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The idea of following CERN's Large Electron–Positron Collider (LEP) with a Large Hadron Collider (LHC), housed in the same tunnel, dates back at least to 1977, only two years after LEP itself was conceived. The importance of not compromising the energy of an eventual LHC was one of the arguments for insisting on a relatively long tunnel in the discussions that led to the approval of LEP in 1981.

Early discussions of the LHC were dominated by sometimes acrimonious competition and comparisons with the proposed 40 teraelectronvolt (TeV) Superconducting Super Collider (SSC) in the United States. Serious work on the SSC was kick-started by American reactions to the discovery of the carriers of the weak force, the W and Z bosons, at CERN in 1983. CERN's discovery was greeted by a New York Times editorial entitled "Europe 3, US Not Even Z-Zero", and a call from the President's science adviser for the United States to "regain leadership" in high-energy physics.

Viewed from Europe, this was provocative. 40 TeV is more than twice the energy that could possibly be reached by a hadron collider installed in the LEP tunnel, and many Europeans suspected that this was why 40 TeV was chosen. Furthermore, CERN's leadership favoured the next really large accelerator being an inter-regional facility. There was agreement on the vital importance of being able to explore new phenomena of up to 1 TeV — the energy below which the Higgs boson, or whatever else generates the mass of all particles, should be discovered. But how much better this could be done at the SSC than at the lower energy LHC was hotly debated. The energy domain that can be explored by a hadron collider is less than that of the accelerated particles, which is shared between their constituents. However, the much higher intensity (or luminosity, in the terminology of particle physics) planned for the LHC could in principle compensate for it having lower energy than the SSC — with denser bunches of accelerated particles there is a greater chance of collisions between constituents with large fractions of their parents' energy — although another decade of intensive research and development was needed to establish that experiments are possible at such high luminosity.

The extreme European view was that the SSC was irresponsible as it would cost five times as much as the LHC without providing much more physics. A global plan, on the other hand, would provide complementary facilities — a large linear electron–positron collider in the United States and the LHC at CERN, which would use the LEP tunnel and other existing infrastructure — and would therefore be much cheaper than the SSC. A typical American response was to refute the claim that the LHC could do much the same physics for one-fifth of the cost, and to meet with scepticism any concern for American taxpayers. Meanwhile, senior Japanese physicists who argued that the SSC should be international were told that it was a national facility. They did not forget this when the United States later asked Japan to contribute US$2 billion.

I thought the extreme European position was unrealistic. The United States wanted a new project that could reach 1 TeV as soon as possible and a large hadron collider was the only realistic option at the time. The technology was not then available to build a 1 TeV linear collider: the 0.1 TeV linear collider at Stanford, the world's first, had not been built, and even the International Linear Collider now being proposed will initially reach only 0.5 TeV. On the other hand, my experience as adviser to the Kendrew Committee, which was then considering whether the United Kingdom should remain in CERN, had made me acutely conscious of growing pressure on funding for particle physics. I doubted that the SSC — which seemed profligate to me, despite its enormous potential — would ever be funded.

In fact, the SSC was endorsed by President Ronald Reagan in January 1987, with a price tag of $4.4 billion. In May 1990, when the cost had risen to $7.9 billion, the House of Representatives voted to limit the federal contribution to $5 billion, with the rest to be found from the state of Texas ($1 billion) — the proposed site of the SSC — and from overseas (where none was found). The SSC was defeated in the House in June 1992, but later revived by the Senate; this happened again in June 1993, by which time the General Office of Accounting estimated the cost as $11 billion. It was cancelled in October 1993
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The right machine for the future
Meanwhile at CERN, research and development started on the very demanding LHC magnets in 1988. This was recommended by a Long Range Planning Group chaired by Carlo Rubbia, who shared the 1984 Nobel Prize in physics for the discovery of the W and Z bosons, and who became Director-General of CERN in 1989. Rubbia argued that the LHC would provide healthy competition for the SSC at a relatively modest cost and that it would be more versatile and bring important additional new physics. As well as accelerating protons, it would be able to accelerate heavy ions to world-beating energies at little extra cost, and LHC protons could be collided with electrons in LEP at much higher energy than in the Hadron Electron Ring Accelerator (HERA) then being built in Hamburg (this option was abandoned in 1995 when it was decided that, after it was eventually closed, LEP should be removed to make it easier to install the LHC).

Rubbia's powerful advocacy and a series of workshops built up pan-European enthusiasm for the LHC, although not everyone was convinced that the collider was justified, or would ever be funded, in parallel with the SSC. I swallowed any doubts and supported the LHC as a member (1986–92) and chairman (1990–92) of CERN's scientific policy committee. I thought the versatility argument was good, and that the LHC should be supported — at the very least as an insurance policy in case the SSC ran into trouble.

In December 1991, the CERN council adopted a resolution that recognized the LHC as "the right machine for the advance of the subject and the future of CERN" and asked Rubbia to come forward with a complete proposal before the end of 1993. I was due to succeed Rubbia as CERN's Director-General at the beginning of 1994, and in early May 1993 he handed me the responsibility of preparing and presenting the LHC proposal. The outlook was not encouraging: a new, detailed costing was significantly bigger than previous estimates; the personnel requested by CERN group leaders to build the LHC would have required a 20% increase in staff; attitudes to high-energy physics were hardening in several CERN member states; and the CERN council had just agreed to a temporary reduction in Germany's contribution on the grounds that reunification was proving very costly.

Bid for approval
Over the summer and autumn of 1993, Lyn Evans, by then nominated as LHC director, proposed several modifications to the design that reduced the cost, and with the help of many others I identified reductions in the rest of the CERN programme that would free up money and manpower. Costing was difficult as this was before most of the research and development for the LHC had been completed — for instance, the first full-length dipole magnet was not tested until December 1993. It was also before approval of the experimental programme, which became more ambitious after a large influx of American researchers joined proposals for LHC experiments after the SSC was cancelled. Our 1993 costing therefore underestimated the eventual specification and cost of the underground areas that were to house the experiments.

The plan I presented to the CERN council in December 1993 foresaw LHC construction, with commissioning in 2002, on the basis of a humped budget, with full compensation for inflation of materials costs. The hump was to come from a mixture, still to be defined, of a general budget increase, additional voluntary contributions from some member states and contributions from non-member states. The plan was generally well received, although it was clear that Germany and the United Kingdom were very unlikely to agree a budget increase, and we were asked to come back with proposals to reduce costs further and indications of how much non-member states might be willing to contribute.

We developed proposals to delay LHC commissioning until 2003 or 2004, stage the construction of the detectors and, while maintaining priority for LEP and the very ambitious LEP upgrade (the first phase of which was not complete), reduce other parts of the CERN programme to a bare minimum over the coming years, with complete closure for one year. In June 1994 we requested approval of the LHC from the CERN Council. The date of commissioning was to be decided later, depending on what voluntary and non-member state contributions were obtained. Encouragingly, a US panel had by then recommended that "the government should declare its intention to join other nations in constructing the LHC" (although the suggested contribution was disappointingly small), and positive signals had been received from Japan, Russia and India. Seventeen member states voted to approve the LHC. The vote was left open, however, because the other two member states — Germany and the United Kingdom — would not accept the proposed budgetary conditions, and demanded substantial additional voluntary contributions from the host states (Switzerland and France), who, they considered, gained disproportionate benefits from CERN.

The missing-magnet machine
Over the next six months, difficult discussions ensued between CERN, the host states, and Germany and Britain (at one point, the Director General of the UK Research Councils, John Cadogan, told me I would be "staring into the abyss" if we could not reduce the cost of the LHC). Some movement on the part of France and Switzerland was beginning to ease the position when Germany and Britain announced that they could only approve the LHC under a planning assumption of 2% inflation to be compensated by 1% indexation — in other words, a 1% annual budget reduction in real terms — and continuation of the German rebate for some years. These conditions seemingly made it impossible to launch the LHC while upgrading and exploiting LEP, and maintaining CERN's small programme of excellent fixed-target experiments.

Our response was to propose keeping down the annual cost by building a 'missing-magnet machine', in which a third of the dipole magnets would be omitted in a first phase, thereby saving some 300 million Swiss francs (US$240 million). The machine would have operated at two-thirds of full energy for some years, before the remaining magnets were installed. Although the final cost would have been more, and results from phase two would have eclipsed the physics from phase one, the two-stage LHC would nevertheless have been a world-beating facility — and it was the only option available.

I was asked whether the two-stage LHC would be viable under the proposed budget conditions. My first reply amounted to a "yes, but...". It was made clear that qualifications would prevent approval. So I took a deep breath and replied yes, adding that the conditions would be acceptable if accompanied by an assurance that any contributions from non-member states would be used to speed up and improve the project, not to allow reductions in the member states' contributions. The CERN council explicitly gave this assurance, and on 16 December 1994 approved the LHC, on the basis of a two-stage construction plan, to be reviewed in 1997 in light of what contributions had been obtained from non-member states, and of the budget conditions required by Germany and Britain, including the continuation of the German rebate. Generous French and Swiss offers to make in-kind contributions and to increase their contributions by 2% a year were crucial factors.

Reassured by a letter from the then British Minister of Science, David Hunt, which described the conditions as "realistic, fair and sustainable", it seemed that all that remained was to try to identify further internal cutbacks, so as to turn our reply to the question of viability into a genuinely unqualified yes, and to seek contributions from non-member states. This we did. Negotiations with Japan — which made the first-ever substantial contribution of a non-member state to a CERN accelerator in June 1995 — and with Russia, India, Canada and the United States went well. By the middle of 1996, we were becoming confident that single-stage construction would be possible, and raised with the council the possibility of bringing forward the 1997 review to December 1996.

Then, in July 1996, out of the blue, the German government announced that, to help ease the financial burden of reunification, it intended to reduce all international science subscriptions. A particularly large cut (8.5% for two years and 9.3% thereafter) was proposed for CERN, despite the fact that Germany was already enjoying a 'reunification rebate'. The possibility of limiting the reduction to just the German contribution was scuppered when the UK government announced that, the minister's letter notwithstanding, it had always seen the 1997 review as another opportunity to look for reductions in the CERN budget. It called for "the largest possible reduction" claiming that this could be achieved "without damaging CERN's scientific mission or endangering the LHC". The particle-physics community in the United Kingdom was reluctant to challenge this assertion, as they were told that reductions in the CERN budget would be their source of funding for participation in LHC experiments.

Forwards through deficit
CERN's public response to the proposed budget cut was muted by fear of shaking the confidence of the non-member states, who had been assured that their contributions would not be used to allow reductions in the member states' contributions. The United States, which had repeatedly asked for reassurances on the viability and sustainability of CERN's planning and funding, was a particular worry. A US contribution to the LHC, significantly larger than suggested by the 1994 panel, had just been negotiated, but a formal agreement had not yet been drafted, let alone signed.

The subsequent discussions were rough. At one stage, Germany threatened to leave CERN if its demands were not met exactly, and even prepared a letter of withdrawal that leaked to the press. There were suggestions that the United Kingdom might also use the threat of withdrawal as a negotiating tactic. I repeatedly told the CERN council that cuts of the magnitude proposed would destroy the LHC's viability, although — as inflation had been zero since 1994, thanks to the strength of the Swiss franc — we had built up a reserve of around 2% in the budget, which could be sacrificed without making matters worse than they had been at the end of 1994. Drawing attention to this reserve was perhaps a tactical error, as it seemed to make a 9% reduction somewhat less out of reach. Given the United Kingdom and Germany's determination, however, I don't think it made any difference to the final outcome.

The crunch came in October when with Horst Wenninger, who played a central role in putting together the LHC proposal, I met the German minister with responsibility for CERN, Jürgen Rüttgers. We explained that the LHC could not survive the proposed budget cut. Rüttgers was uncompromising, but finally asked whether there was any conceivable way to avoid this conclusion. We replied that it could be avoided if CERN were allowed to take out loans, an idea that Germany had previously vetoed: deficit financing would be extremely risky, but would be acceptable if accompanied by clear acknowledgement of the risks by the CERN council and approval of single-stage construction, which was not only desirable scientifically, but necessary to ensure the contributions required from the non-member states.

A sting in the tail
During the next meeting of delegations to CERN, Germany declared that "a greater degree of risk would inevitably have to accompany the LHC". Others, while accepting deficit financing, acknowledged the risks in similar or stronger terms, and single-stage construction of the LHC, with completion foreseen in 2005, was approved on 20 December 1997. After intensive lobbying of other member states, the accompanying budget reduction was marginally smaller than requested by Germany. The CERN council also imposed a one-year 2% 'crisis levy' on the salaries of CERN staff, even though they had hardly risen since 1993, while further efficiency savings and economies were sought.

We duly got on with this job, but there was a major distraction and sting in the tail. The new chairman of the US House of Representative's Science Committee, James Sensenbrenner, who was suspicious of international projects as a result of his experience with the International Space Station, declared that the proposed agreement between the US Department of Energy and CERN was unsatisfactory. I believed that without the United States, the hard-won European agreement to build the LHC might unravel, whereas their involvement would make it secure. Some very anxious months ensued. In the end it turned out that Sensenbrenner was satisfied with modifications that strengthened the United States' protection against unforeseen events without changing the magnitude of its contribution, and a US–CERN agreement was finally signed in December 1997.

When I left CERN at the end of 1998, the final phase of the LEP upgrade was still being completed, there was a vigorous ongoing LEP programme, and agreement had been obtained to operate LEP for an additional, final year in 2000. Nevertheless, it was clear that the time had come to prepare to reorganize CERN for the post-LEP era on a basis focused on the LHC project. On the face of it, things were going well, half the LHC contracts (by value) having been placed, at prices (in aggregate) just below the estimates.

It was obvious, however, that the budgetary position was extremely fragile. The deficit financing of the LHC was hyper-sensitive to small changes in the timing of contracts. Although the assumptions on timing, manpower and costs, made under great pressure in 1994 and 1996, had not been unreasonable, they had tended to be on the optimistic side, and the LHC proposal had contained no contingency funding because it would not have been accepted by some of the CERN member states. Furthermore, although the tenders for the underground civil engineering had come in below expectations, such contracts are almost always subject to revisions due to unexpected geological conditions, and the contracts for the most demanding and largest single item — the dipole magnets — had not been placed.

The LHC is an extremely challenging project, and the delays that were later produced by problems with the civil engineering and other factors should not have been a surprise. Given that it was approved in the research and development phase with no contingency, and given the 1996 discussion of risks, the 2001 revelation that the LHC would go significantly over budget should also not have been a surprise — although the lack of any warning made it a huge shock.

Lessons for the future
What lessons can be learned from the LHC saga? First, the SSC debacle strongly suggests that new projects should, if possible, be sited at existing laboratories, where they can use existing infrastructure and be spared the challenges of setting up a new laboratory and having to recruit all the key staff from scratch. Second, potential partners should be brought in at the start on equal terms or, if this is not possible, their contributions should bring added value, and they should be offered a 'voice' in the governance, as was done for the LHC. Third, approving large projects is particularly difficult for international organizations: at any time at least one partner may have economic difficulties or be out of sympathy with the organization. Fourth, stability is crucial for successful planning and execution of major projects. The events of 1996 upset orderly management, as well as shaking the confidence of CERN's staff and of potential partners in the non-member states.

Finally, it is not wise to approve projects without contingency on the basis of optimistic assumptions, although it may be worth it if — as in the case of the LHC — this is the only way to get them approved. This point was made in extreme terms, which certainly do not apply to the LHC, in a 2003 supplement to The Times of London on the world's great construction projects, which asserted that "If those involved didn't lie about the cost, they would never be built."

The LHC is now almost built, thanks to the dedication of the CERN staff, at a final materials cost only some 20% more than foreseen in 1993; not bad for a high-tech project approved in the research and development phase. It is a fantastic project, and I am confident that the LHC will perform superbly.

Correspondence to the author (Email: chris.llewellyn-smith@ukaea.org.uk).

Release link: http://www.interactions.org/cms/

Tags: Large Hadron Collider (LHC) , long tunnel , teraelectronvolt , Superconducting Super Collider , Z-Zero ,

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