N. Walker, K. Yokoya LCWS ’11 Granada September TeV Upgrade Scenario: Straw man parameters

Two tentative parameter sets Document distributed on –ILC-EDMS D* Primary constraints: –P AC ≤300 MW –Baseline 500 GeV machine unchanged upgrade scenario: add more linac Two sets proposed for study –  BS ~5%,L ~2.8×10 34 cm -2 s -1 –  BS ~10%L ~4.7×10 34 cm -2 s LCWS - Granada

From 500 to 1000 GeV 2.2 km 1.3 km 10.8 km 1.1 km BDS Main Linac e+ src bunch comp. <26 km ? (site length <52 km ?) Main Linac = 31.5 MV/m G eff ≈ 22.7 MV/m (fill fact.= 0.72) IP central region <10.8 km ? Snowmass 2005 baseline recommendation for TeV upgrade: G cavity = 36 MV/m ⇒ 9.6 km (VT≥ 40 MV/m) Based on use of low-loss or re- entrant cavity shapes Assume Higher Gradient LCWS - Granada

Construction Scenario(s) BDS Main Linac e+ src IP BC BDS Main Linac e+ src IP BC BDS Main Linac e+ src IP BC BDS Main Linac e+ src IP BC start civil construction 500GeV operations Installation/upgrade shutdown civil construction + installation final installation/connection removal/relocation of BC Removal of turnaround etc. Installation of addition magnets etc. Commissioning / operation at 1TeV LCWS - Granada

Ramifications of upgrade scenario Beam pulse structure constrained by baseline 500 GeV machine –RF pulse length( ms) –Main linac current (≤ 9mA) –Cryogenics, CF etc. Original linac (5-250 GeV) must now transport GeV beam –Implications of quadrupoles, lattice and beam dynamics (emittance) Most cost-effective approach –least invasive schedule LCWS - Granada Assumes no major installation/upgrade of RF power source

Luminosity constrained P AC what are the options? LCWS - Granada

Luminosity Goes down with increasing gradient (longer fill time) Constrain to ≤220MW (linac) little to be gained here (factor <1.5) Constrained by physics? shorter increases stability (integrated lumi) LCWS - Granada

AC Power (RDR Linac) LCWS - Granada Wall Plug P beam = V acc ×I beam ≈ 20 MW P RF ≈ 32 MW

AC Power (RDR Linac) LCWS - Granada Wall Plug RF Power Generation (Modulator, klystron, Waveguide distribution) P beam = V acc ×I beam ≈ 20 MW P RF ≈ 32 MW P AC(RF) ≈ 76 MW  ≈ 44%

AC Power (RDR Linac) LCWS - Granada Wall Plug RF Power Generation (Modulator, klystron, Waveguide distribution) P beam = V acc ×I beam ≈ 20 MW P RF ≈ 32 MW P AC(RF) ≈ 76 MW  ≈ 44% to beam dump 56 MW to remove! +24 MW water (CF)

AC Power (RDR Linac) LCWS - Granada Wall Plug RF Power Generation (Modulator, klystron, Waveguide distribution) P beam = V acc ×I beam ≈ 20 MW P RF ≈ 32 MW P AC(RF) ≈ 76 MW  ≈ 44% to beam dump 56 MW to remove! +24 MW water (CF) Cryogenic Power 33 MW

AC Power (RDR Linac) LCWS - Granada Wall Plug RF Power Generation (Modulator, klystron, Waveguide distribution) P beam = V acc ×I beam ≈ 20 MW P RF ≈ 32 MW P AC(RF) ≈ 76 MW  ≈ 44% to beam dump 56 MW to remove! +24 MW water (CF) Cryogenic Power 33 MW 132 MW

Reducing the Repetition Rate P AC = 215 MW (RDR) Doubling linac: * = 355 MW Reduce rep. rate 5Hz to 4Hz: –2×4/5×P RF 130 MW –(1+4/5)×P CF 41 MW –(1+4/5)×P cry 60 MW Total313 MW LCWS - Granada RDR * 132×250/235 This scenario still assumes 31.5 Does not include: additional overhead for gradient spread (+12% RF power) new damping ring configuration

The (Upgrade) Gradient Question Primary a capital cost issue 45 MV/m ⇒ ~20% potential saving in upgrade linac costs Higher Q 0 beneficial –reduced cryo power ⇒ capital cost and power reduction Higher gradient ⇒ reduced efficiency –assuming same current and beam pulse length Hence influences AC power –and therefore luminosity if AC power is constrained LCWS - Granada

Gradient, Power & Luminosity LCWS - Granada Q0Q0 Luminosity reference: n b = 2625 n b scaled to give 300 MW 4Hz operation assumed chosen for straw man parameters n b = 2280 Note: simple scaling only!

Luminosity Parameters Have already reduced P beam –5 down to 4Hz –Reduced n b by 13% Increase  x →  x to constrain  BS Reduce bunch length  z (and  y →  y ) –assume two-stage compressor –(irrespective of decision for 500GeV baseline) Assume  y = 30 nm at the IP –Aggressive –Beam dynamics issues LCWS - Granada

Published Numbers For study purposes only –both machine and detector Machine parameters will be reviewed this workshop Subject to change! LCWS - Granada

Example: Vertical Emittance LCWS - Granada Original 500 GeV linac Assumed FFDD focusing for higher-energy beam BPM scale (calibration) error in conjunction with earth curvature 30 nm K. Kubo (KEK) Simulations of beam-based alignment Standard assumed alignment errors

Pair Angle Kaoru Yokoya Sep LCWS11 Granada, Spain 19

Out-coming Angle of Pairs Pair particle of energy Same sign of charge with the on-coming beam Horizontal angle is comparable to vertical angle Given by (very crudely) Ignore log factor 20

If bunch length is increased –Hourglass serious –But beamstrahlung loss decreases  can make horizontal beam size smaller  luminosity larger  can make vertical beam size larger e.g., 21

22

Very reliminary 10% 150  m 10% 300  m 23

24 Black: 10% 150  m Red : 10% 300  m

25 Black: 10% 150  m Red : 10% 300  m