1. 1st HiLumi LHC / LARP Collaboration Meeting 2011 Nov 17th
WP10 (SHORT TERM) PLANS
Francesco Cerutti
1st HiLumi LHC / LARP Collaboration Meeting Nov 17th

2. WP10 ACTORS team N. Mokhov and his team
MARS-FLUKA intercomparison on a dedicated simplified model of the interaction region
LHC Project Note 411 follow up, including dpa and activation calculation

3. WP10 SCOPE
Secondary particle showers and energy deposition calculations are required to address many aspects
warm (TAS, TAN) and cold absorber mechanical design material irradiation test support
electronics shielding
issue
deliverable
synergies
quench
power distribution
WP2, WP3, WP5
cooling
integral power
material damage
dose distribution, differential particle fluence, DPA
SC link
all above
WP6
radiation to electronics
hadron fluence (SEE), ...
R2E
working conditions of instrumentation
differential particle fluence, energy deposition
WP15, BE/BI
background to experiments
differential particle fluence
WP8
activation
radionuclide inventory, residual dose rates
DGS/RP
Cryogenic BLM workshop,
2011 Oct 18

4. THE FOCUS REGION i. collision debris (~ luminosity)
ii. beam losses on the tertiary collimators (~beam intensity)
iii. beam – residual gas interaction(~ beam intensity and gas density)
first

5. BUILDING THE MODEL [I] native FLUKA geometry
Extensive use of lattice capabilities
Element database
Automatic line building

6. BUILDING THE MODEL [II]
MARS15 geometry of IR5
present triplet

7. JAN-JUN 2012 expected INPUT intended OUTPUT
launch the iteration optics – layout – power load with WP2 and WP3 colleagues towards the definition of the triplet aperture as the first goal, implying a coordinated communication of input/output information
set up of a dedicated framework designed to flexibly integrate the evolution of the relevant parameters
layout i.e. magnet (magnetic/mechanical) length, aperture, strength, interconnect correctors
magnet cross section (in particular coil design), field maps
cold bore & (octagonal) beam screen
crossing angle & divergence i.e. β*
TAS aperture
room for shielding (all along the triplet or in the Q1 only)
... experimental vacuum chamber
120 mm, 140 mm x Nb-Ti, Nb3Sn
peak - in the coils - and integral power assessment (beam screen)
shielding optimization
expected INPUT
quench limits
intended OUTPUT

8. 120 mm, 123 T/m (Nb-Ti) sLHCv2.0 by S. Fartoukh x 2.5 x 2.5 x 2.5 x 3
A. Mereghetti’s talk, 2009 Dec 10 SLHC-IRP1, TDG meeting

9. SIMULATION RELIABILITY
stable collisions in P1 at 7 TeV center-of-mass on 2010 Oct 28
BENCHMARKING VS FIRST LHC EXPERIENCE
[A. Lechner]
quench test induced by the wire scanner (at 25cm/s)
on 2010 Nov 1 on the left of P4 at 3.5TeV
absolute comparisons!
geometry details are critical for the accuracy of the prediction of the BLM responses

10. REMARKS & PERSPECTIVES
N.B. despite the reported remarkable agreement wrt the measured BLM patterns, achieved trough the time consuming implementation of many details, Monte Carlo estimates – especially for point quantities – are affected by systematic uncertainties (due to the machine description and the critical dependence on few collision products emitted inside a tiny solid angle). Therefore reasonable margins should never be forgotten, and relative comparisons between different configurations have to be considered as inherently carrying a stronger reliability than absolute predictions, provided that a consistent simulation framework is constantly used
Detailed investigation of the interaction region up to the Matching Section
Construct the complete models of the TAS-D2 region for the preferred triplet aperture and the two alternative superconducting materials
Re-evaluate the power deposition maps on the basis of new layout/geometry details
Assess the peak dose/dpa in all delicate components (coils of quadrupoles, correctors and separation dipoles, cryostat gaskets...)
Calculate the impact of tertiary collimator (TCT) showers on the basis of the available loss maps
Study of the warm absorbers (TAS and TAN)
Provide detailed maps of power deposition on the TAS and TAN
Assist the needed iterations with the successive thermomechanical analyses
Survey on the Matching Section and the Dispersion Suppressor (DS)
Extend the model up to the end of the DS
Evaluate the power deposition profile all along the line, including the beam-gas interaction contribution
Iterate the above evaluation as a function of the active absorber (TCL) scheme
Evaluation of working conditions for instrumentation and electronics
Characterize the radiation field at the locations of the monitors (e.g. BLMs), supporting a possible optimization of their design/positioning; Calculate the relevant radiation quantities at the electronics locations