2. LHC/HL-LHC and Injectors - status and prospects
G. Arduini, Accelerators and Beam Physics Group, Beams Department
CERN
Acknowledgements: A. Apollonio, F. Bordry, M. Calviani, S. Danzeca, P. Fessia, M. Hostettler, G. Iadarola, R. Jacobsson, M. Lamont, A. Lechner, M. Pojer, S. Redaelli, L. Rossi, G. Rumolo, W. Scandale
21/09/2016
G. Arduini - INFN CSN1

3. 2016: a production year LHC schedule 2016
Integrated luminosity goal:
2016 :  25 fb-1 at 13 TeV c.m
Chamonix’16 conclusions (January 2016)
21/09/2016
G. Arduini - INFN CSN1

4. Summary: 2015-2016: Peak Performance
Parameter
2015
2016
Nominal
Energy [TeV]
6.5
7.0
Nb [1011 p/bunch]
1.2
1.15
k (no. bunches)
2244
2220
2808
Bunch spacing [ns] 25
Stored energy [MJ]
280
362
e* [mm]
3.5
3.5  2.0
3.75
b* [m]
0.8
0.4
0.55
Full crossing angle [mrad]
290
370280
285
L [1034 cm-2s-1]
0.5
1.0
Average beg. of fill 28 40 26
The choice of challenging accelerator parameters has paid off!!
21/09/2016
G. Arduini - INFN CSN1

5. Statistics: 2015 vs 2016
Longer fills (average length doubled wrt 2012 and 2015)
Faults mainly grouped in few long interruptions (weasel, PS power supply, SPS beam dump, etc.)
2015
Stable beam fraction in 2012 was 36%
Encouraging for HL-LHC!
2016
21/09/2016
G. Arduini - INFN CSN1

6. Statistics: 2015 vs 2016
Replacement of non radiation hard components in QPS boards during TS in September 2015
2015
2016
Significant work done by Cryogenics to automatize controls in the presence of large heat loads during YETS
21/09/2016
G. Arduini - INFN CSN1

7. Integrated luminosities
Chart with delivered ATLAS lumi, compared per year
Integrated luminosities
21/09/2016
G. Arduini - INFN CSN1

8. Radiation to Electronics
A lot of work done (mitigation measures are balanced by increased cumulated dose…)
Further measures are planned for HL-LHC
Remove all sensitive equipment from tunnel
PC powering through SC (HTS) links
QPS systems delocalized
Develop rad-hard electronics
Only 3 radiation induced dumps till now!
Lower than foreseen radiation level (might be due to reduced beam-gas)
Equipment
Dumps 2012
Dumps 2015 (After TS2)
QPS 32 3
Power Converter 15 7
Cryo 4
EN/EL 1
Vacuum
Collimation RF 4*
Others (hidden) -
Total
3 /fb-1
~3.4 /fb-1*
2.3 /fb-1
Predicted Dumps 2016 (35fb-1)
0-5
~25 ?
0-10
~1-1.5 /fb-1
Predicted Dumps 2017 (45fb-1)
0-5
0-10 ?
~0.5 /fb-1
QPS strategy
EPC strategy
* To be confirmed
21/09/2016
G. Arduini - INFN CSN1

9. UFOs in 2016 Further conditioning has been observed this year
11 BLM dumps (w/o quench), 3 quenches in 2016
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G. Arduini - INFN CSN1

10. Slow conditioning - Need longer trains next year (TIDVG repair)!
Electron Cloud
Slow conditioning - Need longer trains next year (TIDVG repair)!
21/09/2016
G. Arduini - INFN CSN1

11. …still 29 days of pp physics ahead!!
LHC 2016 schedule
…still 29 days of pp physics ahead!!
21/09/2016
G. Arduini - INFN CSN1

12. LHC: new schedule approved on 31st August
Initial LHC SCHEDULE
LHC Proton Run 2016 is reduced by one week: one week investment for energy increase
The restart date in 2017 is unchanged
New Schedule
Training of 2 sectors towards 7 TeV (max 2 weeks)
21/09/2016
G. Arduini - INFN CSN1

13. Possible 2017/18 parameters Nominal BCMS Beta* (1/2/5/8) 0.4/10/0.4/3
Half crossing angle
-185/120/185/-150
-155/200/155/-150 Nc
2736
2448
Proton per bunch
1.25e11
Emittance into SB
3.2
2.3
Bunch length
1.05
Peak luminosity
1.4e34
1.7e34 *
Peak pile-up 37 51
Luminosity lifetime 20 15
* limited to ~1.7e34 by inner triplets (Laurent Tavian Evian 2012)
21/09/2016
G. Arduini - INFN CSN1

14. Run 2 Ion runs in 2016 (p-Pb) and 2018 (Pb-Pb)
Extended Year End Technical Stop – 20 weeks
General maintenance: LHC and injectors CMS pixel upgrade;
Push 2 sectors towards 7 TeV
Peak luminosity to ~1.7e34 (limited by inner triplets)
~ fb-1/year in 2017 and 2018 (goals will be fixed at Chamonix 2017)
Prepare for HL-LHC and post-LS2 LIU era
Prepare for 7 TeV operation
21/09/2016
G. Arduini - INFN CSN1

15. HL-LHC Timeline & Goals
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G. Arduini - INFN CSN1

16. Recent Project Milestones
Completion of the European Funded Study (October 2015)
Publication of a Preliminary Technical Design Report (November 2015)
Internal Review of the of the Civil Engineering and Technical Infrastructure costs (May 2016)
Internal Review of the HL-LHC configuration/parameters (June 2016)
Approval of the HL-LHC Project by the CERN Council (June 2016) for a total accelerator material cost of 950 MCHF
21/09/2016
G. Arduini - INFN CSN1

17. Work done to minimize the required volume
Civil engineering
Extra cost of ~120 MCHF for civil engineering and technical infrastructure w.r.t. the initial estimates
Work done to minimize the required volume
21/09/2016
G. Arduini - INFN CSN1

18. The HL-LHC IR (new baseline)
Reduction of the triplet gradient from 140 T/m to 133 T/m. Additional safety margin taking into account of the completely new technology
Staged installation of larger aperture quadrupole for other optics configurations (flat) following June review
IP1&5
HL-LHC
Reduction #Crab Cavities from 4 to 2/beam/IP side (3 required for full compensation) - reversible
LHC
IP1&5
21/09/2016
G. Arduini - INFN CSN1

19. Dispersion Suppressor Collimators with 11 T Dipoles
New collimators (TCLD) with 11 T dipoles around the LSS7 only. 2 units sufficient (initially 4) according to recent simulation results and MDs. Reversible.
LHC MB replaced by 3 cryostats + collimator, all independently supported and aligned:
Same mm length between interconnect planes as an LHC MB
Connection cryostat between two 11 T magnets to integrate the collimator
Same interfaces at the extremities: no changes to nearby magnets, standard interconnection procedures & tooling
D. Duarte
21/09/2016
G. Arduini - INFN CSN1

20. HL-LHC Parameters Parameter Nominal HL-LHC updated
Bunch population Nb [1011]
1.15
2.2
Number of bunches
2808
2748
Beam current [A]
0.58
1.12
Stored Beam Energy [MJ]
362
677
Full crossing angle [mrad]
285
590
512
Beam separation [s]
9.4
12.5
Min b* [m]
0.55
0.15
0.2
Normalized emittance en [mm]
3.75
2.5
r.m.s. bunch length [m]
0.075
0.081
Peak Luminosity (w/o CC) [1034 cm-2s-1]
1.2 (1.2)
21.3 (7.2)
12.6 (6.5)
Max. Luminosity [1034 cm-2s-1] 1
5.3
Levelled Pile-up|Pile-up density [evt. | evt./mm]
26/0.2
140/1.2
140/1.3
The virtual luminosity refers to the case with half crab cavities
21/09/2016
G. Arduini - INFN CSN1

21. Nominal scenario , 240 fb-1/y for 160 days ions collisions end at LS4 Physics days: 160 Run4  200 Run5 220 Run6
HiLumi LHC
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
21/09/2016
G. Arduini - INFN CSN1

22. Ultimate scenario : 320 fb-1/y for 160 days ions collisions end at LS4 Physics days: 160 Run4  200 Run5 220 Run6
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
HiLumi LHC
Ultimate scenario assume 8% higher efficiency than nominal
Last run with 220 days and 8% higher efficiency: 440 fb-1/y
21/09/2016
G. Arduini - INFN CSN1

23. “Physics Beyond Colliders” Study Group established in March 2016
Mandate
Explore opportunities offered by the (very rich) CERN accelerator complex to address
outstanding questions in particle physics through projects:
complementary to high-energy colliders (studied at CERN: HE-LHC, CLIC, FCC)
 we know there is new physics, we don’t know where it is  we need to be as broad
as possible in our exploratory approach
exploiting the unique capabilities of CERN accelerator complex and infrastructure and
complementary to other efforts in the world:
 optimise the resources of the discipline globally
Enrich and diversify CERN’s future scientific programme
F. Gianotti
Kick-off meeting 06/09/2016
Goal is to involve interested worldwide community, and to create synergies with other
laboratories and institutions in Europe (and beyond).
Note: interesting ideas may emerge from these studies which do not need to be realised at CERN.
Overall coordinators: Joerg Jaeckel (Heidelberg; theory), Mike Lamont (CERN; accelerator),
Claude Vallée (CPPM and DESY; experimental physics)
Kick-off meeting 6-7 September 2016
Final report by end 2018  in time for update of European Strategy
21/09/2016
G. Arduini - INFN CSN1 23

24. New ideas (some of them....)
SPS Beam Dump Facility
complete technical feasibility studies of a beam dump facility in the CERN North Area (extraction, target, radiation protection)
Electric Dipole Moment
Polarized protons, 0.7 GeV storage ring
LHC fixed target via crystal extraction
LHC fixed target via internal gas jet
NuSTORM – explore possible synergies (e.g. target…)
Study reports at a appropriate level depending on the maturity of project proposal with possibly a rough resource/timescale estimate
21/09/2016
G. Arduini - INFN CSN1

25. Objective
For update of the European Strategy for Particle Physics in ~
Evaluation of the physics case in a world wide context
Will range from:
Results of BDF feasibility studies
Exploratory study reports for selected new ideas
Required R&D going forward –initiate feasibility studies depending on resources
Preliminary evaluations of more long term options
Ranking left to ESU
Working groups to be set-up
Will inform the community once the structure has been decided
21/09/2016
G. Arduini - INFN CSN1

26. North Area and Beam Dump Facility
BDF
Prevessin site
TT20
SPS
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27. Requirements
High intensity proton beam: 4*1013 p+/pulse, 4*1019 POT/year, 355 kW average beam power (CNGS ~500 kW)
Slow extraction (~1 sec. flat top)
O(400 GeV) optimal beam momentum
Minimal impact on running the North Area program
Dense target/dump to maximize production & stop p and K before decay into m+n
- Maximize production (cross-section scales with A^0.7 for mesons + extra yield from cascade processes in long target, and Z^2 for photons)
The proposed BDF is a new permanent facility in the NA with unprecedented average beam power
21/09/2016
G. Arduini - INFN CSN1

28. The main challenges for a BDF
Target design for longevity and reliability
Extraction from SPS
High cumulated radiation doses
Injectors, injection, extraction, target, etc…
Radiation damage on materials
Extraction septa, target and target station
Personnel and environmental protection
Close distance to the CERN site boundary
Detailed environmental study needed
Good compatibility with North Area operation
21/09/2016
G. Arduini - INFN CSN1

29. BDF scenario: proton sharing
BDF goal
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G. Arduini - INFN CSN1

30. LIU upgrades and non-LHC physics
LIU upgrades implemented in LS2
Goal is to double intensity and brightness of LHC beams
Benefits for non-LHC physics beams
ISOLDE, HiRadMat, AWAKE
Potential for nTOF and SPS Fixed Target
Still limitations from beam loss and machine activation
21/09/2016
G. Arduini - INFN CSN1

31. Outstanding intensity limitations for non-LHC beams
Beam losses in all accelerators  machine activation
PSB: Losses at recombination septum limit vertical emittance of high intensity beams
PS: Losses at extraction  With currently operational Multi Turn Extraction (MTE) islands are extracted without need of intercepting device and losses are controlled
SPS:
Losses due to limited vertical acceptance
Losses on electrostatic septum (ES) during slow extraction – might pose in the future a serious limit on the maximum number of protons per year that can be extracted to the North Area
Capture losses
Other intensity limitations  Require additional beam dynamics studies
PS & SPS
RF power
Beam instabilities
Heating/outgassing/sparking of sensitive elements, stress on beam dump
21/09/2016
G. Arduini - INFN CSN1

32. SHiP Status and Progress
SHiP Technical Proposal (April 2015) was aimed at demonstrating physics case, feasibility (experiment and facility), performance, and motivation at CERN with one year of work
Very conservative
 Comprehensive Design Study
Global re-optimization of experimental configuration
Simulation tuning
Configuration of muon shield
Geometry of decay volume and evacuation of decay volume
Re-visit detector technologies
Consolidate background rejection and extended PID for additional decay modes
Investigate extending to include invisible hidden portal decays
 First iteration of global re-optimization underway (6 months)
Implementation of Beam Dump Facility studied within context of Beyond Colliders Physics
R. Jacobsson
21/09/2016
G. Arduini - INFN CSN1

33. Potential of crystals Present collimation Crystal collimation
Crystals as primary collimators: large angles and reduced change of rigidity (diffractive losses and ion fragmentation).
Challenges for the LHC: - small angular acceptance ~2 μrad; - localization of losses up to 1.0 MJ in one single collimator absorber.
<θ>MCS ~ 3.4 μrad (7 TeV)
Amorphous (0.6 m of C)
Crystal (Channeling) (4 mm Si)
<θ> ~ 50 μrad (7 TeV)
Present collimation
Crystal collimation
Promises of crystal collimation:
1. Improve collimation cleaning efficiency, in particular for heavy ion beams;
2. Reduce electro-magnetic perturbations of collimators to the beams (impedance).
21/09/2016
G. Arduini - INFN CSN1

34. First proton channeling at 6.5 TeV
Phys.Lett. B758 (2016)
Measurement
Simulation model 1
Simulation model 2
Beam core
Collimator
Crystal
Halo
Secondary collimator position [ mm ]
Losses at collimator [ a.u. ]
Example: scan at 6.5TeV
(2) Linear collimator scan: measures the profile of the channeled halo.
(2)
(1)
(1) Angular scan: strong reduction of local losses in channeling compare to amorphous.
~1/30
Beam losses at crystal [ a.u. ]
Crystal angle [ μrad ]
Loss rates in amorphous
Reduced losses in channeling
Example: scan at 450GeV
Channeled halo
Beam core
Offset at collimator
Critical: Achieved the required angular control of better than ~1 μrad (A. Masi et al.)
21/09/2016
G. Arduini - INFN CSN1

35. Timeline for LHC crystals
: crystal test stand on beam 1 Two crystals, one per plane. Different technologies (quasi-mosaic / strip)
: New crystal test stand also on beam 2 Installation of 2 crystals during EYETS:
Aim to test new technology for goniometer with bending angles 50.0 ± 2.5 mrad
EYETS2017: Considering upgrade “old” beam 1 goniometers. If beam experience indicates the need for testing the new goniometers in both beams .
LHC second long shutdown (LS2): 4 new crystals for ion collimation This is not yet a baseline within the HL-LHC project, but we have R&D funding to prepare for it. Need for 4 crystals calls for production of ~10 units (including spares).
Crystal for LHC fixed target experiment – larger angles above 200 mrad – waiting for feedback from recent “Physics Beyond Collider workshop”
21/09/2016
G. Arduini - INFN CSN1

36. Thanks for your attention

37. Electron cloud driven instabilities
The understanding of these phenomena relies on numerical simulations (PyECLOUD-PyHEADTAIL)
In space: small beam (~100 mm) in a big chamber (4 cm)
In time: 1 ns for the e- motion, 1 to 10 s for instability development
Multi-scale problem:
Electron density during a bunch passage
e-cloud driven instability
21/09/2016
G. Arduini - INFN CSN1

38. Frequency content of the bunch motion
Simulation of e-cloud instabilities
Recent work focused on increasing the performance of our simulation tools:
Introduced multi-grid Particle in Cell solver
Exploit parallel computing through a new parallelization layer (PyPARIS)
Typical simulation study: ~400 CPU cores (8-16 cores per jobs)
Heavily relying on INFN-CNAF cluster
Allowed gaining new insight on scenarios that were previously inaccessible (e.g. 10k turn simulations for LHC at 7 TeV)
Frequency content of the bunch motion
21/09/2016
G. Arduini - INFN CSN1