1. FCC-ee Interaction Region design
CERN has recently launched the ambitious project of the Future Circular Collider. The same 100 km tunnel will host a hadron-hadron collider with pp collisions at 100 TeV center-of-mass energy (FCC-hh) and e+e- collisions up to 350 GeV center-of-mass energy (FCC-ee). The two colliders should be built in the same tunnel (as was for LEP and LHC). This challenging design study involves a worldwide collaboration with great accelerator physics experts on all the different fields.
INFN participates to the FCC-ee and FCC-hh study (MoU), in particular:
There is a WG for Machine Detector Interface (MDI) in CSN1 of INFN, within RD_FA.
INFN is part of EuroCirCol, the European design study for some key topics of FCC-hh funded by EU under Horizon 2020 (4 years project, started June 2015)
Goal of the study: CDR ready before the next European strategy, by end 2018.
The design of the Interaction Region for FCC-ee is very challenging and is a fundamental step for the feasibility of the collider.
The work for the PhD thesis will focus on the Interaction Region design within the Machine Detector Interface group, on particular aspects of the design, namely
The activity will be to develop particle tracking studies for the main beam loss effects, relevant for the interaction regions design.
Possibility of Benchmark tools with existing colliders, like the LHC and SuperKEKB.

2. Useful Links FCC page at CERN: https://fcc.web.cern.ch/
INDICO page with all FCC meetings:
FCC-ee:
FCC-ee Optics meetings:
FCC-ee MDI meetings:
FCC-hh:
FCC-hh General Design meetings:
FCC-hh beam delivery system meetings:
FCC-hh MDI meetings:
EuroCirCol:

3. FCC-ee IR baseline Layout
beam
Beam energy
GeV
175
bx* / by*
m /mm
1/2
ex / ey
nm/pm
1.3/2.5
sx / sy
mm/nm
36/71 L* m
2.2
full crossing angle
mrad 30
Beam current mA
6.632
Npart/bunch #
1.7x1011
bunches 81
This layout is the starting point for:
detailed design of masks and shielding
tracking of off-momentum particles
Beamstrahlung, radiative Bhabha simulation
beam pipe geometry and material
luminosity monitor

4. Background Studies in the FCC-ee Interaction Region
Contribution to the particle tracking simulation for evaluation of beam losses, relevant for the interaction regions design.
Particle tracking simulation studies for various effects that induce beam losses in FCC Interaction Region and all over the ring , such as:
Radiative Bhabha (Integration with BBBREM)
Beamstrahlung (Integration with GUINEAPIG)
beam-gas scattering
-> existing software tools / development and upgrade
Also :
MAD-X for the magnetic lattice description
ROOT
GEANT4 for interaction in materials
Investigate luminosity-driven losses and its impact on beam intensity lifetime (for FCC-ee).
Use developed software to design shielding and absorbers, optimizing beam pipe dimensions.
Benchmark tools with existing colliders, like the LHC for the FCC-hh studies and SuperKEKB

5. Synchrotron Radiation from the last bend before the IP
Example:
MDISIM[*]
Zoom on the last 200m
aperture shown as circular
r=20 mm central BP, quads
r=50mm bends
Last bend closer than in LEP2 ( 250 m / 100 m )^2 = 6.25 more solid angle
less space for collimators, part for far bend - SR fans directed towards IP
 From last bend
LEP2
FCCee_t_74_11 Eb
100 GeV
175 GeV
Ecr
72 keV
100 KeV
bunchXfreq
45 kHz
180 kHz
γ’s / crossing
3.E+11
4.E+11
γ’s Σ energy / crossing
7.E6 GeV
1.2E7 GeV
[*] : H.Burkhardt and M. Boscolo, Tools for Flexible Optimisation of IR Designs with Application to FCC, IPAC 2015, tupty031

6. FCC-ee baseline parametersZ WW ZH
ttbar
energy/beam [GeV]
45.6 80
120
175
bunches/beam
30180
91500
5260
780 81
bunch spacing [ns]
7.5
2.5 50
400
4000
bunch population [1011]
1.0
0.33
0.6
0.8
1.7
beam current [mA]
1450
152 30
6.6
Horizontal emittance [nm]
0.2
0.09
0.26
0.61
1.3
Vertical emittance [pm] 1
1.2
luminosity/IP x 1034cm-2s-1
210 90 19
5.1
bx* [m] / by* [mm]
0.5/1
1/2
energy loss/turn [GeV]
0.03
1.67
7.55
SR power /beam [MW]
RF voltage [GV]
0.4
3.0 10
Energy acceptance RF [%]
7.2
4.7
5.5
7.0
6.7
Luminosity lifetime [min] 94
185 67 57