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Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 1:30 am
by Xymox
Im getting overwhelmed with all this info...

I need to get it all put together into some easy to use form..

I think as all this is LHC related it should go in the LHC section of the portal links. This will allow quick flipping from watching Page 1 to a acronyms page for example.

So we have a "step by step" as you just described. The page should have a graphic showing the accelerators and cover the whole step by step trip from LINAC to LHC through to collisions and dump.

We have "page 1 - what it all means". This should include the page Danny252 did along with some detailed descriptions of each parameter and various modes.

We need the same thing for "LHC-OP" Vistar.

We also have a "terminology" page
We have "acronyms" page

I have someone at CERN who is in a perfect position to review and help with our work.

Any thoughts on this ?

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 1:38 am
by Xymox
Photino2, that PDF also has a nice graphic I can capture and use...

Those might be links only accessible from inside OR are just dead. They do changes things around often.. Bad links are kinda common...

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 1:42 am
by Xymox
Im going to make pages now and add the links.. Will take a while for me to do. They wont be perfect but they are better then nothing... We can fix them as we go..

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 2:41 am
by MarkyB
Hi all, I've been watching some of the experiment status views, LHCb in particular...

There are some interesting status screens accessible via the handy buttons, e.g. Page 1, LHCb Run Status, and Collimators ("Gap" is indeed around 20mm during operation as someone else suggested).

The LHC status gives quite a bit more detail than the standard Page 1 Vistar.

A really neat feature is the automatic sub-second refresh rate!

By the way, has anyone seen anything other than "This link is temporarily down. Sorry." on the Atlas status page?


Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 2:59 am
by Xymox
That LHCb link in on the portal.
ALICE status also has LHC monitoring

Yea I saw the ATLAS Status ( DCS ) for months... COOLEST thing you have ever seen...


The computer that provides this to the outside world broke.

They decided to redo everything. So whole new link addresses when its rebuilt.

ALSO its possible they may restrict it :cry:

I have argued the point of how cool it is and it should be public, but I dont know if that will work.

And it is cool... VERY cool... Nicest machine GUI of them all..

Thats MY page that says its down.. The old URL is just dead.. I will get email about the outcome and will let you know..

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 1:00 pm
by Razuul
These power point slides are quite good at explaining how the beam TVs work and a bit more info on where they are placed. ... 006-EB.ppt

Also this article has a nice picture and a bit of explanation ... -tv-c.html

I'll just keep adding links here
Short ppt with nice graphs ... tvlhc1.ppt

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 5:15 pm
by Xymox
Indeed... all good stuff. For a page in the TV these links are all great. Good images I could extract as well. But the PPT stuff is pretty easy to follow so I might just link to them during a simplified explanation of the basics of it. The pic from that news article is good.

In a few minutes of reading I do now understand the system.

Good job..

How-a-bout some of that stuff on the status-op ( LHC-OP ) page ? We need to look into that.

Re: What do the displays mean ?

Posted: Sat Nov 28, 2009 6:58 pm
by Danny252
Updated Page 1 down 2 posts

Status Op:


Re: What do the displays mean ?

Posted: Sun Nov 29, 2009 1:20 am
by Xymox


Re: What do the displays mean ?

Posted: Mon Nov 30, 2009 4:43 pm
by Danny252
Latest Page 1 - thanks to employees of CERN for their input on this version.


Re: What do the displays mean ?

Posted: Mon Nov 30, 2009 5:03 pm
by Xymox
A detailed description of PAGE 1 from the man who created Page 1 :) I will be updating out Info page shortly.

He is working on a detailed description of all the modes that Page 1 can be in and will get that up online at CERN soon.

Until then here are some handy detailed descriptions.


Fill: xzy => Integer number which increases usually every time we run the LHC through its complete cycle.

E: xyz GeV => Energy derived from 4 of the 8 main bending circuits and distributed by the LHC timing system indicating at which energy level the LHC is set. It is provided by the energy tracking system and is not necessarily reflecting the LHC beam energy.

LHC Operating mode (example: “BEAM SETUP:CIRCULATE AND DUMP”) => concatenation of accelerator mode (before colon) and beam mode (after colon) (see also:

BCT TI2/8: Beam current transformers to measure the beam intensities downstream of the 2 transfer lines TI 2 and TI8 between SPS and LHC.

I(Bx): Slow beam current transformers in each of the two LHC rings to measure the whole beam intensity (including the uncaptured beam) of the circulating beam. The signal to noise ratio is rather bad for the currently low intensities of the order of up to 5E09 per bunch/beam.

SMP flags:

Setup Beam = The intensity limit threshold as a function of energy, below which the “SET-UP BEAM FLAG” becomes TRUE, was defined as the damage limit of Cu for transient beam loss based on simulation and experimental data.

Beam Presence = The BEAM PRESENCE FLAG is TRUE when there is circulating beam in the LHC, and FALSE if there is no circulating beam. There is one BEAM PRESENCE FLAG per beam.

Movable devices allowed in and Stable Beams = In general, the LHC beam modes are not used by machine protection devices. However to derive the flags “STABLE BEAM” and ”MOVING_IN_ALLOWED” it is required to know if the beam mode is either “STABLE BEAMS” or “UNSTABLE BEAMS”. The beam mode “STABLE BEAMS” is set by operations to indicate stable beams to the experiments, which is important before switching on certain detectors.

Setup Beam: It indicates somehow the damage potential of a beam, as it is based on the combination of beam intensity and beam energy. If for a given intensity the beam energy increases (during acceleration) the setup beam flag will transit at a given energy from TRUE to FALSE. It doesn’t indicate that the LHC is being prepared for the next beam.

PM Status B1 and PM Status B2 (at bottom corner): This status indicates for each beam if the post mortem system triggering is enabled. Under certain conditions operations disables the post mortem system triggering after a beam dump, i.e. when doing inject & dump studies.

BTVs: The 2 leftmost screens shown on your image are 2 of the 4 available injection BTVs for beam 1 (clockwise circulating beam) installed in point 2 of the LHC, whereas the 2 rightmost screens are 2 of the 4 available injection screens for beam 2 (anticlockwise circulating beam). Those BTVs (as well as others installed in the LHC ring and transfer lines between the SPS and LHC) can be put in beam using different screen materials. We have screens with a Cr doped AL2O3 luminescence plate (1mm thick) and Ti foils (12 μm thick).

BTV screens: They can be moved in beam (with different screen materials, Ti or Alumina) to acquire beam profiles or out of the beam path. The exact explanation of what you see on the image on your site is difficult, but it’s most likely not beam. Attached is a screenshot where you see dumped beam 2 on the two right side screens BTVD.623458.B2 and BTVDD.629339.B2 for beam 2. The beam spot is clearly visible. I will probably remove the signals of the injection BTVs as they are not used (moved in) systematically.

Alumina screens are more sensitive and can observe single bunch beams of well below 10e9 particles. Ti-foil screens are less sensitive than Alumina screens and are usually used with higher intensity beams. The don’t perturb the beam and several of them can be inserted at the same time.

Operator comments: Text messages issued by the LHC operations team to communicate current problems, studies, activities etc. to the LHC experiments and the outside world.

CCC: CERN Control Center and the LHC landline phone numbers. The central control room at CERN was inaugurated in February 2006 and hosts all CERN accelerator operators together with the LHC cryogenics operations team and the operator surveying and controlling the technical infrastructure of CERN.

Re: What do the displays mean ?

Posted: Mon Nov 30, 2009 7:21 pm
by Xymox
I have updated the Info link under LHC to reflect all the new info and updates.

The Page 1 info is getting pretty complete

Re: What do the displays mean ?

Posted: Tue Dec 01, 2009 1:43 pm
by Danny252
Status Op has changed today!

First off the background graphs have been changed to logarithmic scales - which has lead to them making much more sense and being more readable.

Also, the luminosity reading on the top graph and integrated luminosity reading have both been replaced with BRAN Count. I believe, from a little googling, than BRAN Counts are a measure of luminosity (which is related to collision rate, if they choose to collide). But I may yet be corrected, and I have no idea what BRAN stands for!

Re: What do the displays mean ?

Posted: Tue Dec 01, 2009 5:39 pm
by Tim Bergel
I found BRAN in the acronyms list:

Beam RAte Neutrals (TAN type luminosity monitor) and TAN means Target Absorber Neutral

so yes, a type of luminosity monitor ...

Re: What do the displays mean ?

Posted: Tue Dec 01, 2009 7:33 pm
by Xymox
Oh yea,,,

I forgot to mention...

The scales, what the chart shows and even the layout of the page changes..

Log is good tho. For sure..