Collider status reports on-line

[Martin Riddle]

On 26 Oct 2019 04:42:49 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Jeroen Belleman wrote...

Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
omnilobe@gmail.com wrote...

The Large Hadron Collider uses big diodes in color photos.
What can you tell us about the big diodes?
The LHC superconducting bending magnets are arranged in series
strings of 154 powered by a single 13kA power supply. In the
event of a quench of one of the magnets, the diodes divert the
current around it while the whole string is ramped down.

They are bespoke 75mm diameter diffusion-type diodes. They
are clamped between two heat sinks and are kept at liquid
helium temperature.

Thanks, Jeroen. Any idea what their forward voltage drop is,
during the 13kA quenching event?

The forward voltage during a quench is of the order of 6V,
dropping rapidly as the diode heats up.

Does the diode have a part number and datasheet?

I had an exchange with the guys working with these things.
They say it's similar to the Dynex DS2101SY for which they
gave me a data sheet. I can't seem to find it on Dynex's
site, but I have a copy here:
http://cern.ch/jeroen/tmp/DYNEX_DS2101SY.pdf> (97kB).

Very interesting, 113mm dia, 79kA peak capacity. I don't
suppose it needs much reverse-voltage capability?

Jeroen Belleman

<https://ocem.eu/en/project/particle-cern-lhc-quadrupole-dipole-diode-stacks-3/>

Cheers

 

[Jeroen Belleman]

On 2019-10-26 15:20, Winfield Hill wrote:

Martin Riddle wrote...

Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
omnilobe@gmail.com wrote...

The Large Hadron Collider uses big diodes in color photos.
What can you tell us about the big diodes?
The LHC superconducting bending magnets are arranged in series
strings of 154 powered by a single 13kA power supply. In the
event of a quench of one of the magnets, the diodes divert the
current around it while the whole string is ramped down.

They are bespoke 75mm diameter diffusion-type diodes. They
are clamped between two heat sinks and are kept at liquid
helium temperature.

Thanks, Jeroen. Any idea what their forward voltage drop is,
during the 13kA quenching event?

The forward voltage during a quench is of the order of 6V,
dropping rapidly as the diode heats up.

Does the diode have a part number and datasheet?

I had an exchange with the guys working with these things.
They say it's similar to the Dynex DS2101SY for which they
gave me a data sheet. I can't seem to find it on Dynex's
site, but I have a copy here:
http://cern.ch/jeroen/tmp/DYNEX_DS2101SY.pdf> (97kB).

Very interesting, 113mm dia, 79kA peak capacity. I don't
suppose it needs much reverse-voltage capability?

https://ocem.eu/en/project/particle-cern-lhc-quadrupole-dipole-diode-stacks-3/

OK, I see that, but with the low voltage drop (zero) of
a superconducting magnet, why would they need a multi-kV
reverse rating? To handle ringing after snap-off?

You need a bit of voltage to ramp up or down. It's a huge
inductor, after all. If I remember well, the power supplies
swing 200V up or down, so with a series string of 154 dipoles,
that's a little over one volt a piece. There's a tiny bit
of resistance in the interconnects as well, of the order
of 2 nOhms or so.

I don't think the kV+ reverse rating is needed, but that's
what multi-kA diodes provide.

Jeroen Belleman

 

[whit3rd]

On Friday, October 25, 2019 at 11:34:20 PM UTC-7, Jan Panteltje wrote:

On a sunny day (Fri, 25 Oct 2019 19:10:55 -0700 (PDT)) it happened whit3rd
whit3rd@gmail.com> wrote in
ae310cd2-a5ce-4287-b245-21ea874449cb@googlegroups.com>:

On Thursday, October 24, 2019 at 11:36:04 PM UTC-7, Jan Panteltje wrote:
On a sunny day (Thu, 24 Oct 2019 19:50:19 -0700 (PDT)) it happened
omnilobe@gmail.com wrote in
0762256c-11a1-496e-a294-82285ed07269@googlegroups.com>:

If you want to see electronics hardware customized for the collider
at CERN ...

It does not do anything for anybody ,

My cure:
cut budget if nothing useful comes out in a year.

What you call a 'cure', I'd call a 'disease'.
Other long-term developments: Democritus' atomic theory explaining Dalton's work with
gases, and Lilianfeld's 1925 description of the FET that came about 1960...

I have written back in sci.phisicks when it was still on topic:
"If you cannot do it with those small particles on the table top,
then you cannot do it in a machine the size of the universe."

Oh, no, scale DOES have a place. Accurate spectroscopy of dilute gasses uses the upper
atmosphere (because a small vacuum doesn't contain enough atoms to get good data),
and that kind of thing goes back a century or more. It's just not possible to make an
X-ray laser, without a linac to fill a synchrotron. You NEED relativistic energy to
do the task. The laser is tabletop size, but its power supply is an accelerator center.

> A few years later a table top accelerator was designed that could do more than CERN at that time.

Designed is easy; could it actually be built and operated? I've heard those rosy predictions,
but not success stories in follow-ups.

 

[Joseph Gwinn]

On Oct 25, 2019, Jeroen Belleman wrote
(in article <qovpc6$14gk$1@gioia.aioe.org&gt:

On 2019-10-25 16:07, Winfield Hill wrote:
Jeroen Belleman wrote...

Winfield Hill wrote:
Jeroen Belleman wrote...
Winfield Hill wrote:
omnilobe@gmail.com wrote...

The Large Hadron Collider uses big diodes in color photos.
What can you tell us about the big diodes?
The LHC superconducting bending magnets are arranged in series
strings of 154 powered by a single 13kA power supply. In the
event of a quench of one of the magnets, the diodes divert the
current around it while the whole string is ramped down.

They are bespoke 75mm diameter diffusion-type diodes. They
are clamped between two heat sinks and are kept at liquid
helium temperature.

Thanks, Jeroen. Any idea what their forward voltage drop is,
during the 13kA quenching event?

The forward voltage during a quench is of the order of 6V,
dropping rapidly as the diode heats up.

Does the diode have a part number and datasheet?

I had an exchange with the guys working with these things.
They say it's similar to the Dynex DS2101SY for which they
gave me a data sheet. I can't seem to find it on Dynex's
site, but I have a copy here:
http://cern.ch/jeroen/tmp/DYNEX_DS2101SY.pdf> (97kB).

Try<https://www.dynexsemi.com/products/semiconductors/rectifier-diodes>.

Joe Gwinn