The Life of the LHC and the Death of the SSC

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The Life of the LHC and the Death of the SSC

A Comparison of Two High-Energy Physics Gigaprojects


Michael Riordan

An underground tunnel dug for the planned SSC. Courtesy of Fermilab Archives.

In October 1993 the US Congress canceled the Superconducting Super Collider, or SSC. The government had spent $2 billion on this massive project, then the largest basic-science project ever attempted. With a tunnel over 50 miles in circumference located south of Dallas, Texas, the massive proton collider was designed and promoted to reestablish American leadership in high-energy physics by discovering the long-sought Higgs boson.1

In retrospect, the Large Hadron Collider (LHC), built from 1997 to 2008 at the CERN laboratory near Geneva, Switzerland, was more appropriately sized to discover this particle, evidence of a field that imbues other elementary particles with mass. When the SSC was proposed in the mid-1980s, the likelihood of finding this particle at a mass as low as 125 GeV was not very well appreciated.2 Only in the late 1980s did theories involving supersymmetry begin to suggest that such a low-mass Higgs boson might occur.3 But by then the SSC die had been cast—in favor of a gargantuan 40 TeV (40 trillion electronvolt) collider that would be sure to discover this elusive quarry, or whatever other mass-generating mechanism nature might prefer.4

Thus there is much to be learned about how to pursue big science projects by investigating why the SSC failed and the LHC succeeded.

For one, big science projects require strong leadership and project management. The LHC encountered its own set of serious difficulties. Physicist Lyndon Evans guided the project throughout its construction, even as costs of the collider components and additional tunneling increased from 2.8 to over 4.3 billion Swiss francs (not including costs of labor or the tunnel, which already existed). The CERN directorate never lost faith in Evans and his team. In stark contrast, the SSC project witnessed a succession of four project managers before John Rees, an accelerator physicist from the Stanford Linear Accelerator Center, began to bring the unwieldy project under control in January 1992. But Congress lost patience and killed the project 21 months later, after the SSC’s estimated cost surpassed $10 billion.

Despite belated efforts to internationalize it, the SSC was largely a US national project, and major foreign contributions were consequently hard to obtain. This was not such a problem with the LHC, which was billed as an international project from the outset. In the mid-1990s, its CERN advocates lined up funds from Canada, China, India, Israel, Japan, Russia, and the United States before the project received official approval in 1996. That permitted Evans to proceed with a full-scale design aimed at reaching proton collision energies up to 14 TeV.

Another factor in the LHC’s success was CERN’s governing body or Council, which insulated the project from external political machinations. This kept project control directly in the hands of the physicists, who best understood its scientific goals. Control of the SSC construction was essentially ceded by the physicists to engineering managers from US defense contractors, who treated the huge project more like building an aircraft carrier than establishing a world-class laboratory for high-energy physics.

Weeds grow at the abandoned site meant for the Superconducting Supercollider. Photo courtesy of Ich Weiss es nicht at the English Wikipedia Project.

The CERN Council also allowed other European scientists to have a say in the LHC project. Science ministers from various member nations could hold off on giving approval until its impact on their national science budgets was acceptable. In the United States, there was no way for other scientists—for example, condensed-matter physicists—to have any such say in the impact of the SSC project on their research fields, except to complain publicly before Congress and in opinion pieces published in major newspapers and magazines.

A map showing the planned path of the SSC's particle accelerators and tunnels, including the main ring circling Waxahachie. US Department of Energy.SSC advocates in the Department of Energy and the US high-energy physics community greatly underestimated the difficulties—both managerial and political—of establishing a new scientific laboratory and a multibillion-dollar collider in Texas. By contrast, CERN had been gradually building one machine after another as extensions of its physical infrastructure, realizing the substantial cost savings of recycling old projects into new ones. By reusing an existing 27 km tunnel, LHC builders could concentrate attention on solving the problems of developing the high-field superconducting magnets that had so vexed the struggling SSC project and added to its burgeoning costs.

This conservative approach also meant that, unlike the SSC project, CERN did not have to assemble a new human infrastructure of physicists, engineers, designers, technicians, and other personnel. It turned to the laboratory’s well-oiled team of some of the most experienced machine builders in the world. They recognized each other’s expertise and worked steadfastly toward a common physics goal, laying the groundwork for the celebrated Higgs boson discovery in 2012. //

1. For details, see M. Riordan, L. Hoddeson, and A. W. Kolb, Tunnel Visions: The Rise and Fall of the Superconducting Super Collider (Chicago: University of Chicago Press, 2015).

2. This is equivalent to the mass of a cesium atom, as 1 GeV is equal to 0.938 proton mass, according to Einstein’s famous equation E = mc2.

3. By the end of the 1990s, the Fermilab discovery of the top quark with a mass near 175 GeV, when employed in fits to precision measurements of other particle physics parameters, suggested that such a light Higgs boson should occur, with a mass less than 200 GeV. That realization came well after the SSC had been terminated but before the LHC detector designs were completed and their construction had begun.

4. According to Einstein’s E = mc2, 1 TeV is approximately 1,065 proton masses, or about the total mass of five bismuth atoms.

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