Parameter Choice for ILC (Very Low Charge Case)

Transcription

1 Paramtr Choic for ILC (Vr Low Charg Cas) J. GAO Institut of High Enrg Phsics Chins Acadm of Scincs Snowmass ILC Workshop, August 14-7, 005

2 Contnt Dsign philosoph Paramtr rlations Paramtr proposal for ILC from IHEP, China Conclusion

3 ILC Dsign Philosoph Rquird Colliding nrg, luminosit Backgroud nois (low) and bam qualit (good) Oprational condition (stabl) Tchnical constrains (ralisabl) Damping ring (small spac charg ffct, rasonabl circumfrnc...) Total AC powr (rasonabl)

4 Luminosit L Paramtr Rlations (1) f rp b 4π x H D Disruption paramtr D x, r z γ ( + ) x, x Bamstrahlung inducd nrg sprad δ B r 3 γ 3 x z F ( R ) F ( R 1) 1.3 / R R x

5 n γ Paramtr Rlations () α r 1 H n γ γγ γγ x x Had D Had 4π x Had R 1 (pr incidnt particl) m 35 (pr crossing) r Classical radius of lctron Particl population insid a bunch

6 had frpb n γ Paramtr proposal for ILC from IHEP, China (1) L had f rp b n γ γ γ H a d Wcm500GV Luminosit L 1 0 c m i s Bamstrahlung nrg sprad 34 1 δ B Man numbr of bamstrahlung photons pr Elctron n γ 0.8 umbr of hardronic vnts pr crossing 0.15 Had (Low background nois) 0.03

7 Paramtr proposal for ILC from IHEP, China () Disruption paramtr D 9 H 1.5 (Oprationall stabl, small kink instabilit) R103 (flat bam) Vr Low Charg (VLC) is good for man things D

8 x 16πα r Had 4 HDn γ γγ Had Paramtr proposal for ILC from IHEP, China (3) - 3 π r H had x.6δ α H n γ γγ B D Had 7 x m - 3 r n γ 41.5δ B α m - z 4.6 r n γ δ B γ α 4 z m -R x 16πα r Had 4 H D nγ γγ R 103 Had

9 - β x Paramtr proposal for ILC from IHEP, China (4) 3 3.5πγ r Had δ H B D γγ Had n γ β x 0.01 m β - z / β m - γε x π r 3 Had BH D γγ Had 3.4δ α ε nx m rad 6, * γ - 8 γε 374δ n B r α 4 ε n,.7 10 m* rad

10 - Paramtr proposal for ILC from IHEP, China (5) π r Had B H D γγ H ad δ α - x n γ α r f - rp b Lnγ γγ Had f rp b Had P- b π W cm r nγ L P 10.4H δ α 10.3 b MW D B

11 Paramtr proposal for ILC from IHEP, China (6) f 8 H 5376 If thn rp z b T - bunch spration ring 10.5 ns - * T I bunch spration linac bam 150ns 6.45mA T 0.8 bam m s *Assuming damping ring s circumfrnc is 17km.

12 Paramtr proposal for ILC from IHEP, China (7) Bam currnt Bam puls lngth 0.8ms Pak powr pr cavit (Eac35MV/m) is 34kW 6 9 Q xt ( Q , or ovr coupling factor with Q ) Fill tim 0.536ms 6.45mA Rf puls lngth 1.34ms I b Total AC powr is around 100MW

13 Paramtr proposal for ILC from IHEP, China (8) Rlation btwn th damping ring charactristic paramtrs and th bam paramtrs at IP: γ 3 d zd 33 δ Bα γγ π ξ sc, nγ r L d L d D Had Had Whr is th damping ring circumfrnc, zd is th bunch lngth aftr bunch Lngthning, γ d is th normalizd damping ring s nrg, and ξ sc, is th tolrabl spac charg tun shift. H

14 Paramtr proposal for ILC from IHEP, China (9) If TESLA tp damping ring is adoptd Damping ring Lngth Ld17km 9 Ed5GV, 6 10 damping tim τ 8ms Bunch lngth insid th damping ring: z, d 8 m m aftr bunch lngthning Spac charg tun shift (): ξ r d 3/ n, x n, 1/ d z, d sc, ( π ) ( ε ε ) β γ ξ sc, L

15 Paramtr choic for damping ring (10) Damping ring Lngth Ld17km 9 Ed5GV, 6 10 damping tim Spac charg tun shift (): ξ Stord tim: τ st 00ms Particl s liftim du to nonlinar spac charg forcs: Th rlativ particl s survival population r d 3/ n, x n, 1/ d z, d sc, ( π ) ( ε ε ) β γ τ sc, sc, L τ 8ms 1 τ 3 3 ( ξ ) xp πξ πξ sc, sc, R ( ξ sc, ) xp τ τ st ( ξ ) sc, sc,

16 Spac charg tun shift Paramtr proposal for ILC from IHEP, China (11) Particl survival ratio at th jction

17 Paramtrs (slctd) for 500 GV Ecm ominal Low Q Larg Y Low P Vr low Q (IHEP) /bunch E10 1E10 E10 E10 6E9 b/puls Tsp(ns) I_b (ma) γε (E-8m) β*x (mm) β* (mm) x (nm) (nm) z (mm) D δb ξ s c at 5 GV,

18 On damping ring nrg and bunch lngth choic If w tak damping ring nrg bing 7GV, L17km, and bunch lngth aftr bunch lngthning ffct 6mm, and ξ, 0.05 sc th following quation will b satisfid b almost all Tor s paramtr lists γ 3 d zd 33 δ Bα γγ π ξ sc, nγ r L d z H D H a d H a d

19 Conclusions 1) Aftr compard Vr Low Q (VLQ) cas with Tor Raubnhimr s low Q cas paramtr, w hav a clar prfrnc among diffrnt paramtr lists, Vr Low Q or Low Q. ) If 17km damping ring is to b adoptd, th damping ring s nrg should b 7 GV instad of 5 GV. If short ring is adoptd(sa 6km), damping ring s nrg can b adjust accordingl (sa 5GV). 3) Th spac charg problm in th damping rings should b intrinsicall liminatd b paramtr choic instad of through coupling tchniqu.