Brain Gestorme: Status of the Brain Gestorme: Status of the LHeC Ring-Ring / Linac-LHeC Ring-Ring / Linac-

Ring Basic ParametersRing Basic Parameters

I appologise to talk about things you already know ...

Design Parameterselectron beam RR LR ERL LRe- energy at IP[GeV] 60 60 140luminosity [1032 cm-2s-1] 17 10 0.44polarization [%] 40 90 90bunch population [109] 26 2.0 1.6e- bunch length [mm] 10 0.3 0.3bunch interval [ns] 25 50 50transv. emit. x,y [mm] 0.58, 0.29 0.05 0.1

rms IP beam size x,y [m] 30, 16 7 7

e- IP beta funct. *x,y [m] 0.18, 0.10 0.12 0.14

full crossing angle [mrad] 0.93 0 0geometric reduction Hhg 0.77 0.91 0.94

repetition rate [Hz] N/A N/A 10beam pulse length [ms] N/A N/A 5ER efficiency N/A 94% N/Aaverage current [mA] 131 6.6 5.4tot. wall plug power[MW] 100 100 100

proton beam RR LRbunch pop. [1011] 1.7 1.7tr.emit.x,y [m] 3.75 3.75

spot size x,y [m] 30, 16 7

*x,y [m] 1.8,0.5 0.1$

bunch spacing [ns] 25 25

$ smaller LR p-* value than for nominal LHC (0.55 m):

- reduced l* (23 → 10 m)- only one p beam squeezed- IR quads as for HL-LHC

RR= Ring – RingLR =Linac –RingERL=energy recovery linac

Tentative: 8.7.2010

Change in Electron Energy: 70 GeV 60 GeVBeam Emittance

again requiring:

What do we gain in this case ?relaxed separation scheme (dominated by e-emittance)smaller crossing angle !!!

keeping cool … i.e. keep σe constrelax the electron optics

the crossing angle: in the end the source of many problems

First parasitic crossing: s = 3.75m

F. Willeke

βx

€

ex = 5.0 nm

εey = 2.5 nm

Separation: 5σp + 5σe =0.35mm+ 5mm ≈5.5 mm

X-angle ≈ 1.4 mrad

the crossing angle: in the end the source of many problems

First parasitic crossing: s = 3.75m

F. Willeke

βx

Separation:

Luminosity Loss Factor:

sc half quadrupole: g = 127 T/mfield free region (e-beam) ≈ Gaussseparation required ≈ 50 mm

Beam Separation at first p – Quadrupole: ... a technical problem

S. Russenschuck

sc quadrupole Q2: field free region (e-beam) ≈ Gaussseparation required ≈ 85 mm

Beam Separation at second p – Quadrupole:

S. Russenschuck

complete the electron ring latticeinclude the IR into Miriams Arc / Dispersion suppressor geometry

match the electron ring optics from β* to the periodic solution for 1 & 10 degree option

determine βmax at first parasitic encounterre-iterate the separation scheme-> recalculate the synchrotron light-> input for Nathan: Absorber Geometry

write report

Further Plans:

status e-optics for IPAC 2010

Design Parameterselectron beam RR LR ERL LRe- energy at IP[GeV] 60 60 140luminosity [1032 cm-2s-1] 17 10 0.44polarization [%] 40 90 90bunch population [109] 26 2.0 1.6e- bunch length [mm] 10 0.3 0.3bunch interval [ns] 25 50 50transv. emit. x,y [mm] 0.58, 0.29 0.05 0.1

rms IP beam size x,y [m] 30, 16 7 7

e- IP beta funct. *x,y [m] 0.18, 0.10 0.12 0.14

full crossing angle [mrad] 0.93 0 0geometric reduction Hhg 0.77 0.91 0.94

repetition rate [Hz] N/A N/A 10beam pulse length [ms] N/A N/A 5ER efficiency N/A 94% N/Aaverage current [mA] 131 6.6 5.4tot. wall plug power[MW] 100 100 100

proton beam RR LRbunch pop. [1011] 1.7 1.7tr.emit.x,y [m] 3.75 3.75

spot size x,y [m] 30, 16 7

*x,y [m] 1.8,0.5 0.1$

bunch spacing [ns] 25 25

$ smaller LR p-* value than for nominal LHC (0.55 m):

- reduced l* (23 → 10 m)- only one p beam squeezed- IR quads as for HL-LHC

RR= Ring – RingLR =Linac –RingERL=energy recovery linac

Tentative: 8.7.2010

IR principles for a LR Design (R.T.) The proton IP beta function is pushed down to 10

cm and head-on collisions are achieved via an IR dipole.In order to keep the proton triplet chromaticity to an acceptable level the l* (distance from IP to first quadrupole) has to be reduced from 23m (LHC nominal) to 10m.It is proposed to create a separating dipole field already very close to the IP, being embedded in the Solenoid design of the particle detector.

βp=10 cml*= 10 m

“It was proposed to do a new "toy" design to get to the level of 200 keV and compare the results.”