Machine Protection and Interlock Systems for the LHC

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Machine Protection and Interlock Systems for the LHC SL-Seminar Rüdiger Schmidt on behalf of

Machine Protection and Interlock Systems for the LHC SL-Seminar Rüdiger Schmidt on behalf of the MPWG The LHC challenges Powering Operation and Protection Beam Operation and Protection Seminar 11 July 2002 SLSLSeminar 11 July 2002 1

Outline u LHC parameters and layout LHC stored energy and associated risks LHC protection

Outline u LHC parameters and layout LHC stored energy and associated risks LHC protection systems u Protection and interlocks for powering u Protection and interlocks for beam operation u u u u Beam Dump Beam Cleaning Beam Loss Monitors Beam Interlock System Conclusions 2

u LHC parameters and layout LHC stored energy and associated risks LHC protection systems

u LHC parameters and layout LHC stored energy and associated risks LHC protection systems u Protection and interlocks for powering u Protection and interlocks for beam operation u u u u Beam Dump Beam Cleaning Beam Loss Monitors Beam Interlock System Conclusions 3

LHC Parameters and Challenges for Protection Momentum at collision Momentum at injection Dipole field

LHC Parameters and Challenges for Protection Momentum at collision Momentum at injection Dipole field at 7 Te. V Circumference Number of electrical circuits 7 Te. V/c 450 Ge. V/c 8. 33 Tesla 26658 m ~1700 Luminosity Number of bunches Particles per bunch DC beam current Stored energy per beam 1034 cm-2 s-1 2808 1. 1 1011 0. 56 A 350 MJ Normalised emittance Beam size at IP / 7 Te. V Beam size in arcs (rms) 3. 75 15. 9 300 µm µm µm High beam energy in LHC tunnel Superconducting Nb. Ti magnets at 1. 9 K Stored energy in magnets very large High luminosity at 7 Te. V very high energy stored in the beam power concentrated in small area 4

Energy in Magnets and Beams Drop 35 tons from 28 km Energy in the

Energy in Magnets and Beams Drop 35 tons from 28 km Energy in the magnet system: 11 GJ u In case of failure, extract energy with a time constant of up to about 100 s Energy in two LHC Beams: 700 MJ u Dump the beams in case of failure within 89 ms after dump kicker fires One beam, nominal intensity corresponds to an energy that melts 500 kg of copper Drop it from 2 km 5

Challenges: Energy stored in the magnets Energy stored in the LHC magnets, powered in

Challenges: Energy stored in the magnets Energy stored in the LHC magnets, powered in ~1700 electrical circuits - all need protection HERA: all dipole magnets store about 700 MJ LHC: to limit energy - powering in eight sectors Energy in dipole magnets (one sector): 1. 3 GJ u eight systems in the LHC - 8 dipole circuits Energy in main quadrupole magnets (one sector): 40 MJ u sixteen systems in the LHC for main quadrupoles Energy in special quadrupole magnets (6 k. A): u about 100 circuits Energy in 600 A circuits (i. e. chromaticity correction): 10 - some 100 k. J u several 100 systems 6

Energy stored in the beam [MJ] Challenges: Energy stored in the beam x 200

Energy stored in the beam [MJ] Challenges: Energy stored in the beam x 200 x 10000 courtesy R. Assmann Momentum [Ge. V/c] Energy density: even larger factor between LHC and other machines 7

The risks u Damaging equipment in case of uncontrolled release of energy stored in

The risks u Damaging equipment in case of uncontrolled release of energy stored in the magnets u u Dipole magnet replacement would take about 30 days Damaging equipment in case of uncontrolled beam losses u No realistic estimation of possible damage Magnets could quench due to beam losses, or due to other failures u Quench recovery at 7 Te. V could take several hours Beam losses due to a large variety of failures (sc magnets, resistive magnets, …) u Recovery from 7 Te. V could take hours 8

Failures of machine equipment must be anticipated Risk comes from large stored energy plus

Failures of machine equipment must be anticipated Risk comes from large stored energy plus possible failures u 7000 magnets (most of them superconducting), powered in ~1700 electrical circuits …. ~1700 power converters u Superconducting magnets operate at 1. 9 K with a small margin in temperature, at the edge of their performance u The protection of the sc elements (magnets, busbars and current leads) requires several 1000 detectors u The protection from beam losses includes more than 1000 channels (beam loss monitors and other equipment) Realistic failure scenarios => Protection systems u u u A quench in a superconducting magnet could lead to beam losses A failure of a power converter could lead to beam losses Failures in many other systems could lead to beam losses 9

LHC Machine Protection is to…. . No uncontrolled release of stored energy Priority I:

LHC Machine Protection is to…. . No uncontrolled release of stored energy Priority I: prevent damage of equipment Priority II: prevent unnecessary down-time - for example: DUMP the beam in case of beam losses that could lead to a magnet quench The Machine Protection Systems include A) Systems to protect the LHC superconducting elements in case of a quench, or others failures in the powering system B) Systems to protect the LHC equipment in case beam losses become unacceptable u …together with tools for consistent error and fault diagnostics ……. POST MORTEM 10

LHC protection systems and main interfaces Emergency Stop (AUG) Cryogenics System Warm Magnet Protection

LHC protection systems and main interfaces Emergency Stop (AUG) Cryogenics System Warm Magnet Protection Magnet System warm+cold All systems interface to control system Injection System Beam loss Monitor System Powering Interlock System Power converter System Acces system Beam Interlock System Beam Cleaning System Beam Dump System Quench Protection System Experiments Vacuum System BI RF System 11

LHC Machine Protection = Integration of systems This presentation focuses with the integration of

LHC Machine Protection = Integration of systems This presentation focuses with the integration of systems into the LHC MACHINE PROTECTION SYSTEM, … with the interlocks as glue linking systems Input from u u Superconducting Magnet tests, String 2 Accelerator Physics - Collimation - input for BEAM LOSS SCENARIOS And experience from other accelerators u SPS, LEP, HERA, RHIC and FERMILAB 12

How did it start…. u Some Systems for Machine Protection were already in the

How did it start…. u Some Systems for Machine Protection were already in the baseline: Quench Protection (LHC-ICP), Beam Dump (SL-BT), Beam Losses (SL-BI), Beam Cleaning (J. B. Jeanneret, SL-BI) … u Machine Protection WG started in March 2001, R. Schmidt and J. Wenninger (chairman, scientific secretary) - reports to LCC u Interlock System: Architecture of Interlock Systems, LHC Project Report 521, (F. Bordry et al. ), System done in SL-CO, B. Puccio u Autumn 2001 Beam Cleaning Study Group (BCSG, chairman R. Assmann): “Study beam dynamics and operational issues for the LHC collimation system. Identify open questions, assign priorities, and show the overall feasibility of the LHC cleaning system. “ Reports to LCC and works in close collaboration with MPWG This presentation is on behalf of the MPWG - and many other colleagues that contributed to the work (in particular in the Beam Cleaning Study Group) 13

…. . where should it go - be ready in time From now to

…. . where should it go - be ready in time From now to 2006 Fabrication of equipment Installation of completed components Very thorough commissioning of the hardware systems starting in 2005, sector by sector, as key for successful fast start up with beam, throughout 2005 and 2006 In 2006 - one beam injected and transported across two sectors (hopefully - requires operation of SPS ) Start-up with two beams in spring 2007 14

Layout of the LHC ring: 8 arcs, and 8 long straight sections RF +

Layout of the LHC ring: 8 arcs, and 8 long straight sections RF + Beam instrumentation Momentum Cleaning WARM Beam dump system One sector = 1/8 Betatron Cleaning WARM 15

u LHC parameters and layout LHC stored energy and associated risks u Protection and

u LHC parameters and layout LHC stored energy and associated risks u Protection and interlocks for powering u Protection and interlocks for beam operation u u u Beam Dump Beam Cleaning Beam Loss Monitors Beam Interlock System Conclusions 16

LHC Powering in 8 Sectors Powering Sector COLD (<2 K) 2. 9 km 5

LHC Powering in 8 Sectors Powering Sector COLD (<2 K) 2. 9 km 5 WARM 500 m 4 6 Octant DC Power feed 3 DC Power Main Arc FODO cells main dipoles, quadrupoles, chromaticity sextupoles, octupoles 7 tuning and orbit correctors, skew quadrupoles, spool pieces LHC 27 km Circumference 8 2 Sector Slide from P. Proudlock 1 Continuous Cryostat / Cryoline Superconducting bus-bars run through cryostat connecting magnets. Current feeds at extreme ends. End of Continuous Cryostat dispersion suppressors, Some of the matching section, and the electrical feedbox. Other central insertion elements eg. Low Betas, separator dipoles, matching 17

Separation of Protection systems With respect to operation of the POWERING system: Energy stored

Separation of Protection systems With respect to operation of the POWERING system: Energy stored in magnets of one cryostat u Electrical circuits in one continuous cryostat independent from circuits in other cryostats With respect to operation with BEAM: Energy stored in beams u Two systems - one BEAM DUMP SYSTEM for each beam 18

POWERING ABORT POWERING u Detect quenches or other failures u Energy stored in magnets

POWERING ABORT POWERING u Detect quenches or other failures u Energy stored in magnets to be safely deposited with POWER DUMP SYSTEM (Energy extraction) EDF Magnet Energy Magnets Cryogenics 500 ms Extraction Resistors 2 min BEAM ABORT BEAM OPERATION u Detect dangerous failures or beam losses u Energy stored in beams to be safely deposited with BEAM DUMP SYSTEM SPS + RF Beam Energy LHC Experiments 10 h Magnets / Cryogenics 10 h Collimation system 0. 1 -10 h Beam Dump 89 s Back to EDF Dump Trigger 19

Example: Protection main dipoles When conditions are OK - green light for powering In

Example: Protection main dipoles When conditions are OK - green light for powering In case of a failure (quench), uncontrolled release of energy is prevented: Fire quench heaters (quenched magnets) Current by-passes magnet via power diode Extract energy by switching a resistor into circuit - eight tons of steel heated to 300 °C Switch off dipole power converter, and possibly others Release helium by safety relief valve 13 k. A switches from Protvino Russia K. Dahlerup-Petersen (LHC-ICP) 20

Example for architecture in one LHC sector - powering subsectors 21

Example for architecture in one LHC sector - powering subsectors 21

Results from the String u String 2: commissioning of Powering, Magnet Protection and Powering

Results from the String u String 2: commissioning of Powering, Magnet Protection and Powering Interlocks successfully in 2001 and 2002 l String 2 gave us confidence as we observed a smooth commissioning of the powering protection systems l Complexity of powering systems for String 2 are similar to one of the LHC Powering Subsectors => scaling to the LHC is reasonable R. Saban and the String Team 22

u LHC parameters and layout LHC stored energy and associated risks u Protection and

u LHC parameters and layout LHC stored energy and associated risks u Protection and interlocks for powering u Protection and interlocks for beam operation u u u Beam Dump Beam Cleaning Beam Loss Monitors Beam Interlock System Conclusions 23

Machine protection when operating with beam u Early commissioning: First injection of beam into

Machine protection when operating with beam u Early commissioning: First injection of beam into the LHC u Regular injection into the LHC u At 450 Ge. V During the energy ramp u u u At 7 Te. V - before squeezing At 7 Te. V - after squeezing Operation with beam is discussed in the LHC Commissioning Committee (LCC) - chaired by S. Myers, scientific secretary O. Brüning 24

Beam intensities Intensity range ~ 1: 60000 !! Energy of LEP beam 25

Beam intensities Intensity range ~ 1: 60000 !! Energy of LEP beam 25

Machine protection: Beam energy For 7 Te. V: u fast beam losses between 106

Machine protection: Beam energy For 7 Te. V: u fast beam losses between 106 and 107 protons could quench a dipole magnet u fast beam losses with less intensity than one “nominal bunch” could already damage superconducting coils u slow regular losses could quench the magnets Quench limits: J. B. Jeanneret, D. Leroy, L. Oberli and T. Trenkler, LHC Project Report 44, 1996 Requirements and Design Criteria for the LHC Collimation System, R. W. Assmann et al. , EPAC 2002 and Project Note 277 26

Machine Protection Systems must be operational Beam Dump System u The beam dump block

Machine Protection Systems must be operational Beam Dump System u The beam dump block is the only element that can stand the full 7 Te. V beam without damage Beam cleaning system (collimators) u u u Capture particles with collimators in the warm insertions, with an efficiency of > 99. 9%, to minimise losses in superconducting magnets For equipment failure, collimators are the first to capture beam losses Collimator position adjustment is critical Beam Loss Monitor System u Measures beam losses and, possibly triggers a beam dump Beam Interlock System u “Green Light” for beam operation, if changes to red => BEAM DUMP Post Mortem recording must be operational u Working Group on Post Mortem, chaired by J. Wenninger 27

Beam “lifetime” for optimum operation u During “healthy” operation with nominal luminosity the lifetime

Beam “lifetime” for optimum operation u During “healthy” operation with nominal luminosity the lifetime is determined by the collision of two protons (beam lifetime in the order of 20 hours) u A large fraction of the protons is “lost” in the high luminosity collision points - and into ATLAS and CMS (corresponds to 10 k. W per experiment) u At the end of the fill or in case of failure - the residual beam will be dumped, and its energy will end in the beam dump blocks 28

Lifetime of the beam with nominal intensity at 7 Te. V Beam lifetime Beam

Lifetime of the beam with nominal intensity at 7 Te. V Beam lifetime Beam power into equipment (1 beam) Comments 100 h 1 k. W Healthy operation 10 h 10 k. W Operation acceptable, collimation must absorb large fraction of beam energy (approx. = cryogenic cooling power at 1. 9 K) 1 h 100 k. W Operation only possibly for short time, collimators must be very efficient 1 min 6 MW Equipment or operation failure - operation not possible - beam must be dumped Acceptable lifetimes worked out by Beam Cleaning Study Group - see reports 29

Lifetime of the beam at 7 Te. V Beam lifetime 1 s Comments Failure

Lifetime of the beam at 7 Te. V Beam lifetime 1 s Comments Failure of equipment - beam must be dumped fast 15 turns Failure of D 1 normal conducting dipole magnet - monitor beam losses, beam to be dumped as fast as possible 1 turn Failure at injection, failure of beam dump kicker, or injection kicker misfiring with stored beam, potential damage of equipment, protection relies on collimators Comments: The parameters at injection energy of 450 Ge. V are much more relaxed Specification for the BLMs, J. B. Jeanneret+H. Burkhardt in the BISpecification Committee Very fast losses due to failures of the dump systems, LHC Project Note 293, R. Assmann, B. Goddard, E. Vossenberg, E. Weisse - not discussed here 30

Though the LHC cycle: First injection into the LHC Early commissioning: first injection into

Though the LHC cycle: First injection into the LHC Early commissioning: first injection into the LHC with low intensity beam would neither quench magnets nor damage equipment (pilot bunch with about 5 · 109 protons) u u Establish circulating beam Commission beam monitoring and other systems Commissioning of beam dump system Possibly first energy ramp with pilot bunch Protection against beam losses is not required …but it needs to be certain that beam intensity is low, at top energy collimators should be in “coarse” position 31

Regular injection - consider the first turn There about 7000 magnets powered in ~1700

Regular injection - consider the first turn There about 7000 magnets powered in ~1700 electrical circuits, >100 collimator jaws, more than 100 vacuum valves, roman pots…. Example: magnet has wrong setting (Power Converter fault, or Power Converter has wrong input) • The beam is deflected during the first turn • The beam touches / traverses the vacuum chamber • The beam hits equipment (magnet, collimator, experiment, . . . ) u u u Low beam intensity (pilot bunch, 109 - several 1010) - no problem Beam intensity is above about 1010 - quenches of sc magnets Beam intensity is much higher, up to 2· 1013 - equipment could be damaged see J. B. Jeanneret et al. Experience from SPS - injected beam hits UA 2, could happen for LHC (studies by W. Herr): NOT TOLERABLE FOR LHC 32

LHC ring with several 1000 objects that could prevent the beam from circulating (magnets,

LHC ring with several 1000 objects that could prevent the beam from circulating (magnets, mechanical objects, …) If beam is already circulating, injected beam will survive Any relevant failure would prevent the beam from circulating In principle, one proton for checking would be sufficient - in practice 1010 - 1011 are more practical 33

How to avoid damage at injection No beam is circulating u In case of

How to avoid damage at injection No beam is circulating u In case of equipment failure condition - no injection u Injection of intense beam NOT ALLOWED (interlock) Step 1: Injection of weak beam <1011 protons - ALLOWED Step 2 A: If beam circulates - request injection of intense beam Step 2 B: JUST BEFORE INJECTION check if circulating beam is OK Step 3: Injection of beam with higher intensity, ONLY, if beam is still present u If there is no circulating beam => no injection => go back to step 1 u If there is circulating beam - inject beam => go to step 2 u If there is a bunch present at the longitudinal position of the fresh beam to come in, it will be deflected into the TDI - go to step 2 34

Replacing pilot beam by batch from SPS Injection failures have been worked out by

Replacing pilot beam by batch from SPS Injection failures have been worked out by the Injection WG and the BT-Group - led to proposal for TDI 35

Beam Dump System The beam is dumped, either due to an operator request, or

Beam Dump System The beam is dumped, either due to an operator request, or by the beam interlock system after a failure has been detected u The beam dump system has many active components - kicker magnets, septum magnets, dilutor - all need to ramp with beam energy u The beam dump is an active system - it requires a trigger to dump the beam u Quality and reliability of the beam dump system can not be better than the quality and reliability of the trigger From SL-BT, E. Carlier 36

Requirement for clean beam dump Beam dump must be synchronised with particle free gap

Requirement for clean beam dump Beam dump must be synchronised with particle free gap Strength of kicker and septum magnets must match energy of the beam « Particle free gap » must be free of particles 37

Requirement for clean beam dump Depending on the beam intensity in the gap, particles

Requirement for clean beam dump Depending on the beam intensity in the gap, particles would be sprayed I) Rigorous synchronsation II) Additional collimators 1) Strength of kicker and septum magnets must match energy of the beam The entire beam would be deflected with an angle that does not correspond to the nominal angle Beam Energy Tracking using special hardware BEAM ENERGY METER « Particle free gap » must be free of particles About 100 bunches would be deflected with an angle between 0 and the nominal kick I) Cleaning of particle free gap (active and passive) II) Monitoring of beam intensity - if too large- dump beams Beam dump must be synchronised with particle free gap 1) TCDQ - suggested by SL-BT, and LHC Project Note 297 38

Beam Energy Meter and beam dump system Energy tracking required locally in insertion 6

Beam Energy Meter and beam dump system Energy tracking required locally in insertion 6 for the beam dump system: u u u u Extraction kicker Septum magnets Dilution kickers The field of the septa magnets needs to track the beam energy within about +-0. 5 % The dump kickers need to track the beam energy It is required to apply trims to the extraction trajectory M. Gyr, J. B. Jeanneret Distribution of energy information to Beam Loss Monitors around the ring (how…? ) 39

Safe tracking that allows trimming of the functions in the beam dump system in

Safe tracking that allows trimming of the functions in the beam dump system in a limited range Current for the magnet with standard power converter / standard control electronics with a current versus time function loaded into the controller During the energy ramp the deflection angle is constant. The non-linearity between current of the power converter and magnetic field is taken into account in the definition of the ramp function (as for all other magnets) This is not sufficient for such critical system, therefore… Reliable monitoring for safe operation is required 40

Dipole magnets Sector 5 -6 Sector 6 -7 DCCT Beam Energy Meter Other users

Dipole magnets Sector 5 -6 Sector 6 -7 DCCT Beam Energy Meter Other users Energy consistent DCCT Beam Energy Meter Make energy Beam Energy Meter DCCT Septum magnet beam 1 Beam Energy Meter Energy not consistent Dump beam DCCT Septum magnet beam 2 Prototyping components for Energy Meter has been made by J. Pett et al. 41

Beam Cleaning System Collimators close to the beam are required during all phases of

Beam Cleaning System Collimators close to the beam are required during all phases of operation • Sophisticated beam cleaning system with many collimators has been designed (J. B. Jeanneret, and EPAC 2002 presentation by BCSG - R. Assmann) - limit aperture to about 6 -10 s • Together with the Beam Loss Monitors produce a fast and reliable signal to dump the beam if beam losses become unacceptable 42

56. 0 mm +- 3 1. 3 mm Beam +/- 3 sigma Beam in

56. 0 mm +- 3 1. 3 mm Beam +/- 3 sigma Beam in vacuum chamber at 7 Te. V 43

56. 0 mm Example for failure at 450 Ge. V Ralphs EURO 16. 0

56. 0 mm Example for failure at 450 Ge. V Ralphs EURO 16. 0 mm Beam +/- 3 sigma and orbit corrector 10 % / 100 % of Imax 12. 0 mm Assume that the current in one orbit corrector magnet is off by 10% of maximum current (Imax = 60 A) 44

56. 0 mm Collimators at 7 Te. V, squeezed 1 mm Ralphs EURO +/-

56. 0 mm Collimators at 7 Te. V, squeezed 1 mm Ralphs EURO +/- 8 sigma = 4. 0 mm Beam +/- 3 sigma Example: Setting of collimators at 7 Te. V - with luminosity optics Beam must always touch collimators first ! Collimators might remain at injection position during the energy ramp 45

Particles that touch collimator after failure of normal conducting D 1 magnets After about

Particles that touch collimator after failure of normal conducting D 1 magnets After about 13 turns 3· 109 protons touch collimator, about 6 turns later 1011 protons touch collimator 1011 protons at collimator “Dump beam” level V. Kain 46

Beam Loss Monitors Primary strategy for protection: Beam loss monitors at collimators continuously measure

Beam Loss Monitors Primary strategy for protection: Beam loss monitors at collimators continuously measure beam losses u Beam loss monitors indicate increased losses => MUST BE FAST After a failure: u Beam loss monitors break Beam Permit Loop u Beam dump sees “No Beam Permit” => dump beams In case of equipment failure, enough time is available to dump the beam before damage of equipment - including all magnets and power converters - but issues such a General Power Cut etc. are still being addressed Failure scenarios with circulating beam studied by O. Brüning, and V. Kain Beam Loss Monitor System: Specifications by BI-Spec-Committee (JBJ+HB), and realisation of the system by B. Dehning et al. in SL-BI 47

Redundant strategy for protection in case of equipment failure u u Beam loss monitors

Redundant strategy for protection in case of equipment failure u u Beam loss monitors around the LHC machine (a subset of all BLMs is critical for protection - to be defined) Detection of fault states from equipment (e. g. power converter) Example: Power converter failure of D 1 separation dipole induces orbit distortion Þ Signal from Powering Interlock System to Beam Interlock System to DUMP BEAM OR Þ u Signal from Beam Loss Monitors to Beam Interlock System to DUMP BEAM What to include to generate Beam Abort - to be worked out later (some flexibility required, the system must be tuned to optimise operational efficiency) 48

Architecture of the BEAM INTERLOCK SYSTEM 49

Architecture of the BEAM INTERLOCK SYSTEM 49

BEAM INTERLOCK CONTROLLER p. 5050

BEAM INTERLOCK CONTROLLER p. 5050

General Layout of the 2 Machine Interlock Systems Control Room B. Puccio 51

General Layout of the 2 Machine Interlock Systems Control Room B. Puccio 51

Quantifying reliability for the LHC u u Reliability can be quantified - with accepted

Quantifying reliability for the LHC u u Reliability can be quantified - with accepted mathematical tools. Such tools are challenging since mathematics involved can be rather advanced Reliability of different systems can be compared To estimate the reliability of the entire accelerator, the reliability of all subsystems need to be estimated Strictly required for systems related to safety of personnel (INB, legal obligation) u Should be extended to equipment protection systems u … and for other systems in order to optimise the efficiency of LHC operation u Examples of past studies: quench protection system, interconnects between magnets, SPS access system, … 52

u LHC parameters and layout LHC stored energy and associated risks u Protection and

u LHC parameters and layout LHC stored energy and associated risks u Protection and interlocks for powering u Protection and interlocks for beam operation u u u Beam Dump Beam Cleaning Beam Loss Monitors Beam Interlock System Conclusions 53

Conclusions u The LHC is a global project with the world-wide highenergy physics community

Conclusions u The LHC is a global project with the world-wide highenergy physics community devoted to its progress and results u As a project, it is much more complex and diversified than the SPS or LEP or any other large accelerator project constructed to date From the summary of the LHC Machine Advisory Committee in March 2002, chaired by Prof. M. Tigner I consider the complexity of the LHC with its magnets systems at 1. 9 K and the machine protection issues to be the main challenges for the LHC 54

Conclusions u u If the protection systems will not be fully operational for Hardware

Conclusions u u If the protection systems will not be fully operational for Hardware commissioning in 2005 and Beam commissioning in 2007 - there is no way to startup the machine Very good progress for the protection against uncontrolled release of magnet energy, due to the excellent collaboration of people and the experiments at the String - a sound baseline has been established For the protection against beam losses still substantial work ahead of us - in particular for fast losses - to avoid any damage of collimators or other machine equipment (work ongoing in BCSG and MPWG, LCC is the coordinating body) For several important sub-systems principles and the architecture has been established - but the technical work is hampered by lack of personal and responsibilities need to be defined Renovation of SPS interlocks - possibly with the same brainware and hardware (J. Wenninger & R. Giachino + B. Puccio & myself) 55

Acknowledgement u This presentation is based of the work of many people u Particular

Acknowledgement u This presentation is based of the work of many people u Particular thanks to my colleagues in the MPWG, and its scientific secretary J. Wenninger u Particular thanks also to my colleagues in the Beam Cleaning Studies team, to its chairman R. Assmann, and to the “father of LHC collimation” J. B. Jeanneret u References under: http: //www. cern. ch/lhc-collimation/ http: //www. cern. ch/lhc-mpwg/ Future related presentation could be on Beam Cleaning, Beam Loss Monitoring, Beam Dump System, Quench Protection System and Post Mortem System 56