Instructions for shifters

SPS status

Always check the SPS status on the Vistars SPS page 1 web page or on the Monitor in the top right side of the Control Room. The white line gives the status of SPS magnets, the yellow line shows the particle intensity in the SPS. Decrease of the yellow line means extraction to experimental areas. Flat lines mean beam.


Below the graphics, you see the intensity on targets. Our target is T2, normal intensity is around 30 E11, Multiplicity > 0 and Symmetry > 80%. Comments/warnings from SPS operators are shown in the bottom right corner of the monitor. In case of problems with beam, a report on the problem and actions taken, as well as a time estimation (as soon as it's available) for when beam will be back will appear in the same spot.


What to do

  • Monitor the presence of beam spills sent to T2 (and/or rely on the bip sound heard in the control room). If beam goes away, check the monitor for information from operators and report the beam loss, causes, actions and time estimation in the e-log.

  • If beam will be away for an extended period of time (i.e. about an hour or more) stop the current run and start a new one labeled "cosmic". When beam will be back, stop the cosmic run and start a new physics run.

  • If beam is away for an extended period of time and no information is shown on the beam monitor, call the Cern Control Center (CCC) (number on the monitor and in the Expert Contact List) and kindly ask about the situation (remember to identify yourself as the NP04 shifter on the H4 beamline).

Alarms and other sounds

The NP Hall is equipped with many radiation monitors (radiation protection system) to make sure that the dose rate inside the hall is always under the Supervised Radiation Areas threshold. Normally, the radiation level is below this threshold, and the monitors have a green light. Very sporadically, it can happen that for different reasons related to beam set-up, the radiation level slightly increases and one or more of the monitors are triggered. For your knowledge, all working spaces in the hall have the thresholds set to:

  • 3 uSv/h orange alarm (pre-alarm)
  • 6 uSv/h red alarm (cut of the beam)

In this document you can find a guideline that will help you react in case one of the ambient radiation monitors is triggered and also useful contacts that could give you explanations in that case.If you hear the radiation alarms:

If you hear a sound like a pressure might well be one Cherenkov lowering its pressure: check in CESAR (see below) in the Thresholds section

Beam line check and control: CESAR

H4-VLE beam status and control is accessible from the CESAR system. A PC dedicated to this is installed in the control room, immediately on the right when entering from the Lausanne door. General CESAR instructions are available.

The PC is set up to automatically login with the correct user and privileges. If CESAR is not running, right-click anywhere on the screen, then left-click on CESAR. From the interface, you can visualize the status of all beam components, and change some of the parameters. Components can be reached clicking on one of the icons in the top row. The name is visualized when passing the mouse over them.

NB: If there already are open windows with a large red band on the upper part, values in the windows are not updated. Close these windows or click on the Refresh button to update them.

Components are identified by a component name, a beamline identifier (022 for H4), a number giving the distance in metres from the primary target. Our target is at 680m from the primary target.

Components are also grouped in tabs on the very top of the GUI.

Check trigger rate

Click on the "scalers" icon , the one with small numbers in the instruments group. (or: Detectors-->Scaler status) EXPT.NP04.012 gives the number of triggers per spill.

Same number is also in the Triggers section, under General Trigger

Normal trigger rates per spill with collimator fully open and about 8E5 particles /spill on XSCI.022.680 (Detectors--> Triggers) should be around :

1 GeV/c 2 GeV/c 3 GeV/c 4 GeV/c 5 GeV/c 6GeV/c 7 GeV/c
150 200 300 900 1100 1200 1400

These numbers can vary a bit depending on SPS conditions, number of particles on T2. and collimator opening

You can also check the number of particles on our target, (pot) in the Detectors--> Triggers

XSCI.022.680 is the detector just before the target. should count about 8 or 9 10E5 particles

If any of the above parameters is ( SPS, pot, trigger) is abnormal, please log in elog. If the situation persists, check instructions for "no beam" , or call an expert.

Check/ set Cherenkov pressure

From the "Threshold" icon (looks like a PMT)

High pressure (HP) Cherenkov: XCET713

Low pressure (LP) Cherenkov: XCET716

Settings and expected trigger rates in xcet_settings.xlsx

P 1 GeV/c 2 GeV/c 3 GeV/c 4 GeV/c 5 GeV/c 6GeV/c 7 GeV/c
HP 0 (8) 0 3.5 2.5 ? 9 7
LP 1 1 1.2 1 2 1.5 1.5

How to start/stop the beam

Go to the Access command page,

Select Door 164

Click on Open to stop the beam

Click on Beam to get the beam

You will be asked for usename and password. Enter your *CERN account Username and Password *

Wait for all elements to be in the correct status (will be notified). In case of problems, look at instructions in the No Beam section below

How to change the beam energy

Click on the "folder" Icon

A list of beam files will appear

Do not consider the ones in red

Choose the one with the desired value of the Intermediate Energy

Click on the Load Beamfile button on the bottom of the page

Click on "Yes" in the next two popup windows (one of them contains warnings, it's ok)

Wait and see.

Collimators, intensity, alarms

We can "play" with two of the collimators to tune the intensity of the beam, in the "Collimators" icon/tab. The intensity upstream our targer can be incresed/reduced with the XCHV.022.130 collimator.

This collimator can be useful to reduce intensity if the radiation warning on NP02 sounds, or to increase intensity in case we get a low number of spills. This because the radiation monitors are sensitive to levels integrated oveer cycles.

The trigger rate can be incresed/decreased with our collimator, XCSH.022.694. Opening it increases the trigger rate but increses the momentum spread.

From the "Collimators" icon/tab, choose the one to change Click on Jaws openings set the value (mm) always the same for the two jaws

always a negative and a positicve one

click on OK

In case there is no beam to NP04 (if you do not see any trigger but there is beam sent to T2 target:)

Check the various beam elements from CESAR, as in the list below. When a beam element is not in the reference position/value it is marked in red, it can be reset by clicking on set to reference or Move (depending on the element) Warning: if a menu pops up with "change beam reference" ticked untick it!
  • Check that the doors are closed. From the Access status icon, look at doors 174, 184, 164 ( the last ones in the list). Check that they are closed. If some need Patrol..find a person with Patrol rights (Letizia, Paola. Filippo, Stefania, Roberto).
  • Check in the comments line that the beam file is the correct one
  • Check that the target is in. Target is in the Obstacles section, the one at 680 metres. Should be either Copper (for beam momentum >3 GeV/c) or Tungsten (below). If it is not in, click on Move and choose.
  • Check that the TAX are out
  • Check that the TDV are out, except the last one that is broken
  • Check the magnet currents
  • Check the collimator status
  • If nothing the expert!

-- PaolaSala - 2018-09-01

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng BeamInfo.png r1 manage 1065.8 K 2018-09-05 - 16:47 RobertoAcciarri  
PDFpdf Radiation_Alarm.pdf r1 manage 17.4 K 2018-10-22 - 17:19 PaolaSala Radiation alarms
PNGpng SPSBeam.png r1 manage 1086.5 K 2018-09-05 - 16:42 RobertoAcciarri  
Unknown file formatxlsx xcet_settings.xlsx r1 manage 18.9 K 2018-10-11 - 12:42 PaolaSala settings and triggers fox Cherenkovs
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