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From Pipetron to LER:history of a brilliant idea and

goal of this workshop

Lucio Rossi

CERN

CARE-HHH workshop on LER

CERN -11 October 2006

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When this started…

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HHH…when I met Peter Limon…

• This paper reported how US HEP was emerging from SSC collapse.

• A “RLHC” was discussed at the ‘96 Snowmass meeting, opening a cycle that was closed in the 2001 Snowmass meeting where VLHC was put in second priority wrt ILC

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HHH… Peter presented a new type of

magnet• Invented by Bill

Foster

• 50 TeV beam with 1.8 T in a 650 km long tunnel

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HHHA parameter table and a few key issue were provided

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From VLHC … back to LHC• VLHC study were stopped in 2001• However the ongoing pipetron magnet demonstrator was allowed to continue in Fermilab (2 m long magnet with ancillaries)• Talks about using it as LHC injector started as early as 2001-02 among Bill, Peter and myself. The most sensible proposal was to drill a hole in the detectors to solve the problem of the bypass…• End 2002 - beginning 2003 all these ideas for the LHC found a frame…

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European Steering Group for Accelerator R&D

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Submitted on April 15th , at 11:35

CARECoordinated Accelerator Research in Europe

The objective of CARE is to carry Accelerator Research by integrating the European resources

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HHHWeb site: http://esgard.lal.in2p3.frUserid: esgard , password: hep

Result of the evaluation processCARE ranked at the 14th position out of 154 project (5th rank of the 58 IA)

CARE is accepted

CARE is recommended for funding at the maximum level of 15.2 M€(i.e. 52% of initial request) in the Evaluation Summary Report (ESR)

30%~.7M€

30%~0.3M€

30%~0.45M€

90%3.6M€

90%3.6M€

25%~1M€

65%~5M€

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Scope of the WP1

• 5 critical study and R&D tasks identified based on present state-of-the-art in magnet and accelerator technology :

– AMT-1 - Stability and Quench Limit of LHC at Ultimate Field and for LHC Upgrades (L+E)

– AMT-2 - Pulsed Magnets (for an SPS Upgrade) (L+E)– AMT-3 - Magnets for a LE Ring in the LHC Tunnel (E)– AMT-4 - High Field Magnet Design (L+E)– AMT-5 - Optimisation of the overall Cost of the Magnet System

for a High Energy-High Intensity Hadron Collider– Task on synchrotron radiation handling dropped

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And SPS to LHC transfer line?

• Two accelerators will shut down, presumably, after LHC commissioning:

• HERA and TeVatron: can we made the best use of their magnets? Especially the good B>5 T HERA magnets!!

• Do they adapt? (Fermilab’s are shorter)KHM has looked at : extremely difficult

P. Limon is supposed to assess feasibility and cost

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HHHThis money and energy for what ? - VII: INJ for LHC2

• Pipetron! The cheap Sc magnet for 2 T

• Iron excited by a transmission line of HTS (LN!!!)

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Pipetron - Cont. 2• Invented in Fermilab by W. Foster around 1995-96• Strong push to arrive to a model then put aside by the lab after the decision of

2001 to postpone VLHC.• Test of a 1 m long model in 2004• Cable might be done in MbB2 !! As well.

Courtesy ofH. Piekarz (Fermilab)

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LHC

LEP

Merci a M. Muttoni

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Space LEPNew

Low Energy ring

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What we have learnt so far

• This project was born because a new magnet design was available and somebody was trying to use it.

• Although this might become an enabling technology, the real problem proved to be not in the ring magnets but elsewhere

• Magnets are feasible but what about the collider feasibility?

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Rational for an LHC injector• The LHC main dipoles have sizable (dynamic)

multipoles at the injection field.• The LHC spends 20 mins at the injection plateau

while being filled by the SPS• Bunch intensity and emittance are limited by these• These limitations can be taken out by injecting at a

higher energy (x 2) and in a shorter time (< 1s)• An injector ring would also allow for RF gymnastics

like bunch coalescing to overcome the intensity limitations of the injector chain

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Hot Questions• Feasibility of the various schemes near the

detector– Bypass tunnel– LHC detector beam pipe– Through detectors (is this really unacceptable?)

• Safety and reliability• Any show stopper (impedance?, lattice?,

space available in the ring?)• Low magnet cost. Does this really translate in

a low cost ring?

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Main Goal

• To assess if it is technically worth to explore the idea more deeply.

• To assess if it might contribute significantly to the LHC luminosity, (preparing the ground for an LHC energy upgrade is good but is more far into the future

• Today the comparison with competing schemes (SPS upgrade) is premature: The LER has to prove it is useful and possible before trying to prove that is better than…