2014_01_17_ishi_dist.key

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みそらごみぶち
7 years ago
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1 FFAG! !!!!!

2 1.FFAG 2.FFAG FFAG 7.

3 FFAG: Fixed Field Alternating Gradient B(r) =B(r 0 ) r r 0 k RF ( 6D-focusing i.e. x, px, y, py, s, ps ) RF gymnastics Bunching, Stacking etc.

4 School,London,June 24-28, accelerating time accelerating time accelerating time High Intensity High Energy High Energy & High Intensity Cyclotron *isochronous Synchrotron *const. closed orbit (varying mag. field) FFAG *varying closed orbit (const. mag. field)

5 Main ring operating point MeV 1.35 Qv MeV Qh

6 FFAG KUCA ADS system schematic diagram ( original ) Main ring Injector ion-beta) Booster H+ Target Ion source 125 kev 1.5 MeV 11 MeV 100 MeV Critical Assembly (KUCA)

7 FFAG KUCA ADS system schematic diagram ( upgraded ) from 2011 Main ring H- charge exchange Ion source LINAC H- 30 kev 11 MeV 100 MeV H+ Target Critical Assembly (KUCA)

8 FFAG KUCA ADS system schematic diagram ( upgraded ) from 2012 Main ring H- charge exchange Ion source LINAC H- 30 kev 11 MeV 150 MeV H+ Target 100 MeV Critical Assembly (KUCA) Irradiation chamber

9 Summary of Machine Time ( FY 2012 ) Total 457 hr Irrad. exp. 274 hr Beam study 106 hr ADS. exp. 77 hr unit May. - Oct. Nov. Dec. Jan. Feb. Mar. Apr. Beam Study hr ADS Exp. hr Irrad. Exp. hr Ext. Energy MeV 100/

10 KURRI FFAG! KUCA ADS 100MeV / 1nA 150MeV / 1nA ( ~10nA max ) BNCT 100MeV / 1nA

11 KUCA ADS Require ultra low intensity ( but quite stable ) beams to avoid piling up of neutron counting. e.g. 5pA - 10pA 1/1000 ordinary intensity

12 Fig. Neutron spectra (W vs. W+Be) Fig. Core configuration of 235 U-loaded cores (100 MeV protons) (Protons: 100 MeV, 0.5 na, 100 ns, 20 Hz) 1-2 Fig. In reaction rates (W, W+Be and Pb-Bi)

13 Beam Line and Chamber for Irradiation Experiments

14 150 MeV

15 100 MeV 240nA-h.!

16 Biological experiment of irradiation to mice

17 Upgrade of control system The control system of FFAG accelerator at KURRI has been upgraded with EPICS under collaboration with the KEK accelerator control group. Some parts of the system are using LabView on Windows XP, but they are going to be replaced by EPICS based program for more reliable and secure system.

18 View of Control Room The FFAG accelerator control room. Only one person can operate whole system. There are two Macs link to Windows and LINUX PCs which command PLCs to control accelerator devices.

19 Beam diagnostics system upgrade

20 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil FFAG main ring H - ion source linac charge exchange foil FFAG-ERIT ring

21 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil CT FFAG main ring H - ion source linac charge exchange foil FFAG-ERIT ring

22 CTs installed in vacuum down stream L= 50mH tau = 1ms up stream L = 20mH tau =.4ms

23 Beta functions calculated from backward tracking in the main ring βx ( m ), βy ( m ),Bz ( T ) foil βy βx "fort.52" using ($1/1000):3 "fort.52" using ($1/1000):5 "fort.53" using ($1/1000):(-$7) Bz injection point matching point path length ( m )

24 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil FFAG main ring H - ion source linac charge exchange foil FFAG-ERIT ring

25 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil H - ion source linac Faraday cup FFAG main ring charge exchange foil FFAG-ERIT ring

26 Faraday cup secondary electron suppresssion B by permanent magnet

27 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil FFAG main ring H - ion source linac charge exchange foil FFAG-ERIT ring

28 H- injection Beam injection to the main ring mm F-mag D-mag D-mag H - H + main magnet 3 2 charge stripping foil H - ion source linac bunch monitor & Faraday cup FFAG main ring charge exchange foil FFAG-ERIT ring

29 H- beam Main magnet leakage field can be used for secondary electron suppressor. Added a Faraday cup for calibration of the bunch monitor and to estimate transparency of the first half cell of the ring.

30 Faraday cup Long tailed decay in bunch monitor signal seems to be back scatter of the secondary electron ( suppression is not perfect ) RC constant R = 1MΩ ( input impedance of the amp) C = 171pF faraday cup signal is read thru 50Ω at 20Hz rep. rate I av = V FC dt Faraday cup bunch monitor

31 Beam injection to the main ring The aperture of the up stream Faraday cup might not be sufficient μa mm F-mag D-mag D-mag H - H + main magnet 0.10 μa 2 charge stripping foil

32 Results from beam studies in this summer

33 Injection Studies in ADSR-FFAG Ring output voltage ( V) Bunch monitor signal is amplified by preamp ( x 200 Zin = 1MΩ). In the Straight section S7, the monitor can detect both H- and H+ beam. t ( us ) Beam signal from the bunch monitor

34 Survival ratio Survival ratio vs turn number From the bunch signal in previous slide, survival ratio for each turn is calculated as Bunch Area of i-th turn Survival ratio = Bunch Area of 0-th turn Turn number

35 Emittance growth due to the multiple scattering by charge stripping foil brand-new foil 20 ug/cm2 after 1.5 years...

38 1 2!! 20Hz Hz )!! 20ug/mm 2 10ug/mm 2 )!!! COD!!!!!!

39 PETAL CORE CAVITY 1. New installation of another rf cavity to obtain higher accelerating voltage. ( 4kV 2 x 4 kv )! 2. Reuse of damaged circular core for wide aperture cavities.! 3. A low-power measurements has been done.! 4. With this new cavity, rep. rate 100 Hz can be accomplished.!

40 Innovation research lab. The KURRI-FFAG accelerator complex has been constructed in the innovation research lab. ; connected to KUCA to deliver the high energy proton beam.

41 PETAL CORE CAVITY 1. New installation of another rf cavity to obtain higher accelerating voltage. ( 4kV 2 x 4 kv )! 2. Reuse of damaged circular core for wide aperture cavities.! 3. A low-power measurements has been done.! 4. With this new cavity, rep. rate 100 Hz can be accomplished.!

42 COD correction by the correction dipoles )*+ measured point 0.08 R cavity i.e. COD source 'cod.xy' u 2:3 'cod.xy' u 2:(-$5/100) measured point R2 'cod.xy' u 2:3 'cod.xy' u 2:(-$5/100) 'cod.xy' u 2:3 'cod.xy' u 2:(-$5/100)

43 100 ~ 200 Hz! 5uA

44 Linac 3.5MeV RFQ 7MeV DTL 11MeV DTL 30MeV linac Neutron target proton beam E = 30 MeV I = 1 ma 5 ma duty 10 % ( max ) 700 MeV FFAG 150 MeV FFAG main ring Neutron target proton beam E = 150 MeV I = 1uA short pulse ( ~ 40ns )

45 beam intensity rep. rate : e.g. 100Hz rf stacking RF stacking at the extraction energy rep. rate : e.g. 10Hz at injection energy at extraction energy extracted beam time Some users desire low spill rate ( 10 Hz ) for the experiments e.g. neutron radiography using TOF which needs to get rid of contamination from the pulse of different timing.! FFAG rings can provide long interval pulse for users, while the machine operation itself is kept at high repetition rate by using rf stacking after acceleration[1].! This scheme reduces space charge effects at injection energy. [1] S.Machida, RFStackingatExtractionMomentum,FFAG Workshop 2003,October 13-17, 2003 at BNL, /Machida2.pdf.

46 Machine parameters used in the simulation Table 1: Machine Parameters used in the Simulations field index k 7.7 kinetic energy T [MeV] momentum p [MeV/c] circumference C [m] momentum compaction factor α rf voltage V rf 8 [MV] rf frequency f rf [MHz] harmonic number h 1

47 RF Scenario Vrf 10 s RF voltage kinetic energy f rev s (deg ) φs 8 6 Vrf ( kv ) T ( MeV ) f rev f rev ( MHz ) kinetic energy time ( ms ) time ( ms ) buket area ( evs ) bucket area bucket area In the real machine operation, we use similar scenarios in which synchronous phase φs and rf voltage are fixed at 30 degree and 4 kv respectively during all the acceleration period. On the other hand, in the scenario used in this simulation study, φs is dropped off linearly from 30 to zero degree when the energy of the beam is between 145 and 150 MeV for soft- landing. The rf voltage is also reduced in this region so that the bucket area is constant in order to make momentum spread small at the end of acceleration time ( ms )

48 1st batch nd batch rf phase p ( Mev/c ) # of particles dp/p (%) 250 Stacking processes are simulated using test particles for each acceleration batch.after first acceleration, full width of momentum spread is about 0.5%, the final momentum spread after 10 stacks is 2.5% of full width p ( Mev/c ) # of particles th batch rf phase dp/p (%) p ( Mev/c ) # of particles th batch rf phase dp/p (%) p ( Mev/c ) # of particles rf phase dp/p (%) w/ soft-landing

49 1st batch p ( Mev/c ) # of particles Without soft-landing the final momentum spread after 10 stacks is 5% of full width i.e. twice as large as with soft-landing rf phase dp/p (%) p ( Mev/c ) 5th batch # of particles rf phase dp/p (%) th batch p ( Mev/c ) # of particles rf phase dp/p (%) w/ soft-landing

50 Perturbation from the rf bucket to the coasting beam kV 30deg 4kV 30deg 8kV 40deg 0.25 dp/p ( % ) f r ev ( MHz ) Check if the acceleration bucket affects the stacked beams coasting around the extraction orbit. Generate zero emittance test beam (100 MeV ) with Δp/p = 0 and uniformly distributed in the rf phase. Check if momentum spread is blowing up, while the accelerating bucket is coming up. There are two steps around 2 MHz and 4 MHz in each case. Step around 4 MHz : direct disturbance of the bucket. Step around 2 MHz : f_drive = 1/2 f_rev(stack) It seems that coasting beam can be affected when the accelerating bucket is passing through the frequency which is half of revolution frequency of the coasting beam.

51 2012 3/4 5uA

52 Thank you for your attention!

XFEL/SPring-8

DEVELOPMENT STATUS OF RF SYSTEM OF INJECTOR SECTION FOR XFEL/SPRING-8 Takao Asaka 1,A), Takahiro Inagaki B), Hiroyasu Ego A), Toshiaki Kobayashi A), Kazuaki Togawa B), Shinsuke Suzuki A), Yuji Otake B),