RLIUP (summary)

Review of LHC and Injector Upgrade Plans

Excerpts from the presentation of S. Myers, November 7th, 2013

History• Present “10 year” schedule was

– proposed and developed at a time when we had much less information than now

– and was not developed in a self-consistent (iterative) way.Comment on Machine Performance• In the early years of operation, spectacular performance increase can be

attained by pushing accelerator physics limitations (intensity, beta*, emittance …)

• After some years of operation, these possibilities become exhausted• Slower performance increases then comes by upgrades and small (%)

improvements on a multitude of fronts including machine availability etc• LHC is entering this new phase (upgrades and small improvements

on many fronts)• Both need careful planning

From the presentation of S. Myers, November 7th, 2013

Answers (from RLIUP) to Important Questions• Radiation Limit for detectors and machine– 300 – 500 fb-1 (machine possibly more critical)

• LS2 needs 18-24 months• LS3 needs 24-36 months• Run2 should last for 3 years

From the presentation of S. Myers, November 7th, 2013

Important Comments• (A. B.1st Talk), ESB: Europe’s top priority should be the exploitation of the full

potential of the LHC, including the high-luminosity upgrade of the machine and detectors with a view to collecting ten times more data than in the initial design, by around 2030.

• (F.G. 2nd Talk)– The STRONG physics case for the HL-LHC with 3000 fb-1 comes from the

imperative necessity of exploring this scale as much as we can with the highest-E facility we have today (note: no other planned machine, except a 100 TeV pp collider, has a similar direct discovery potential). ……..

– We have NO evidence of new physics. implies that, if New Physics exists at the TeV scale and is discovered at √s ~ 14 TeV in 2015++, its spectrum is quite heavy it will require a lot of luminosity (HL-LHC 3000 fb-1) and energy to study it in detail ..implications for future machines (e.g. most likely not accessible at a 0.5 TeV LC)

– HL-LHC is a Higgs Factory. It can measure the Higgs coupling with an accuracy of a few %

From the presentation of S. Myers, November 7th, 2013

Strategy• LHC has been constructed, operated and will continue to be operated on a

CONSTANT BUDGET• We have a beautiful scientific facility, unique in the world.• The community has invested (and are investing) a huge amount of their

resources in this unique facility both for construction and for operation.• The FULL operational costs integrated over the future operating years

exceeds the proposed upgrade costs. Hence we should operate this unique facility in the most efficient way possible.

• Both Upgrades, LIU and HL-LHC, should aim for the maximum useful integrated luminosity possible

• LS3 should come as soon as possible in order to maximize the integrated luminosity (every delay by one year of LS3 “costs” 200fb-1)

• LS2 should not delay LS3.

This means

The goal of 3000fb-1 by 2035 is challenging but attainable

From the presentation of S. Myers, November 7th, 2013

Summary of Summary of Summaries (list)

• Performance– Pile-up and pile-up density (detectors and machine)– 25ns: e-cloud, scrubbing, short term mitigation, long term

solution– Machine availability: minimise down time, speed up turn

around

• Shutdowns– Plan well in advance: global resource loaded schedule, identify and

rectify weaknesses in expertise areas– Design for ALARA; minimum intervention time and use of correct

materials (actiwys)

• Beam Energy– Investigate increase of maximum beam energy in the medium term

(?? Use of 11T magnets for collimation??)

From the presentation of S. Myers, November 7th, 2013

7

Shutdown schedule until 2035Scenario 1

from 2015 to 2035: beam = 57% % of time

Oct. 29th, 2013 RLIUP workshop = Baird, Foraz

LS5

LS4

LS2

LS3

K. Foraz

8

Shutdown schedule until 2035Scenario 2

from 2015 to 2035: beam = 54 % of time

Oct. 29th, 2013

LS2

LS5

LS4LS3

YETS+6

RLIUP workshop = Baird, Foraz

K. Foraz

What could stop us?• Potential causes of mechanical failures of SC magnets– Mechanical fatigue on coil, structure, busses:

• Powering cycles: 104 per magnet• Thermal cycles: a few for the LHC

– Singular events and associated thermal and electrical stress:• Quenches: order of 10 per magnet• Heater discharges (triggers): order of 10 per magnet

– Radiation and associated degradation of mechanical and electrical strength:• Magnet in the triplet region (Point 1 and Point 5)• Magnets in the collimators region (Point 7)

L. Bottura

What could stop us?• Electromechanical failures:

– An MTBF of 400…500 years has been estimated for the LHC superconducting magnets

– This translates in approximately 3…4 magnet electrical NC’s per year of operation, and at least 10…15 magnets exchanges every long shutdown need to have tools to evaluate (on-line) effect of non-conformities

– Given the estimated MTBF, the probability of electrical failure of one of the triplet magnets within the next 10 years of operation is 3 %, i.e. 1 magnet

• Questions:– Ageing?– Impact of number of cycles?– Experimental magnets

L. Bottura

What could stop us?

• Expected dose by LS3 (300 fb-1)– Range of 27 [18…40] MGy in the Q2– Range of 20 [13…30] MGy in the MCBX

• IT may experience mechanically-induced insulation failure in the range of 300 fb-1 (LS3 ± 1 year) consistent with previous analyses.

• Effects: – Premature quenches (cracks in end

spacers)– Insulation degradation (monitor on line)– Mechanical failure (nested coils in

MCBX)

L. Bottura• Radiation and Inner Triplets

What could stop us?• Radiation on the warm magnets (collimation area)• Expected dose by LS3 (300 fb-1)

– Range of 80….90 MGy in the MBW and MQW• Actions have been proposed and approved to avoid

insulation failure in the period LS2 to LS3• Starting in LS1

Shield inserts and masks for MQW, by courtesy of P. Fessia

L. Bottura

What could stop us?

• Point 1 • Point 5

Ambient dose equivalent rates in µSv/h at 40cm extrpolated from measurements after LS1

346 250 96(max)

158(max)

50 31 432408 96 96

(max)48 173 53 24

Radiation to the personnelThe triplet will be a limited stay areaAccess and work in the triplet and collimator area will be subject to ALARA-level III rulesMeasures must be taken to reduce intervention time in LS3 at the latest

S. Roesler, The Panorama of the Future Radioactive Zones from Now to 2020, May 2013https://indico.cern.ch/conferenceDisplay.py?confId=233480

L. Bottura

My summary

• The upgrade program is fully supported by the CERN management

• We will change the working mode in the LHC, approaching what is done in the injectors

• Radiation issues are coming up, especially radiation dose during interventions, and we need to prepare for this