Permanent Magnet Quadrupole Lens with Variable Strength

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					                                                                         ICFA Nanobeam02
• Title


          Permanent Magnet Quadrupole Lens
                with Variable Strength
                         Yoshihisa Iwashita
            Accelerator Laboratory, Nuclear Science Research Facility,
               Institute for Chemical Research, Kyoto University,
                       Gokanosho, Uji, Kyoto 611, JAPAN
                       iwashita@kyticr.kuicr.kyoto-u.ac.jp
                        http://wwwal.kuicr.kyoto-u.ac.jp

           Contents:
           • Introduction - Superstrong PMD
           • PMQ, iPMQ (saturated iron PMQ)
           • Variable
           • XPMQ
           • Sketch
           • NanoControl

                                                                                  AccLab NSRF ICR
                                                                                   KyotoUniversity
• PMD & B-H curve


       Halbach's dipole REC magnet.      B [T]
                                          3.0            B [T] Soft iron
                                                         B [T] NEOMAX35
                                          2.5


                                          2.0


                                          1.5


                                          1.0


 Beam axis                                0.5


                                          0.0
                                           -200   -100   0     100   200   300   400

             1.37 T @r1, r2=1cm, 4cm                         H [k A/m]




                     B=Br ln(r1/r2) cos( /M) sin( /M)/
                                                                                       AccLab NSRF ICR
                                                                                        KyotoUniversity
• SuperPMD
                              Modified Halbach's magnet.




                         Fe

 1.64 T @r1, r2=1cm, 4cm
 (was 1.37T)      Beam axis




                                                           AccLab NSRF ICR
                                                            KyotoUniversity
• 4.45T Dipole




          Achieved 4.45T @-29 C (3.9T @room temperature)
    M. Kumada et al., CERN Courier, vol. 41, no.7,Sep. 2001, p. 9
                                                                    AccLab NSRF ICR
                                                                     KyotoUniversity
• PMQ & iPMQ – Gradient (Field plot)


                                                      2.5
                                                                                 with Fe 2.4 [T/cm]
                                          ID: ø20     2.0
                                          OD: ø240
                                                                 with Permendur
                                                                    2.5 [T/cm]
                                                      1.5




                                                     By
                                                                                   PM only
                                                      1.0                         2.2 [T/cm]



                Fe                                    0.5
                                                                            By (iPMQ1 w/Permendur)
                                                                            By (iPMQ w/Fe) [T]
                                                                            By (PMQ16) [T]
                                                      0.0
     iPMQ16 16seg ID=6 OD=24

     0 10
                               CY CLE =   7
                                                            0   0.2   0.4        0.6      0.8        1
                                              120                            X

     B=2Br (1-r1/r2) cos2( /M) sin(2 /M) /(2 /M)


                                                                                                     AccLab NSRF ICR
                                                                                                      KyotoUniversity
• IP




       Superconducting Q   Room temp. Q
                                          AccLab NSRF ICR
                                           KyotoUniversity
• Final Focus PMQ



                                                      8 m rad
                                          leaving beam

  IP
         ø10        ø32        ø40        ø48        ø56     incoming

  0m
               2m Module1 Module2    Module3    Module4 4m




       need some mergine for leaving beam


                                                                   AccLab NSRF ICR
                                                                    KyotoUniversity
• Let the beam go through

                                 nPMQ                                           xPMQ2                  sPMQ


                                                                                                        sPMQ1 6 16se g ID= 0 .5 OD = 1.3    E =   6   sPMQ1 6 16se g ID= 0 .5 OD = 1.3        LE =      6




                                                                                                      By [T]
                                                                                                      2.0
                                                                                                                                    By [T] ixPMQ
                                                                                                                                    By [T] nPMQ
                                                    iPMQ16 16se   0 .5 OD = 4.0    CY CLE =       6
  iPMQ16 16seg   0 .5 OD = 4.0    CY CLE = 7
                                                                                                      1.5                           By [T] xPMQ2
                                                                                                                                    By [T] xPMQ1
                               xPMQ1                                            ixPMQ                                               By [T] sPMQ
                                                                                                      1.0



                                                                                                      0.5



                                                                                                      0.0
 iPMQ16 16seg    .5 OD = 4.0     CY CLE =      7   iPMQ16 16seg   .5 OD = 4.0     CY CLE =    7          0                                 0.1          0.2                  0.3             0.4
                                                                                                                                                       X [cm]
                                 Beam pipe for leaving beam?
                                                                                                                                                                                         AccLab NSRF ICR
                                                                                                                                                                                          KyotoUniversity
• Final Focus vPMQ
                         F F F F F • • • • •
                                                                8 m rad
                         F D F D F • • • • •
                                                    leaving beam
                   ø32
   IP
             ø10                        ø40         ø48        ø56     incoming

   0m
                     2m Module1 Module2        Module3    Module4 4m


    5~10cm/unit —> 20~40units/2m                      Stepwise variable
       ... some units may be fixed                  Higher resolution by
                                                    binary increment of
                                                    the length: 1,2,4,... cm
   strongest   F F F F F F F F F F • • • • •
    • • •
   middle1
   middle2
               F F F D F D F D F D • • • • •
               F D F D F D F D F F F • • • • •   } centroid move
    • • •
   weakest     F D F D F D F D F D • • • • •


                                                                           AccLab NSRF ICR
                                                                            KyotoUniversity
• X-Y stage supplied by NanoControl Co.Ltd.




                                                Piezo Actuator
                                               stroke:15µm/2cm

                           Supersonic Motor or Pneumatic system




                                                            AccLab NSRF ICR
                                                             KyotoUniversity
• Some issues

        Strength        10-5 ?
        Displacement    0.2 nm ?
        Rotation (skew) 3µ rad ?
       above three needs temperature compensation
        Step size?
        Multipole component?
                          (dodecapole)
        Radiation damage?
        temperature coefficient?
        Helical Quadrupole(round beam)?

                                                    AccLab NSRF ICR
                                                     KyotoUniversity
• Temperature Coefficient Compensation


       Basic idea from E.Antokin
            NdFeB:
            SmCo:
                       -0.11%/ C
                       -0.03~0.04%/ C    }   x4 difference




                F       D            F
             SmCo NdFeB SmCo                         heat source
                 2 :     1   :   2                   along the axis



                                                                  AccLab NSRF ICR
                                                                   KyotoUniversity
• Quad center monitor


                        r=5mm beam pipe

                                    Many Hall probes




                              Accuracy of 10-4 may locate the
                              magnetic center with
                              5 mm x 10-4 =0.5 µm or better
                              including multipoles.

             Radiation damage?
             Dirfts?

                                                                AccLab NSRF ICR
                                                                 KyotoUniversity