The commissioning of the LHC: first the technical systems, then the commissioning with beam

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1 The commissioning of the LHC: first the technical systems, then the commissioning with beam Roberto Saban 4. Ulusal Parçacık Hızlandırıcıları ve Uygulamaları Kongresi 30 Ağustos 1 Eylül 2010, Bodrum - Türkiye

Specificity and complexity of the LHC Superconducting magnet system Superconducting RF Eight independent sectors Large or very large distances number of electrical circuits energy stored in the

2 Specificity and complexity of the LHC Superconducting magnet system Superconducting RF Eight independent sectors Large or very large distances number of electrical circuits energy stored in the magnetic system high-tech superfluid helium production plants unprecedented resolution power converters number of infrastructure systems Coupling between systems Systematic approach which ensures completeness, repeatability, traceability. 2

Courtesy Serge Claudet the layout of the cryogenic system 8 x 18kW @ 4.

3 Courtesy Serge Claudet the layout of the cryogenic system 8 x 4.5 K superconducting magnets 24 km & K K 150 t He inventory eight independent sectors 3

4 Courtesy Serge Claudet the architecture of the cryogenic system A large variety of large scale refrigerators A large variety of valve boxes and large distance lines 50% of the world s helium liquefaction capacity The largest cryogenic system ever built 4

5 Courtesy Serge Claudet P [kpa] the cooling scheme SOLID HeII Pressurized He II λ line HeI CRITICAL POINT GAS Heat inleak: ( 1W/m) 10 1 Saturated He II 1 10 T [K] vacuum vessel 5

the cryogenic system Cryogenic plants of unprecedented capacity (20 kw at 4.5 K) and including main components at the frontier of today s technology (cold compressors for the 1.

6 the cryogenic system Cryogenic plants of unprecedented capacity (20 kw at 4.5 K) and including main components at the frontier of today s technology (cold compressors for the 1.8 K refrigeration unit) Full scale validation of cooling scheme (cool down and warm ups, quench recovery, redundancy) Cryogenic circuit integrity DFB & CL Instrumentation Leak tightness Insulation vacuum Commissioning of the complete cryogenic system 6

7 the electrical circuits of one sector 1.9 K 4.5 K 1.9 K 4.5 K 13 circuits 14 circuits 157 circuits 6 circuits Totalling 190 circuits 7

8 the electrical subsectors 8

the inventory of electrical circuits Sector Circuit Type 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-1 LHC 13 ka 3 3 3 3 3 3 3 3 24 Independently Powered Dipoles 3 2 2 3 1 0 2 3 16 Independently Powered

9 the inventory of electrical circuits Sector Circuit Type LHC 13 ka Independently Powered Dipoles Independently Powered Quadrupoles A with Energy Extraction A Energy Extraction in Converter A no Energy Extraction A Correctors TOTAL Sector Circuit Type LHC 60A Closed Orbit Correctors

10 automation of procedures Approved and reproducible test sequences Assistance to operators Automatic recording of test results 10

11 computer assisted analysis 11

12 quality control Automated recording but also manual data entry Provides data for analyis tools Ensures perennity of data 12

12 GJ per sector today 290 MJ The large magnetic energy (1.

13 154 dipoles the superconducting magnet system the dipole circuit Circuit inductance 16 H Energy stored at nominal current ( A) is 1.12 GJ per sector today 290 MJ The large magnetic energy (1.12 GJ) stored in the magnets of one sector (2.5 x Hera) requires extremely reliable systems to detect failures and safely dump the energy in a controlled way 13

up Tracking Inner triplet 2ppm Power converters with

14 the power converters Regulation loop Free-wheel system at nominal current with high time constant Compatibility with QPS at start up Tracking Inner triplet 2ppm Power converters with unprecedented precision (a few ppm) over a very large dynamic range (10 4 ) 14

15 Courtesy Reiner Denz 1. symmetric quenches 2. splice resistance the quench detection system U_splice the dipole circuit if (U_1+U_2) > 100mV during 10ms then trigger quench heaters 15

16 Courtesy Reiner Denz symmetric quenches cables 240 km individual cables 4400 connectors errors permitted if (U MB1 > U MB2 ) & (U MB1 > U MB3 ) & (U MB1 > U MB1 ) then trigger MB1 quench heaters 16

17 an assembly defect in a splice + 17

18 the collateral damage Insulation vacuum subsector 18

19 the lessons learnt the measures which were taken An improvement of the quench detection system was put in place. It generates both early warnings and interlocks, and it encompasses magnets, bus bars and interconnects. The relief devices on the cryostat vacuum vessels were increased in discharge capacity and in number, so as to contain a possible pressure rise to below 0.15 MPa absolute even in presence of an electrical arc. The external anchoring of the cryostats at the locations of the vacuum barriers were reinforced to guarantee mechanical stability. The personnel access rules during powering were re-examined, to further exclude human presence not only in the machine tunnel, but also in the neighbouring caverns and technical areas underground. 19

20 Courtesy Lucio Rossi the shutdown 20

Courtesy Matteo Solfaroli-Camillocci 2008 better quicker but at a lower current level from to days April 1 st September 10 th 164 Shifts Morning Afternoon Night 124 124 3 but re-commissioning More

21 Courtesy Matteo Solfaroli-Camillocci 2008 better quicker but at a lower current level from to days April 1 st September 10 th 164 Shifts Morning Afternoon Night but re-commissioning More automated and powerful software tools Increased stability of cryogenic system More complex procedures for the main circuits More constraining safety measures 2009 from to days August 21 st November 18 th 89 Shifts Morning Afternoon Night

22 the superconducting circuits but also all the other systems the RF system the beam dumping system the warm magnets the injection systems the collimators the beam instrumentation 22

23 and the infrastructure systems Cooling stations (raw, demineralised water, C 3 F 8, C 6 F 14 ) 150 Pipelines for all the water circuits Cooling towers (450 MW) 22 Chilled water stations 6-12 C (73 MW) km Water network: 3 pumping stations m 3 /h Equivalent to small city of a population of % Geneva s water consumption water distribution and cooling system 23

120 000 m 3 /h each 800 points Compressed air Demineralised water production 20

24 and the infrastructure systems ventilation, air conditioning, etc. Heating, ventilation, air conditioning Fire fighting units from to m 3 /h each 800 points Compressed air Demineralised water production 20 m 3 /h km m 3 /h Eurotunnel LHC stations 200 km network 0.1 μs/cm 24

25 and the infrastructure systems French source 400 kv / 490 MVA electricity distribution Transmission 66 kv Distribution 18 kv Consumption 1016 GWh/year = ⅙ of Geneva Distribution 18 kv Instantaneous Distribution power 180 MW 18 kv= ½ - ⅓ of Geneva 25 Swiss source 130 kv / 156 MVA More than kv feeders Tens of thousands of LV feeders

26 Technologies at or beyond the state of the art... in summary Superconducting magnets operating close to the limit of the load line Cryogenic plants of unprecedented capacity (18kW at 4.5K) and including main components at the frontier of today s technology (cold compressors at 1.8K) Power converters with unprecedented precision (a few ppm) over a very large dynamic range (104) Each sector stores a large magnetic energy (1.2 GJoule) in the magnets (2.5 x Hera) and therefore requires extremely reliable systems to detect quenches and safely dump the energy in a controlled way 26

27 ... in summary High tech components in industrial quantities (1800 circuits, large circuits 154 dipoles, 16 H, 12kA) which justify methodology for test procedures, automation of procedures and analysis quality control Standard technologies in infrastructure systems (electrical, ventilation, water cooling, networks, fieldbuses, control infrastructures, etc.) in large quantities, various types and stretching over large distances 27

28 Coupling and interdependencies of the systems... in summary complexity for the diagnostics (quantity of signals, spread over different systems ) & instrumentation (voltage taps, current sensors, heaters, flow meters, cryogenic instrumentation, etc.) interdependency for safe operation (interlocks, QPS, PCs but also cooling, ventilation, AC distribution normal, UPS, safety network) Geographical distribution which extends the size of the installation (e.g. cryogenics: surface buildings 50 x 50 m, shafts 100 m deep, tunnel 2 x 3 km long) 28

29 29

LHC MACHINE PROTECTION

LHC MACHINE PROTECTION Rossano Giachino, CERN, Geneva, Switzerland Abstract The energy stored in LHC magnets presents a considerable challenge for commissioning even before any beam is injected. Furthermore,