LCWS05 gao 1

 Parameter Choice for ILC(Very Low Charge Case): 

Parameter Choice for ILC (Very Low Charge Case) J. Gao IHEP -ILC Collaboration IHEP, Beijing, China ILC-Aisa Collaboration Meeting, KEK, March 24, 2005

 Content: 

Content Design philosophy Parameter relations Parameter proposal for ILC from IHEP, China Conclusion

ILC Design Philosophy: 

ILC Design Philosophy Required Colliding energy, luminosity Backgroud noise (low) and beam quality (good) Operational condition (stable) Technical constrains (realisable) Damping ring (small space charge effect, reasonable circumference...) 5) Total AC power (reasonable)

Parameter Relations (1) : 

Parameter Relations (1) Luminosity Disruption parameter Beamstrahlung induced Energy spread F(R>>1)=1.3/R

Parameter Relations (2) : 

Parameter Relations (2) Classical radius of electron Particle population inside a bunch R>>1

Parameter proposal for ILC from IHEP, China (1): 

Parameter proposal for ILC from IHEP, China (1) -Wcm=500GeV - -Beamstrahlung energy spread -Mean number of beamstrahlung photons per Electron -Number of hardronic events per crossing (Low background noise)

Parameter proposal for ILC from IHEP, China (2): 

Parameter proposal for ILC from IHEP, China (2) -Disruption parameter -R=103 (flat beam) - low charge is good for many things (Operational stable, small kink instability)

Parameter proposal for ILC from IHEP, China (3): 

Parameter proposal for ILC from IHEP, China (3) - - - - - - (m·rad) (m·rad)

Parameter proposal for ILC from IHEP, China (4): 

Parameter proposal for ILC from IHEP, China (4) - - - If -* - - *Assuming damping ring’s circumference is 17km.

Parameter proposal for ILC from IHEP, China (5): 

Parameter proposal for ILC from IHEP, China (5) -Damping ring Length Ld=17km -Ed=5GeV, damping time -Bunch length inside the damping ring: -Space charge tune shift (y): Space charge problem is solved by parameter choice!

Slide11: 

  Parameter proposal for ILC from IHEP, China (6) Space charge tune shift Particle survival ratio at the ejection

Parameter proposal for ILC from IHEP, China (7): 

Parameter proposal for ILC from IHEP, China (7) Beam current Beam pulse length 0.8ms Peak power per cavity (Eac=35MV/m) 234kW ( , or over coupling factor 1.72 with ) Fill time 0.536ms Rf pulse length 1.34ms

Parameter proposal for ILC from IHEP, China (8): 

Parameter proposal for ILC from IHEP, China (8) Total AC power is around 100MW

Conclusion: 

Conclusion Compared with Tor Raubenheimer’s parameter lists (5 lists for 500GeV case including low Q case), the ILC parameter proposed by IHEP can be named “Very Low Q” (VLQ). 2. VLQ has low IP background noise, operationally stable, large misalignment tolerance, … 3. The space charge problem in the damping rings can be intrinsically eliminated by this parameter choice. 4. There is no fundamental technical limitations

Thanks: 

Thanks 谢谢