SPS North Area Operation Shutdown Lectures - 2006 Morning session Morning session Introduction and test beams Ilias Efthymiopoulos Afternoon session Afternoon session M2 muon beam – COMPASS Lau Gatignon Neutrino beam – CNGS Edda Gschwendtner And… PS East Area operation M. Delrieux (17 March – PM) nTOF/FTN line operation not operational in 2006
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SPS North Area Operation Shutdown Lectures - 2006 Morning session Introduction and test beams Ilias Efthymiopoulos Afternoon session M2 muon beam –
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SPS North Area Operation Shutdown Lectures - 2006
Morning sessionMorning session Introduction and test beams Ilias Efthymiopoulos
The SPS North Area was originally designed to house long-lasting experiments demands for high quality of beams: high intensity, high energy, high resolution
In the recent years most of the users are “tests” in particular of LHC detectors with permanent or “semi-permanent” BIG installations several users from astroparticle experiments
The test users have very different requirements from the big experiments: scan the full energy range ; typically [10, 300] GeV/c
with sometimes increased precision (linearity) requirements
use beams of all particle types {electrons, pions, protons, muons} with as good as possible separation and identification
and, sometimes request high (or very high) rates
and all that during the few (or even one!) week(s) of their allocated time!
Rapidly changing environment, quite demanding on beam conditions and tunes
Alternatively can be used to transport: attenuated primary beam of protons, electrons from -conversion, polarized protons for decay, enriched low-intensity beam of anti-protons, or K+
Alternatively can be used to transport: primary protons, electrons from -conversion, polarized protons for decay, enriched low-intensity beam of anti-protons, or K+
AIMAIM Additional degrees of freedom increase the flexibility in using a target station
Produce “several” secondary beams from the same target when the primary beam hits the target basically “all” the particles are produced in a
large variety of angles and energies the most energetic particles are in the forward direction
should not forget: The very intense primary proton beam has to be dumped in a controlled way
The secondary beams of the chosen momentum have to go into the directions foreseen by the beam geometry (i.e. inside the vacuum tube of each beam line)
SolutionSolution: : “wobbling” : hit the target under variable angle
Beam optics modes:Beam optics modes: High Resolution: used in the past to increase the momentum
resolution of the beam line Required additional hardware (spectrometer chambers), not available
anymore.
High Transmission: allows having the maximum particle flux at a given momentum
Filter Mode : has a focus on both planes at ~130m of the beam line, which allows using an intermediate (tertiary) target Heavily used now days to produce tertiary beams !
Tertiary beams provide more flexibility to the users and relaxes the coupling between the beam lines due to wobble choice. keep longer periods with the same wobble setting
Direct in-beam exposure should be avoided at all cases!
Hadron or electron beams containing >108 particles/burst are dangerous should be always dumped in special (thick) dumps (controlled losses)
serious irradiation to persons standing close to unshielded loss points unshielded loss points will cause excessively high radiation levels in the
experimental hall and cause dose rate limits at the CERN boundaries any in-beam exposure for even one pulse will cause observable biological damage beam line & areas should be completely shielded
Hadron or electron beams containing >106 particles/burst should be treated with respect unshielded loss points will cause limiting radiation levels in the experimental halls
and at the CERN boundaries all loss points must be completely shielded (dumps) any in-beam exposure is still serious and will cause significant administrative
Additional radiation sources in the areas Additional radiation sources in the areas
Radioactive sources Used by the experiments for their detector calibration Transport/installation under the TIS/RP responsibility Normally a garage position should be available
sometimes the source is in interlock with the area access system Warning panels at the door of the experimental areaLasers Used by the experiments for their detector calibration Normally setup certified by TIS/RPRadioactive detectors Uranium calorimeters (not anymore “a la mode”!) “hot” detectors after irradiation tests
transport/installation under TIS/RP supervision
Note Setups are modified quite often by the users
it can happen that information on the changes arrives very late
hadron/electron beams muons go through but undergo
multiple scattering ==> larger cone
Typically formed by 2-3 m of iron with at least 80cm in
each direction from the beam impact point
one or two concrete blocks (80cm each) in each direction
Several dumps can exist in a beam line provide separation between
different experimental areas motorized or build in
fixed dump at the end of each line
For high intensity beams the dump is made re-entrant, the particles are dumped into a hole, in order to reduce the particle backsplash
For very high intensities or for special beams (neutrino or muon beams) the dumps consist of many meters of iron, concrete and/or earth shielding examples: M2, P0/NA48, WANF, CNGS
The access system is used to prevent in-beam exposure for the personnel For EA can be separated in two categories: Beam lines and Experimental areas
Experimental Area Perimeter defined by concrete blocks and/or fences
typically at least 1m from the beam axis, exact shape depends on detector/installation size high intensity (>106/ppp) proton or heavy-ion beams and exp. areas are completely shielded
with concrete visibility to the area should not be blocked
Doors to access each area the main one (PPE) and at least one emergency escape door (PPX, PPG)
Several can exist in a single beam line connected to the same or different interlock chains
Access to downstream areas depend on beam conditions provided there is a dump (XTDV, XTDX, “manual”) in between
Beam Line The beam line: from the target tunnel exp.area(hall) dump A beam line can contain a single or several interlock chains of experimental areas
PPE168 – H8B Large area with four doors and a search point Big and complicated detector installations Radioactive sources, gas distribution (including flammable)
Safety ElementsSafety ElementsDoorsDoors Control the access to experimental areas and
beam lines
Users have to take a key to open the door must use the key to enter AND exit the area
At least one PPE and one PPX in each area marked at PPE xxx, PPX xxx (PPG xxx)
Door status defines the status of the area BUT NOT of the beam line free: people can enter without key key access: to enter you have to take a key beam ON/OFF: no access, beam can be
present in the area
Timeout (~1min) if a door is left open more than 1min switches
automatically to free state
In complicated areas the PPExxx door is combined with a search point acts like a door forces the area patrol to pass by that point
Access Rules to Experimental Areas One person one key
no more than 8 people at a time in the area if so, the door/area must go in free mode
Change of door/area states: free key access
search of the area by SPS operators and the GLIMOS of the experiment
key access beam (beam key access) press the end of access system
verify that the above rule was not violated via computer system
key access free via computer system door open timeout
Emergency button (“force the door”) stops the beam drops the interlock chain of the door AND the next higher level interlock chain
Dumps – Motorized XTDV, XTDXDumps – Motorized XTDV, XTDX Used to separate experimental areas in the same beam line
attached to the interlock chain of the downstream area Motorized XTDV, XTDX dumps, 2-3m of Fe Two positions defined: IN/OUT Before moving a dump the beam must be stopped
this to avoid spraying particles as the edge of the dump crosses the beam
MagnetsMagnets Power converter level
interlock on polarity current limitation
Direct measurement of the magnetic field zero magnetic field detection (“champ null”) can be very tricky if we have to transport low energy beams
Search and secure procedureSearch and secure procedure Is needed in order to switch from
Free to Key access an Exp. Area
The search is conducted by the search leader
normally the GLIMOS of the experiment and other authorized persons(s)
The defined procedure should be rigorously followed
Procedure:1. Ask all the persons present in the area to
exit and close all the doors (PPE, PPX, PPG)
2. Verify that all fences and blocks defining the perimeter of the area are in place
3. Remove all ladders or any other equipment can be used by people to climb over the fences
4. Go to the PPE door and call the PCR to switch it from “Free Access” to “Key Access”
5. Leave one person at the PPE door and start the search. All persons entering the area must take a key. Audible devices can be used during the search to warn people. Take your time and look carefully everywhere
6. If there is a “Search Box” you must re-arm it although there is a time-out to do so, don’t
rush! it is more to force you to look into that area
not just to turn the key!
7. Return all the keys to the PPE door and press the “End of Access” button
Manual VetoManual Veto “Key” to veto an interlock chain of a beam
line blocks the presence of the beam in an exp.
area, regardless the status of the existing safety elements of the chain
Normal status of all exp. area chains during shutdown
Has to be set each time there is work foreseen that can modify the status of an exp. area
Can ONLY be lifted with the agreement (signature) of the EA physicist.
The EA physicist must patrol the exp. area before signing to lift the Manual Veto verify that its perimeter is correctly closed the safety elements (dumps, doors, magnets)
are present and functionali.e. must verify that the access system can function
Changes to the access systemChanges to the access system Changes to the access system (new conditions from the users,
modification in the beam line or exp. area) are initiated and are under the responsibility of the EA physicist
The EA physicist takes care that all the parties involved are consulted and agree on the proposed changes EA and BI beam line experts access system experts, ST/MA (M. Grill) TIS/RP and AB/RSO
All modifications are discussed in the EATC meetings and documented in the minutes 1st meeting of the year: summary of all modifications during the shutdown during operation, in the meeting before the SPS period concerned