proposal-channeling by wanghonghx

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									               International Linear Collider




      Study of beam handling by
      crystal channeling at ATF
                            T.Takahashi
                          Hiroshima Univ.

For collaborators:
         KEK (Urakawa, Tauchi, Sawada)
          Hiroshima (Endo, Iinuma, Takahashi, Strokov)
         ( FNAL (Mokov, Drozhdin, Still))
                    Channeling




                               Particle is trapped by the
                               channeling potential




Very strong field         strong bending force
  Application for beam handling


– beam extraction U70(IHEP) ,TEVATRON




– Beam Collimetor   RHIC, TEVATRON, LHC
         Crystal for Accelerators
• beam extraction at
  – IHEP, CERN




• beam collimation,
  – FNAL, IHEP, CERN
         Crystals at ATF
• Study feasibility for
  –beam collimation ILC
    • Study behavior of e- in the bent
      crystal
    • Benefit to ultra-low emittance
      beam?
  –feasibility as a undulator
    • new source for pol. g?
Mokov




        N.Mokov
                     A simulation of
                 halo distribution at SP2
                                                    A.I. Drozhdin




Horizontal (left) and vertical (right) phase plane of 10sx ×80sy beam (DP/P = 0) in
theILCFF9 BDS spoilers and absorbers.


 x  0.02mr         y  0.0008mr  crit (@ 250GeV )  0.01mr
                     Bending eff. for positiron
     for 250 GeV e+ assuming x’/y’ << crit
                                                             L
                         bend =1mr
                                                    e+
bending efficiency




                                                         ben
                                bend =10mr              d




                         length of crystal L [mm]

Cf: current SP 0.6X cupper  0.04mr for 250GeV
                           Bending eff. for positiron
     for 250 GeV e+ assuming x’/y’ << crit
                                                                              L
                                 bend =0.1mr
                                                                     e+
bending efficiency




                     0.8

                     0.7
                                                                          ben
                                          bend =1mr
                     0.6

                     0.5
                                                                          d
                     0.4

                     0.3

                     0.2

                     0.1


                             2        4        6            8   10
                                 length of crystal L [mm]

Cf: current SP、、 0.6X cupper (8.6mm) 0.04mr for 250GeV
                              What about e-
    e+                                            e-
    trapped in between planes                     helical motion around axes
                                                  0.3
                                                                                                             5


                                                  0.2                                                        0

                                                  0.1




                                                                                                       [Å]
                                                                                                             -5




                                            [Å]
                                                  0.0

                                                                                                         -10




                                            y'




                                                                                                       y'
                                                  -0.1


                                                  -0.2
                                                                                                         -15


                                                  -0.3                                                   -20

                                                         -0.3   -0.2   -0.1    0.0   0.1   0.2   0.3              -20   -15    -10   -5    0   5
                                                                          x'     [Å]                                          x'     [Å]
V




                                           x

    Travels in ~flat bottom of planer potentilal                                                 complex helical motion
                                                                                                 along axes
for e-

         complex behavior in bent crystal



         investigation needed for beam
         handling technique


                               1.2GeV
                               e- at INS ES




          helical motion in straight crystal
                  an undulator?
                Collaborators
• Hiroshima
  – over 10 years of experiences to handle crystals
  – parametric x-ray, positron generation, beam
    bending,,,
• KEK
  – ATF beam experts
  – proton beam handling w/ crytstals for J-PARC
     • beam separation, collimation
• US group (FNAL)
  – beam extraction and collimation at Tevatron
    e- beam distortion at INS-ES

• 1.2 GeV e- w/ angular divergence of ~1r




        Obsevation of beam deflection as well as
        distortion of beam profile

      should be much more clear at ATF as
             x’/y’ << crit~0.2mr
  electron beam bending at
          Hiroshima
150MeV e- ring REFER



           結晶
e- beam deflection w/ 16mm Si
                                    0.4
         ψ                          0.3




                 電子ビームの偏向角(mrad)
                                    0.2
    e-
                                    0.1
                                    0.0
                                   -0.1
                                   -0.2
             ψ
                                   -0.3

    e-                             -0.4
                                          -10   -5  0   5       10
                                             結晶軸と電子ビームの角度(mrad)
    Proton beam separation at 12
              GeV PS
                      EP2 line




Proton Synchrotron




                     32mr bent in 12mm
                                         B = 105T
Schematic drawing of the experiment
    view from above

                    deflection
                                           CsI plate
                    angle
crystal                                    (5x2.5cm)


                                 deflected beam
                                                              ceramic plate
                                                              (10x10cm)

                                                  main beam
                     bent crystal
                                        goniometer



          12GeV
          protons
        Observed deflected beam
  CsI




         defected beam   position of main beam


                          メインビーム
Ndeff  5 10 Nbeam   ch   angle   area Nbeam
                5



                  20 85%
                   Plan at ATF
• What we can do at the ATF extraction line in
  this year may be limitted.
  – limitted scace at the beam dump.
      • 130 cm from the last BM to the beam dump




                                      Same set up used at
                                      KEK-PS/Hiroshima
            possible set up in vacuum




10-8torr                             10-5torr(w/ goniometers,screen)

  •differential pumping:
      •pumping speed > 350l/min, connection w/ ~5mm pipe
           preferable to reduce multiple scatteing

  •use 1mm Be seal between ext. line and setup
                                Plan
• First goal is to demonstrate:
   – e- bending w/ bent crystal (not optimized for 1.3GeV e-)
   – profile distortion as a evidence of helical motion
                                                BLM
      • has to be much more clear than what we did at INS
• discuss possible set up w/ ATF staff
   – hopefully ready to install during summer shutdown
   – we can do many in parasitic run
   – -6 shifts dedicated for the exp.
   – Install/remove setup up in a week once estabblished
• Beam collimation project at Tevatron
   – September-October 2005
   – learn how to setup collimation system in real
     beam condition
Crystal at TEVATRON
               General Plan cont.
• electron beam




   •test for beam deflection/collimation at ATF
                                    ATF2
             INSTALLING NEW CRYSTAL IN TEVATRON

Problems with the current BNL/IHEP crystal: too long, too large bending
  angle, O-shaped, 60% of declared 0.44-mrad bending angle, crystal
  squeezed?
A new custom crystal was prepared and characterized at Protvino and
  Ferrara: 3-mm long, 150 mrad bending angle, strip, chemical etching.
It will replace the current one during the Tevatron long shutdown starting
  February 28. Considering better instrumentation.




   C-AD AP Seminar – BNL, Feb. 3, 2006   Crystal Collimation at Tevatron & LHC - N. Mokhov
             Objective

Establish new/effective way of
 handling high energy beams
             for
         J-PARC, ILC


                    beam


crystal a few mm length
Set up at EP2 beam line at PS
ILC BDS
                           Bending eff. for positiron
     for 250 GeV e+ assuming x’/y’ << crit
                     0.8
                                                                            L
                                  bend =1mr
                                                                  e+
bending efficiency




                     0.7

                     0.6
                                                                        ben
                                         bend =10mr
                     0.5
                                                                        d
                     0.4

                     0.3

                     0.2

                     0.1


                             10         20        30         40    50
                                  length of crystal L [mm]

Cf: current SP 0.6X cupper  0.04mr for 250GeV

								
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