Requirements & Studies for CLIC

Transcription

1 Requirements & Studies for CIC Maim Korostelev, CERN Mini-Workshop on Wiggler Optimization For Emittance Control INFN-NF, Frascati - Februar 5

2 laout of the CIC positron damping ring 9[m] dispersion suppressor arc with bending magnets (8 TME cells) R:= 7[m] C:= 36 m E:=. GeV wigglers FODO section 76 wigglers in the ring length of each wiggler is m

3 damping time strength of magnetic field of bending magnet strength of magnetic field of wiggler length of wigglers section ring circumference the factor Fw represents the relative damping in the wiggler compared to the arcs wiggler influence on emittance without action of IBS

4 o = 3m = 3[nm] =.5m τ τ w o.5 B w[t].5.5 o λ _ w [m] _w.5 B w[t] λ _ w [m]..75 w 3.5 B w[t] λ _ w [m] τ τ _ 3 w.5 B w[t] w [m]

5 (m) D s (m) D (m) (m) arc cell arc cell dispersion suppressor D FODO wiggler cell s (m) D(m)

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7 Intra beam scatterin (Bjorken and Mtingwa formalism in the case of ultrarelativistic beams) Intra-beam scattering is the multiple small angle Coulomb interaction of charged particles within bunched or coasting beams [3]. This effect causes both longitudinall and transversel beam diffusion, that leads to the growth of the momentum spread and one or both transverse beam dimensions. The growth rates are: 3 τ A a a G s b b G s = () () () s ds 3 τ A = a G s b c G s ds + () () τ σ δ δ = + A m a G s b G () () s ds in which ( ) G s d a b c 3 3 () / = λ λ λ λ λ λ, ( ) G s d a b c 3 3 () / = λ λ λ λ λ are the azimuthal dependent scattering integrals and a D m = + + σ δ Φ, b D m = σ δ Φ c D m = + σ δ Φ = + D a a = + +, b b = + a a 6 = + Φ, b b a 6 3 = + Φ = beam forcoasting beam forbunched IBS IBS δ δ σ π σ σ π c Nr c r N a s b 3 3 ~ 8 ~ and Φ= + D D α ~ / r r Z = A is the period length, N b the number of particles per bunch, N the total number of particles, c the velocit of light, relativistic factor, normalized beam energ, the m is for coasting beams and for bunched beams, A atomic mass, Z atomic number.

8 second-order achromat arc cell setupoles S S S3 S S5 S6 S7 S8 S9 S6 S7 S8 S S S3 S S5 S6 S7 S8 S9 S6 S7 S8 - I transformer S S S3 - I transformer > ν =.5833 per ν =.5 cell ν = 7π, ν = 7π per ν = 3π ν = 3π > 6 cells

9 Emittance & bunch length evolution in CIC_DR with wiggler period of cm at wiggler field of.5,.,.5 and. T. Energ is. GeV, betatron coupling. %, bunch population. 9, RF phase is constant. (IBS) [nm] T. T (IBS) [nm] σ s [mm] T. T.5 T. T mc σ s σ E/E [ evm] time [s] time [s]

10 Transverse normalized emittances in CIC_DR with wiggler period of and cm (dash line). Energ is. GeV, wiggler field.78 T 9 < bunch population > rf V V rf.55 MV 3.3 MV (IBS) [nm] V rf Vrf 3.3 MV.55 MV (IBS) [nm] (IBS) [nm] 8 6 (IBS) [nm] betatron coupling [%] betatron coupling [%]

11 ongitudinal lormalized emittance and rms bunch length in CIC_DR with wiggler period of and cm (dash line). Energ is. GeV wiggler field.78 T. 9 < bunch population > 3. 9 V rf V rf.55 MV 3.3 MV σ s [mm].8.6. σ s [mm] mc σ s σ E/E [ evm] mc σ s σ E/E [ evm] betatron coupling [%] betatron coupling [%]

12 Emittance & bunch length evolution in CIC_DR with wiggler period of and cm (dash line). Energ is. GeV, betatron coupling. %, RF volage.6 MV, wiggler field.78 T. red line is bunch population of 3. 9 green line is bunch population of. 9 (IBS) [nm] (IBS) [nm] σ s [mm] mc σ s σ E/E [ evm] time [s] time [s]

13 σ... E/E _. %. %. % σ

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15 C, T wiggler period,mm C Têmm wiggler period,mm..75 C, Têmm. -. C 3, Têmm wiggler period,mm wiggler period,mm. C, Têmm wiggler period,mm

16 B3,kG B, kg B5,kG

17 =3.5, =3.5 B, T B, T Bs, T wiggler period wiggler period wiggler period