Linac4 at CERN

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Linac4 at CERN Powered By Docstoc
					Plans for the upgrade of the CERN
 complex of proton accelerators
                       R. Garoby

                         Content

   Introduction (European Strategy & CERN white paper)
   Scenarios for the upgrade of the accelerators
   Linac4
   SPL & PS2
   Roadmap
   Summary
        Introduction
        INTRODUCTION




R. G.        2     IDS meeting - CERN – 29 March 2007
        Statement of the European Strategy Group (1/2)




                                                    Consolidation
                                                    and upgrade of
                                                       injectors




                                                     LHC upgrade
                                                     and maximum
                                                      performance
                                                        injectors




R. G.                          3           IDS meeting - CERN – 29 March 2007
        Statement of the European Strategy Group (2/2)


                                                      R & D for
                                                     LHC upgrade
                                                     and n facility




                                                      preparation
                                                       for n facility




R. G.                          4           IDS meeting - CERN – 29 March 2007
                                                       Submitted for information and discussion
                                                                at the 139th meeting
        “White Paper” (1/2)                            of the CERN Council (19 October 2006)


           Section 3: Further activities to be funded by additional resources
                                                                              Material      Personnel
        Total request: 240 MCHF during 2008-2010                              (MCHF)       (man.years)
                Theme 1: consolidation and basic improvements:                  103              246
                       Basic consolidation of existing accelerators
                       New power supply for the PS
                       New multi-turn ejection
                       Etc.
                Theme 2: renovation of the old injector complex:
                                                                                 55               185
                       R & D for a new PS and his injector (SPL)
                       Construction of Linac4
                Theme 3: R & D for LHC upgrade and CLIC:                        58               212
                       R & D on superconducting magnets, RF and cryogenics
                       R & D for LHC detectors
                       Increased support for CLIC


                Theme 4: miscellaneous R & D:
                                                                                 41               145
                       SC RF
                       High power target
                       ELENA, HIE ISOLDE, 3rd phase NA-48…



R. G.                                                      5                  IDS meeting - CERN – 29 March 2007
                                              Submitted for information and discussion
                                                       at the 139th meeting
        “White Paper” (2/2)                   of the CERN Council (19 October 2006)


           Section 4: Prospects over the period 2011-2016

            1)




            2) CLIC …

            3) Infrastructure consolidation

            4)




R. G.                                            6                  IDS meeting - CERN – 29 March 2007
        SCENARIOS FOR THE
          UPGRADE OF THE
          ACCELERATORS




R. G.          7     IDS meeting - CERN – 29 March 2007
        CERN accelerator complex




R. G.              8        IDS meeting - CERN – 29 March 2007
                              Upgrades of the accelerator complex
   As proposed by the PAF working group
                                                                            Proton flux / Beam power

                        50 MeV        Linac2
                                                              Linac4
                        160 MeV


                                       PSB                    SPL’
                        1.4 GeV
                                                              RCPSB
                                                                                     SPL
                        ~ 5 GeV


                                               PS                           SPL: Superconducting Proton
                        26 GeV                                                    Linac (~ 5 GeV)
                                                            PS2 (PS2+)
        Output energy




                        40 – 60 GeV                                         SPL’: RCPSB injector
                                                                                  (0.16 to 0.4-1 GeV)
                                                                            RCPSB: Rapid Cycling PSB
                                                                                  (0.4-1 to ~ 5 GeV)
                                                    SPS                     PS2: High Energy PS
                        450 GeV                                                   (~ 5 to 50 GeV – 0.3 Hz)
                                                              SPS+
                        1 TeV                                               PS2+: Superconducting PS
                                                                                  (~ 5 to 50 GeV – 0.3 Hz)
                                                                            SPS+: Superconducting SPS
                                                                                  (50 to1000 GeV)
                                                    LHC /                   SLHC: “Superluminosity” LHC
                        7 TeV                       SLHC      DLHC                (up to 1035 cm-2s-1)
                                                                            DLHC: “Double energy” LHC
                        ~ 14 TeV                                                  (1 to ~14 TeV)

R. G.                                                9                 IDS meeting - CERN – 29 March 2007
                             Benefits for physics

             STAGE                   1                        3                         4
                                  Linac4                 Linac4                    Linac4
         DESCRIPTION               PSB                    SPL                       SPL
         (new accelerator)          PS                 PS2 or PS2+               PS2 or PS2+
                                   SPS                    SPS                      SPS+
                                      +                       ++                       +++
        Performance of LHC
         injectors (SLHC)    Ultimate beam from         Maximum SPS            Highest performance
                                     PS                  performance               LHC injector

        Higher energy LHC            -                         -                       +++
             b beam                  -                    ++ (g ~100)               ++ (g ~200)
                                                       +++ (~5 GeV prod.        +++ (~5 GeV prod.
            n Factory                -
                                                             beam)                    beam)
                                                       ~400 kW beam at           ~400 kW beam at
               k, m                  -
                                                           50 GeV                    50 GeV
            EURISOL                  -                       +++                       +++



R. G.                                             10                    IDS meeting - CERN – 29 March 2007
         Layout of the new LHC injectors



        SPS


        PS2


                                                 SPL




                                                                 PS
                             Linac4

R. G.                   11            IDS meeting - CERN – 29 March 2007
        Proton driver for a n Factory & EURISOL

                                           Connection
                                           PS2 -> TT70




                                                           SPL
              Accumulator &
               Compressor




R. G.                         12      IDS meeting - CERN – 29 March 2007
        Possible layout of a n Factory


              m
         accelerator




                              Target
                                                 m
                                             storage
                                               ring
                   SPL

                              Based on CERN scheme in 2001
R. G.                    13            IDS meeting - CERN – 29 March 2007
                                               LINAC4


                          Technical Design Report (December 2006)
    CERN-AB-2006-084, http://cdsweb.cern.ch/record/1004186
    L. Arnaudon, P. Baudrenghien, M. Baylac, G. Bellodi, Y. Body, J. Borburgh, P. Bourquin, J. Broere,
    O.Brunner, L. Bruno, C. Carli, F. Caspers, S.; Cousineau, Y. Cuvet, C. De Almeida Martins, T. Dobers,
    T. Fowler, R. Garoby, F. Gerigk, B. Goddard, K. Hanke, M. Hori, M. Jones, K. Kahle, W. Kalbreier, T.
    Kroyer, D. Küchler, A.M Lombardi, L.A López-Hernandez, M. Magistris, M. Martini, S. Maury, E.Page,
    M. Paoluzzi, M. Pasini, U. Raich, C. Rossi, J.P Royer, E. Sargsyan, J. Serrano, R. Scrivens, M. Silari,
    M. Timmins, W.Venturini-Delsolaro, M. Vretenar, R. Wegner, W. Weterings, T. Zickler




R. G.                                                 14                     IDS meeting - CERN – 29 March 2007
                               Linac4 parameters


   Ion species                 H−
                                                           Will re-use 352 MHz LEP
   Output Energy               160      MeV                RF components: klystrons,
   Bunch Frequency             352.2    MHz                waveguides, circulators.
   Max. Rep. Rate              2        Hz
   Beam Pulse Length           400      ms
   Max. Beam Duty Cycle        0.08     %
   Chopper Beam-on Factor 62            %                  2 operating modes: low duty
                                                           for PS Booster (PSB)
   Chopping scheme:
                                                           injection in the first phase,
                      222 transmitted /133 empty buckets   high duty for the SPL in a
   Source current              80       mA                 second phase.
   RFQ output current          70       mA
   Linac current               40       mA                 Structures and klystrons
   N. particles per pulse      1.0      × 1014             dimensioned for 50 Hz
   Transverse emittance        0.4      p mm mrad          Power supplies and
                                                           electronics dimensioned for
                                                           2 Hz.
   Max. rep. rate for accelerating structures   50 Hz



R. G.                                      15              IDS meeting - CERN – 29 March 2007
                                Linac4 topology
        95keV      3MeV                    3MeV          40MeV             90MeV          160MeV


  H-         RFQ        CHOPPER             DTL           CCDTL              SCL

  RF          Radio          Chopper       Drift Tube     Cell-Coupled       Side Coupled
  volume      Frequency                    Linac          Drift Tube         Linac
  source      Quadrupole     352 MHz                      Linac
  (DESY)      (IPHI)         3.6 m         352 MHz        352 MHz            704 MHz
  35 kV       352 MHz        11 EMquad     13.4 m         25.3 m             28 m
  Extrac.     6m             3 rf cavity   3 tanks        24 tanks           20 tanks
  60kV        1 Klystron                   5 klystrons    8 klystrons        4 klystrons
  Postacc.    1 MW                         4 MW           6.5 MW             12 MW
                                           82 PMQuad      24 EMQuads         20 EMQuads

                                           Duty cycle:             4 different structures,
                                           0.1% phase 1 (Linac4)   (RFQ, DTL, CCDTL, SCL)
             Total Linac4:                 3-4% phase 2 (SPL)      2 frequencies
             80 m,                         (design: 15%)
             18 klystrons
                                                                   current: 40 mA (avg. in
                                                                   pulse), 65 mA (bunch)

R. G.                                             16               IDS meeting - CERN – 29 March 2007
        The 3 MeV Test Stand

                       In construction, first beam
                       foreseen in 2008.

                       - H- source (DESY type,
                       - LEBT (2 solenoid)
                       - IPHI RFQ
                       - Chopper line (from CERN)
                       - Diagnostics line (IPHI and
                       CERN components)
                       - Infrastructure (1 LEP Klystron,
                       pulsed power supply, etc.)

                       Beam quality is generated in
                       the front-end.
                       => Its early understanding and
                       optimisation is fundamental for
                       a modern linac project.




R. G.          17        IDS meeting - CERN – 29 March 2007
        The IPHI RFQ




                 The 3 MeV Test Stand, Linac4 and finally
                 SPL will use an RFQ built with IPHI
                 technology (brazing at CERN).

                 The RFQ is expected at CERN before the
                 end of 2008.



R. G.       18                   IDS meeting - CERN – 29 March 2007
                        The 3 MeV chopper line

                                                          Compact design 3.7 m length
                                                          Dynamic range 20 – 60 mA
                                                          Small e growth 4% long.,
                                                                            8% trans.
                                                          Tolerant to alignment errors



                                Dumping of chopped
                                beam and collimation of
                                unchopped beam in a
                                conical dump structure



                                                           Chopper structure: double
                                                           meander strip line, 400mm
                                                           length, metallized ceramic
                                                           plate. 2 ns rise/fall time for
                                                           bunch selectivity (352 MHz
                                                           beam structure), ±500V
                                                           between deflecting plates.
        3 RF bunchers
R. G.                           19                   IDS meeting - CERN – 29 March 2007
                             Cell Coupled DTL

                                               Used above 40 MeV:
                                               focusing periods can be longer  structure
                                                   with external quadrupoles, placed
                                                   between short DTL-like tanks
                                               With respect to DTL: can use electro-
                                                   magnets, easy access and cooling,
                                                   easier machining and alignment,
                                                   simpler and more economic
                                                   construction
                                               Modules of 3 tanks connected by coupling
                                                   cells, 2 drift tubes per tank




    High-power prototype tested at CERN


R. G.                                     20                 IDS meeting - CERN – 29 March 2007
        Beam dynamics, aperture and beam size


        Large apertures (>5 times
        rms beam size) to minimise
        losses.
        Scraping foreseen to
        reduce maximum beam
        size in presence of errors.




R. G.                                 21   IDS meeting - CERN – 29 March 2007
                                                   SPL


                             Conceptual Design Report (July 2006)
    CERN-2006-006, http://cdsweb.cern.ch/record/975366
    Baylac, M; (LPSC Grenoble) Gerigk, F (ed.); Benedico-Mora, E; Caspers, F; Chel, S (CEA Saclay) ;
    Deconto, J M (LPSC Grenoble) ; Duperrier, R (CEA Saclay) ; Froidefond, E (LPSC Grenoble) ; Garoby,
    R; Hanke, K; Hill, C; Hori, M (CERN and Tokyo Univ.) ; Inigo-Golfin, J; Kahle, K; Kroyer, T; Küchler, D;
    Lallement, J B; Lindroos, M; Lombardi, A M; López Hernández, A; Magistris, M; Meinschad, T K; Millich,
    Antonio; Noah-Messomo, E; Pagani, C (INFN Milan) ; Palladino, V (INFN Naples) ; Paoluzzi, M; Pasini,
    M; Pierini, P (INFN Milan) ; Rossi, C; Royer, J P; Sanmartí, M; Sargsyan, E; Scrivens, R; Silari, M;
    Steiner, T; Tückmantel, Joachim; Uriot, D (CEA Saclay) ; Vretenar, M;




R. G.                                                22                     IDS meeting - CERN – 29 March 2007
                      SPL New Layout (CDR2, 2006)


                           LINAC4




   New SPL Design (CDR2, CERN Yellow Report 2006-006):
                                                                           Medium     High
   Linac4 (extended to 180 MeV) + 2 superconducting                            b         b
   sections based on 5-cell elliptical cavities at 704 MHz    Cavity b       0.65       1
   (INFN/CEA).
                                                             R/Q (Ohm)        235      575
   Long cryomodules (LHC/TESLA-like, 12-14m), 6-8             Aperture
   cav./module, cold quads in cryomodules                       (mm)          85       90
   Overall length 430m (for 3.5 GeV, was 690m in previous      Ep/Eacc        2.6      2.4
   version for 2.2 GeV)
                                                             Eacc (MV/m)      19       25

R. G.                                        23              IDS meeting - CERN – 29 March 2007
                                 SPL Beam parameters

                                       CDR2         “slim-SPL” for            “MW-SPL”
                                                     SPS & LHC
        Energy (GeV)                     3.5               4-5                       5
        Beam power (MW)                   4             0.15 – 0.19                4-8
        Rep. frequency (Hz)               50                2                       50
        Protons/pulse (x 1014)           1.4               1.2                       1
        Av. Pulse current                 40                10                      40
        Pulse duration (ms)              0.57              1.9                      0.4
        Bunch frequency (MHz)           352.2             352.2                   352.2
        Physical length (m)              430               ~460                    535

          3 different designs:
          CDR2 (2006) based on 700 MHz high-gradient cavities
          “slim-SPL” for LHC (2007) with low beam power, for the needs of the LHC
          “MW-SPL” at higher energy, for the needs of neutrino production



R. G.                                          24                IDS meeting - CERN – 29 March 2007
        SPL cavities: elliptical, 704 MHz

                          Elliptical cavities at b=0.5 (CEA, INFN) are giving
                          promising results. Stiffened for pulse operation.
                                     Length ~ 0.9m
                                     Designed for 12 MV/m.




             * Feed 4 to 6 cavities per
             klystron: use high power phase
             and amplitude modulators.


R. G.                          25                 IDS meeting - CERN – 29 March 2007
                              SPL Beam Dynamics

  Control of losses, minimization of the emittance growth and halo development.

  1)    zero current phase advance always below 90 degrees, for stability;
  2)    longitudinal to transverse phase advance ratio (with current) between 0.5
        and 0.8 in order to avoid resonances
  3)    smooth variation of the transverse and longitudinal phase advance per
        meter.




        Smooth phase advance variation        Selection of the working point (phase
                                              advances) on the Hofmann’s chart
R. G.                                    26                 IDS meeting - CERN – 29 March 2007
                                    PS2

                 Working group started at end 2006
        Benedikt, M; Fabich, A; Goddard, B; Hancock, S; Jowett, J; Laface, E




R. G.                                  27                    IDS meeting - CERN – 29 March 2007
                            Justifications of PS2

           Assure high reliability and availability of injector chain for
            LHC operation
                PS main magnet coils and laminations
                                                              Replace the PS !
                Rotating machine main power converter

           Increase performance of injector chain for LHC operation
                Higher beam brightness by more favourable energy range
                Shorter filling time by improved cycling schemes

           Improve performance for other physics applications in
            energy range PS to SPS (10 to 450 GeV).

           Prepare long-term (energy) upgrade of complete accelerator
            chain
                Higher PS2 ejection energy to reduce SPS+ energy swing




R. G.                                        28               IDS meeting - CERN – 29 March 2007
                                    PS2 design goals
           Beam brightness for LHC:
               Reach twice brightness of the ultimate 25 ns LHC beam (20% reserve for
                losses): 4.01011 per LHC bunch (inst. 1.71011)
               “Ultimate“ bunches at 12.5 ns, twice ultimate at 25ns, etc.
                     Determines average line density in the machine at injection and therefore the
                      injection energy via incoherent SC tune spread.


           Significantly higher injection energy into SPS (~50 GeV).
               Injection into SPS well above transition energy
               Reduced space charge at SPS injection
               Smaller transverse emittances and reduced losses
               Potential for long-term SPS replacement with higher energy.
                     Ejection energy determines PS2 machine size


           As versatile as existing PS
               Protons, ions, high intensity physics beams, slow extraction, etc.




R. G.                                              29                   IDS meeting - CERN – 29 March 2007
                       Considerations on PS2 size

           Existing PS with 25 GeV top energy:
               Combined function magnets with classical lattice.
               Bending radius of 70 m (~440 m length) (B = 1.25 T at 25 GeV)
               114 m (174 m) of (fully used) straight sections.
               Average radius 100 m and machine circumference 628 m.

           PS2: extraction energy ~50 GeV (NC)
               Separated function (eventually complicated lattice for imag. gt)
                     Assume quads will occupy 30 % of integrated dipole length
               NC: dipole at ~ 1.8 T (i.e. bending radius ~100 m, length ~ 630 m)
               Additional space for quadrupoles: ~200 m
               Larger space requirements for insertions: ~300m


             PS2 will have ~twice PS radius i.e. 200 m and 1250 m length




R. G.                                           30                   IDS meeting - CERN – 29 March 2007
        Considerations on PS2 injection energy

           Incoherent space charge tune spread at injection:
               Existing PS with 1.4 GeV injection energy just capable of
                producing the ultimate LHC beam (DQv ~-0.3)




                   Bb… bunching factor (average / peak density for single bunch)
                   Bb will decrease by factor 2 when putting the same bunch in a
                    machine with twice larger circumference (DQ increases with R)!

           PS2: twice ultimate brightness in a twice larger
            machine
               4 times larger incoherent tune spread at given energy.
               Compensation with ratio bg2 at injection:
                     Minimum injection energy PS2: 3.5 to 4 GeV




R. G.                                         31                   IDS meeting - CERN – 29 March 2007
                  PS2 preliminary parameters


                                                      PS2              PS
   Injection energy kinetic (GeV)                      3.5 – 4.0             1.4
   Extraction energy kinetic (GeV)                          ~ 50           13/25
   Circumference (m)                                    ~ 1346              628
   Maximum intensity LHC (25ns) (p/b)                 4.0 x 1011      1.7 x 1011
   Maximum intensity for fixed target physics (p/p)   1.2 x 1014      3.3 x 1014
   Maximum energy per beam pulse (kJ)                       1000              70
   Max ramp rate (T/s)                                       1.5             2.2
   Repetition time at 50 GeV (s)                            ~ 2.5        1.2/2.4
   Max. effective beam power (kW)
                                                             400              60




R. G.                                      32          IDS meeting - CERN – 29 March 2007
        ROADMAP




R. G.     33      IDS meeting - CERN – 29 March 2007
                                      Linac4 project
           2007
                mid-2007
                      Optimization of the layout on the CERN site
                      Negotiation of detailed work packages with external partners
                      CERN Council decision on the « White paper »
               July  September 2007
                      Finalization of the design (updated design report)
                      Conclusion on allocation of work packages / distribution of « remaining » tasks
                       inside CERN
                      Market survey for Civil Engineering
               September  December 2007
                      Project review
                      Project organization inside CERN
           January 2008: official start of the Linac4 project
               Start of Civil Engineering
               Start of construction of Linac4 equipment
           Mid-2010
               Progressive beam commissioning of Linac4
           Mid-2011
               PSB stop for modification
               PSB beam commissioning
           Beginning 2012: PSB operational for physics with Linac4

R. G.                                                34                   IDS meeting - CERN – 29 March 2007
                           Preparation for the SLHC
            end 2010 for LHC and SPS
                Selection of the most promissing scenarios for the LHC upgrade
                Experience with the LHC and its practical limitations…
                Detailed technical design of the LHC upgrade
                Detailed technical design of the SPS upgrade
                Prototyping of critical components
                Detailed estimates of the necessary resources
                Negotiation with external contributors


            end 2010 for the injectors of SPS
                Optimization of the layout on the CERN site
                Optimization of compatibility with other users (EURISOL, n’s, pbars, heavy ions…)
                Detailed technical design
                Prototyping of critical components
                Detailed Civil Enginering drawings
                Detailed estimates of the necessary resources
                Negotiation with external contributors


         publication of Technical Design Reports with resources estimates


R. G.                                               35                   IDS meeting - CERN – 29 March 2007
 Implementation of the LHC luminosity upgrade

           2011  2015 for LHC and SPS
                Construction of components for the LHC and SPS upgrade
                Progressive modification of the SPS (vacuum chamber treatment, impedance
                 reduction etc.)


           2011  2015 for the injectors of SPS
                Construction of SPL and PS2
                Progressive beam commissioning of SPL
                Beam commissioning of PS2


           2016
                Connection of PS2 to SPS & final modifications of the SPS (injection system etc.)
                Beam commissioning of the SPS
                Beam commissioning of the LHC




R. G.                                                36                   IDS meeting - CERN – 29 March 2007
                   Planning of the new injectors

                                                              3 MeV test
                                                              place ready




         Linac4
                                     CDR 2
        approval
                          SPL & PS2 approval


R. G.                                  37      IDS meeting - CERN – 29 March 2007
        SUMMARY




R. G.     38      IDS meeting - CERN – 29 March 2007
           CERN is soon going to commission the largest and
            most sophisticated particle accelerator ever built.
            Such an installation must be fully exploited.
             It is time to prepare for securing its operation, increasing the
              reliability of all the infrastructure for protons and ions.
             It is time to develop solutions for pushing performance to the
              limit.
             It is a unique opportunity to plan new accelerators that can satisfy
              a new generation of physics experiments.

        Mid-2007 is a first crucial milestone in an overall
         planning that should last for a decade.




R. G.                                       39               IDS meeting - CERN – 29 March 2007

				
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