an equivalent in cricket (or whatever you Empire guys play?)?

Anybody here work at CERN?  I'll fly in to operate camera/sound for Dave if somebody can get him into the LHC!

Dexterslab did a tour of the LHC a while ago, might be worth a look at his video.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Ketturi on January 02, 2016, 01:16:04 am
Dave, I see you have done your homework ;).
Thanks for really interesting and informational video. I'm still bit bitter that I missed opportunity to visit CERN when our physics class went to tour there (not including me due some financial issues I had).
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: AF6LJ on January 02, 2016, 01:54:07 am
Good video Thanks Dave.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Brumby on January 02, 2016, 05:15:43 am
To use an American baseball term, you "hit it out of the park".  Dunno if there is an equivalent in cricket (or whatever you Empire guys play?)

The basic cricket term is "Hit for 6" - when the ball is hit over the boundary on the full.  You can add "into the carpark" when a really big hit puts it over the stands (extremely rare) - which is the direct equivalent of "hit it out of the park".
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: EPLan on January 02, 2016, 01:17:25 pm
I'm only casually familiar with the "Diamond Light Source (https://en.wikipedia.org/wiki/Diamond_Light_Source)" in the UK so it was quite interesting to see a more in-depth tour of a synchrotron. The Wikipedia entry suggests this facility has had some ups and downs politically, even this recent article(7/12) (http://www.ibtimes.com.au/federal-government-saves-australian-research-facility-520-million-investment-1490127) mentions Turnbull "saving" the facility with a $520 million investment.

Found it a bit strange reading the odd YouTube comment stating that the video was boring, I just assumed anybody interested in electronics would be interested in science generally.  :-\
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Brumby on January 02, 2016, 02:06:00 pm
Found it a bit strange reading the odd YouTube comment stating that the video was boring

Perhaps they were expecting to see beams blowing up stuff or pretty colourised images of an experiment in progress - but with white floors, racks of gear and conversation, they had to listen and think to appreciate the place.  Too much hard work for some, I expect.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 02, 2016, 04:35:38 pm
Dexterslab did a tour of the LHC a while ago, might be worth a look at his video.

The only reference to "Dexter's Lab" I can find is some goofy cartoon.
I presume you are referring to something serious?
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: gadget73 on January 02, 2016, 06:07:05 pm
Particle accelerators are neat stuff.  The company I work for runs a couple.  One facility has an old Lineac in service that is used largely to color gemstones and do some sort of processing on silicon wafers.  They also have a thing called a Rhototron, which is like a much smaller version of a Cyclotron.  It has a couple of beam paths, one is strictly electron beam, two of the others aim at a tantalum target to produce X-ray.  Its used for commercial irradiation of things.  The cavity of the unit is a circular enclosure, probably about 5 feet across,  surrounded by magnets to bend and accelerate the beam to the proper levels.  It uses some large vacuum tube as the RF source as well. 
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: jancumps on January 02, 2016, 06:14:11 pm
Dexterslab did a tour of the LHC a while ago, might be worth a look at his video.

The only reference to "Dexter's Lab" I can find is some goofy cartoon.
I presume you are referring to something serious?
dexterslab is one of our fellow forum members.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: SeanB on January 02, 2016, 06:45:00 pm
Dexterslab did a tour of the LHC a while ago, might be worth a look at his video.

The only reference to "Dexter's Lab" I can find is some goofy cartoon.
I presume you are referring to something serious?
dexterslab is one of our fellow forum members.
https://www.eevblog.com/forum/profile/?u=83 (https://www.eevblog.com/forum/profile/?u=83)

http://dexterslab2013.blogspot.co.uk/ (http://dexterslab2013.blogspot.co.uk/)

https://www.youtube.com/watch?v=Mrr5XV7sfMs (https://www.youtube.com/watch?v=Mrr5XV7sfMs)

https://www.youtube.com/watch?v=jbildyILX8g (https://www.youtube.com/watch?v=jbildyILX8g)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: JoeLaBidouille on January 02, 2016, 10:50:22 pm
Pretty cool video Dave.

Not so far from the CERN, there is also a synchrotron in Grenoble (French alps). It works on same principles and this big scientific tool is shared between multiple E-U countries
The ring is longer with 844 meters of circumference compared to 214 meters for the Australian one.
https://en.wikipedia.org/wiki/European_Synchrotron_Radiation_Facility (https://en.wikipedia.org/wiki/European_Synchrotron_Radiation_Facility)

I attach some picture from my last visit (all visit are free and guided, this is a real enjoyment)


This synchrotron is only few hundreds of meter from an other toy called ILL Neutrons for science. This is a beam source of neutron, the most intense in the world.
Thunderf00t used to work there:
https://www.youtube.com/watch?v=IaQI21LwueM (https://www.youtube.com/watch?v=IaQI21LwueM)


Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 02, 2016, 11:51:56 pm
I am assuming that big light-tone metal cast bracket is aluminum (for its non-magnetic properties).
But just at the end of that bracket there appears to be an ordinary steel-strap, the kind used for packing and shipping.
How do they keep that conductive (and ferrous/magnetic) loop from becoming a secondary transformer winding?

(https://www.eevblog.com/forum/blog/eevblog-836-tour-of-the-australian-synchrotron/?action=dlattach;attach=191126;image)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Yansi on January 03, 2016, 01:23:52 am
Kystron... whats that? I know only klystron. Misstype or is it anything else? https://en.wikipedia.org/wiki/Klystron

The proffesor was very good at responding to Dave's biting questions. A smart man he is!

Nice and interesting video, thank you.

And is also interesting those two guys really look they know every cable and machine in their facility. Very nice!
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: gadget73 on January 03, 2016, 02:04:22 am
I am assuming that big light-tone metal cast bracket is aluminum (for its non-magnetic properties).
But just at the end of that bracket there appears to be an ordinary steel-strap, the kind used for packing and shipping.
How do they keep that conductive (and ferrous/magnetic) loop from becoming a secondary transformer winding?

(https://www.eevblog.com/forum/blog/eevblog-836-tour-of-the-australian-synchrotron/?action=dlattach;attach=191126;image)

Likely a non-magnetic stainless steel alloy if I had to guess.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Red Squirrel on January 03, 2016, 02:08:58 am
I was thinking, could that "storage ring" concept actually be used to store significant amounts of energy, like say for power generation?  You have a solar power plant or other plant that runs during the day, then extra power is stored to be used throughout the night.   Or is this really only limited to small particle energy?  Of course you would need a way to convert it back to electricity as well.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Zad on January 03, 2016, 02:09:19 am
I only have one question....where were they hiding the flux capacitor?  :-//

The storage ring is one huge flux capacitor!

Lets see ya get that rig up to 88 mph!
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 03, 2016, 02:17:27 am
I was thinking, could that "storage ring" concept actually be used to store significant amounts of energy, like say for power generation?  You have a solar power plant or other plant that runs during the day, then extra power is stored to be used throughout the night.   Or is this really only limited to small particle energy?  Of course you would need a way to convert it back to electricity as well.
Even if you had a 100% efficient way of converting the energy back into commercial-grade power, the whole thing seems horribly inefficient as a "storage" device.
IIRC they said the beam was 1MeV (?) @ 200mA = 200KW  But then they said it took 4MW of power. Even if only half of that power were used directly for the storage loop, the cost/benefit ratio is hugely negative.  Which is why we are still using electro-chemical gadgets like batteries, and electro-mechanical gadgets like flywheels, etc.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: g.lewarne on January 03, 2016, 02:35:27 am
I was thinking, could that "storage ring" concept actually be used to store significant amounts of energy, like say for power generation?  You have a solar power plant or other plant that runs during the day, then extra power is stored to be used throughout the night.   Or is this really only limited to small particle energy?  Of course you would need a way to convert it back to electricity as well.
Even if you had a 100% efficient way of converting the energy back into commercial-grade power, the whole thing seems horribly inefficient as a "storage" device.
IIRC they said the beam was 1MeV (?) @ 200mA = 200KW  But then they said it took 4MW of power. Even if only half of that power were used directly for the storage loop, the cost/benefit ratio is hugely negative.  Which is why we are still using electro-chemical gadgets like batteries, and electro-mechanical gadgets like flywheels, etc.

Use my new, upcoming "Beamerizer" and make it 800% more efficient!



But in all seriousness, that was a cool video dave, thankyou :)
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Red Squirrel on January 03, 2016, 02:53:21 am
I was thinking, could that "storage ring" concept actually be used to store significant amounts of energy, like say for power generation?  You have a solar power plant or other plant that runs during the day, then extra power is stored to be used throughout the night.   Or is this really only limited to small particle energy?  Of course you would need a way to convert it back to electricity as well.
Even if you had a 100% efficient way of converting the energy back into commercial-grade power, the whole thing seems horribly inefficient as a "storage" device.
IIRC they said the beam was 1MeV (?) @ 200mA = 200KW  But then they said it took 4MW of power. Even if only half of that power were used directly for the storage loop, the cost/benefit ratio is hugely negative.  Which is why we are still using electro-chemical gadgets like batteries, and electro-mechanical gadgets like flywheels, etc.

Yeah was thinking that too, I guess there is probably not a more efficient way to put the energy in... we'll have to wait till the batterizer comes out I guess and daisy chain a bunch together.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: ECEdesign on January 03, 2016, 03:51:01 am
Am I the only one that noticed the copper strips around the walls?  I assume that is their ground bus  :-//
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Steffen on January 03, 2016, 10:15:19 am
Exactly, the copper strips are there for grounding the concrete blocks as well as devices connected to it.  But it is more for potential equalisation. Usually the real grounding (according to VDE) goes to special joints in the building structures which connects to the metal mesh in the concrete structures.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: German_EE on January 03, 2016, 11:20:39 am
Grounding seems to be something that the Germans are very good at. Yesterday I was standing in front of TK Max waiting for SWMBO and I noticed that someone had fixed a ground strap to the metal window frame of the shop. The chances of that frame getting energized are tiny but someone grounded it anyway.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 03, 2016, 06:40:44 pm
How do they detect the electron "bunches" going around the loop? I presume they need to know where they are so that they can synchronize the operation of the gadgets that keep the energy "topped off".  And to synchronize the "pump" electromagnets, etc.  But how do they do that without putting something into the path and presumably attenuating the energy?
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: SeanB on January 03, 2016, 07:56:53 pm
Very easy to detect high energy electrons, especially as you are bending them in a magnetic field. Simplest is a silicon photodiode to detect the rather large radiation pulse, or simply use a probe to detect the RF radiation as it passes by. Then you use some digital delays so the next time they come past ( you know how long it takes to go around) the acceleration energy is just in the right phase to pump up the energy. If your pulses are all a known length and timing you skew the pump pulses so that every x number of revolutions through the same pulse will get pumped, but in the interim your pumping will have done them all.

As well remember that the experiment tapping points are in line with the beam bending magnets, the beam itself does not lose much energy in a straight line, only when it turns a bend in a magnetic field. Thus there is a single pulse the length of the beam as it passes, and as it is a magnetic field I would also guess it is polarised somewhat and not a random polarised beam, but somewhat coherent phase wise with a very sharp rise and fall time.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: jahonen on January 03, 2016, 08:07:39 pm
How do they detect the electron "bunches" going around the loop? I presume they need to know where they are so that they can synchronize the operation of the gadgets that keep the energy "topped off".  And to synchronize the "pump" electromagnets, etc.  But how do they do that without putting something into the path and presumably attenuating the energy?

Probably by same manner than in LHC, using a beam current transformer, which is a toroidal transformer arranged so that the beam travels through the center of the toroid. Then, the secondary current gives number of bunches, and if the transformer is fast enough, then it can sense the current contribution of each individual bunch.

For any storage ring or synchrotron needs very precise RF system to hold the bunches in so called RF-buckets (there is a phase loop which measures the beam and adjusts the RF), and that also means that RF frequency is set to such value that the RF wavelength is a exact multiple of the ring circumference length. That system give all the timings for all those who need it.

There is a description of BCT systems in LHC design report: https://edms.cern.ch/ui/file/445861/6/Vol_1_Chapter_13.pdf

BTW, those dipole magnets have pretty much constant field strength, so having shorted turns is probably not an issue, since magnet current is essentially DC.

Regards,
Janne
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: daqq on January 04, 2016, 07:31:26 am
Nice video Dave, thanks!

Now... where's the teardown?
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: SeanB on January 04, 2016, 07:37:55 am
Nice video Dave, thanks!

Now... where's the teardown?

I think they confiscated his screwdriver at the entrance...............
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: electrophiliate on January 04, 2016, 12:50:55 pm
Interesting hardware! Regarding efficiency, that is difficult to guess. I assume the 200mA is referring to the total current in the storage ring. I had a quick look again and don't feel like watching the whole video again, but my impression was that the initial 90kV (electron gun) is boosted to 100MeV using RF amplifiers (peak power 35MW, 10uS pulses, low duty cycle), then the booster ring increases that to 3GeV. The display was showing an injection top up current on the order of a few uA at most. The total average power for the whole facility was 4MW.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Richard Crowley on January 04, 2016, 02:02:49 pm
Doh!  I forgot that simply bending/turning the beam "accelerates" it. So, right at the bend you can detect the bunches quite simply without interfering with the main beam.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: TinkerFan on January 06, 2016, 02:17:31 pm
I really enjoyed that video. This stuff is really fascinating, especially the variety of things they use it for. I actually did my work experience last year at the company that built (parts) of that Synchroton (FMB Berlin) and I looked every morning at a piece of a beamline from the Australian Synchroton. And guess what, the vacuum pumps they use while the thing is operating are produced by - Agilent!
http://www.agilent.com/en-us/products/vacuum-technologies/high-vacuum-pumps#1 (http://www.agilent.com/en-us/products/vacuum-technologies/high-vacuum-pumps#1)
I think they appeared somewhere in the video, but I cannot find them anympore.

But what I didn't understand, is how they produce the diffrent wavelengths. Do they insert the 'light' at diffrent wavelengths or do they 'divide' the wave in the beamlines?

Now after 2 years of silent watching I finally arrived in this Forum... ;D
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: dexters_lab on January 07, 2016, 11:14:46 pm
Dexterslab did a tour of the LHC a while ago, might be worth a look at his video.

The only reference to "Dexter's Lab" I can find is some goofy cartoon.
I presume you are referring to something serious?
dexterslab is one of our fellow forum members.
https://www.eevblog.com/forum/profile/?u=83 (https://www.eevblog.com/forum/profile/?u=83)

http://dexterslab2013.blogspot.co.uk/ (http://dexterslab2013.blogspot.co.uk/)

https://www.youtube.com/watch?v=Mrr5XV7sfMs (https://www.youtube.com/watch?v=Mrr5XV7sfMs)

https://www.youtube.com/watch?v=jbildyILX8g (https://www.youtube.com/watch?v=jbildyILX8g)

did someone mention me?  ^-^

the cern openday was awesome, there is supposed to be another long shutdown in the next year or so... hopefully they will run another openday program when it happens, Dave should make an effort :-)

been putting off watching this vid as it's an hour long so needed to find the right time to watch it!
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: lpickup on January 14, 2016, 02:30:18 pm
Wow, that was a great video!  Thanks Dave.

This is not my field, and it's been quite awhile since college physics, so I may have some really basic questions, but I would really appreciate learning more about this.

1)  What is the ultimate purpose of using this giant machine to generate essentially IR, visible light, UV and X-rays, as opposed to say using an X-ray machine at the dentist's?  Is it essentially the fact that you can get a much more energetic ("brighter") output?  And that higher energy is necessary to perform the type of experiments that are being done there?

2)  So I followed what they were saying that the beam attenuates (loses energy) due to non perfect vacuum, and more importantly due to the bending acceleration of the beam.  So would that mean that a larger ring, with more subtle bends, would attenuate less?  Or does it all come out in the wash because ultimately the beam has to bend  a full 360 degrees anyway?  (and thus the non-vacuum source of the attenuation would actually be greater in the larger ring)

3) Did I understand the beam timings correctly?  The pulses are at a 2GHz frequency and each pulse is 23ps long?  So in other words, a new electron bunch comes along every 500ps and are 23ps in "length" (giving a gap of 477ps?) 

3a)  In the scope display at 49:05, my understanding is that it was displaying a single beam measurement device, and each of the large "blobs" represented the electron bunches passing by the detector.  But what is the gap?  Is there an intentional "quiet" part of the beam with no bunches?  Is this where new bunches are injected into the beam?

4) So when the main beam is tapped off for one of the experiments, I assume that one (or more) bunches of electrons are redirected off the main ring and into the experiment's beam line.  Presumably these bunches would have to be replaced by new bunches to maintain the total ring current of 200mA.  How is this managed?  Are bunches stripped from the beginning (or end) of the pulse train and then injected at the opposite?

Fascinating stuff!


Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: Z80 on January 15, 2016, 02:14:26 pm
Hi, I used to work at a large synchrotron here in the UK some years ago so can give you a bit of info although I'm no physicist.

1) Essentially yes, the luminosity, spectral purity and energy level are the reasons why they are generated this way.  X-ray crystallography for instance needs very bright hard X-rays which couldn't be made practically with a conventional tube.  The higher the energy, the shorter the wavelength, the better the resolution.

2) The energy is attenuated by bending the beam, but in the case of a synchrotron this is what you want.  As the electron beam is bent, photons are emitted (synchrotron light) and this is what is sent off down the beam lines.  In fact to increase the energy the beam is intentionally bent in devices called wigglers which are just an array of very powerful magnets which pull the beam back and forth to shake out the photons.  Increasing the size of the ring allows you to store a more powerful beam, the energy is limited by how much the magnets can bend it in one go.

3) I don't remember the timings off hand, but the electrons travel round in bunches yes.  This is due to the way they are accelerated.  Energy is pumped in by an RF field, the electrons being charged are pushed along by it and all end up collecting on the wave peaks (like surfers in the ocean).

4) It's not the electrons that are used, they just go round and round the ring.  Whenever they are deflected, physics happens and synchrotron radiation is given off.  Think of the electrons like a wet sponge being swung round on a piece of string, the water flying off is the radiation.

Regarding extracting energy from the beam mentioned earlier, yes you can.  A moving charged field can be coupled to and energy extracted, this is exactly how microwaves are generated in a magnetron.  I saw a research experiment when I last visited the lab where an RF cavity was used to extract the energy out of the end of a linear accelerator beam (the beam is usually just dumped).  This energy was fed back to the other end which significantly reduced the power required to keep the beam flowing, interesting stuff indeed.
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: tpw_rules on January 22, 2016, 07:32:08 pm
It seems they're a bit lax on radiation safety, actually. Do you know the numbers that people are actually exposed to? I visited a cyclotron used to produce nuclear medical imaging chemicals (tracers and stuff). In addition to having a 7 foot thick concrete door to the machine, I was required to wear an electronic dosimeter to record my exposure during my visit. They had Geiger counters for your feet and hands to make sure you didn't track anything out. Does the concrete do a good enough job to not need any of this? Are Australian regulations different? Certifying that you're meeting maximum exposure limits is pretty easy if you don't know what it is...
Title: Re: EEVblog #836 - Tour Of The Australian Synchrotron
Post by: michelinux on October 16, 2016, 10:05:39 pm
Elettra Synchrotron in Italy:

https://www.elettra.trieste.it/lightsources/elettra/beamlines.html (https://www.elettra.trieste.it/lightsources/elettra/beamlines.html)