Amazing particles and light

2 March 2007

Swapan Chattopadhyay reflects on the extraordinary fundamental value of accelerators.

Promising developments in hadronic physics, microwave superconductivity, free-electron lasers and efficient energy-recovery techniques in accelerators were beckoning me – after 25 colourful years at Berkeley, including two spent at CERN. I was also concerned about the longevity of a profession in which I had personally invested. I had seen the attrition of talents, many of whom I mentored, to other professions, driven by socio-economic realities of large particle accelerators. This inspired me to motivate accelerator-science practitioners to diversify their portfolio by developing the small and mezzo-scale engines that would drive emerging nano- and bio-sciences. Today, on the eve of another personal transition as I prepare to take the helm at the UK’s Cockcroft Institute, new developments and challenges once again invite comment.

I observe a few key developments contributing at the frontier of “discovery”, while others attest to “innovation” and “diversification”. These include: development of electron, proton and ion beams of unprecedented precision based on normal and superconducting material technology and advanced feedback control; diversification and growth of synchrotron radiation sources worldwide; evolution of sophisticated table-top laser-plasma acceleration techniques with necessary control to produce giga-electron-volt electron beams; demonstration of self-amplified spontaneous emission for the planned X-ray free-electron lasers; demonstration of efficient energy use and recovery in superconducting linacs; and production of ultra-short femtosecond flashes of electrons, infrared light and X-rays for studies of ultra-fast phenomena – to name but a few.

We have consolidated the “discovery” sector and diversified the “innovation” sector

I also admit to occasional sombre worries that perhaps accelerators will be just a passing moment in history. But I was always awakened by the realization that particle accelerators have been and must continue to be singularly distinctive instruments of discovery and innovation, in various measures. What we are witnessing is a mere partitioning of the balance between these values in the context of the evolving human condition. We have consolidated the “discovery” sector and diversified the “innovation” sector. The fundamental value of accelerators, articulated in my 2002 Viewpoint, remains invariant: they package and focus energy and information in patterns of space–time bursts to serve a multitude of human pursuits – hence their universal, timeless appeal. Amazing particles and light, carrying focused energy and information in special staccato-fashion, beam into matter and life, illuminating what our eyes do not see and manipulating what our hands cannot.

Throughout the 20th century, fundamental discoveries were enabled by bold conception and realization of ever-larger particle accelerators, which today must be consolidated into just a few carefully selected facilities so large that they can only be supported internationally. Hence the emergence of but a few grand future machines: the Large Hadron Collider, the X-ray free-electron lasers, a potential International Linear Collider (ILC- or CLIC-based), and neutrino/muon facilities. This consolidation is a must for mastering the global resources necessary to discover fundamentals at the core of the physical world: hidden dimensions, symmetries and structures; origins of mass, dark matter and dark energy; unification of gravity; and exotic states of matter.

In parallel with that consolidation, we continue to anticipate tremendous diversification in the innovation sector of clever techniques and merger of technologies in creating unique bursts of particles and light. These efforts will lead not only to novel affordable scientific devices (for example, energy-recovery and laser-plasma-based compact high-brightness particle and light sources), but also to an increasing set of affordable instruments and processes that more directly enrich our everyday lives (such as novel medical imaging, diagnostics, therapy and radiation oncology; micro-machined instruments for use in medicine, scientific research, information technology and space exploration; designer nano-materials; and knowledge of complex protein structures for drug discovery).

The vision is one of discovering the secrets of the hidden energy and matter in the universe’s evolution; of understanding the protein as the molecular engine of life through studying its energetics and structural folding; of innovating new eco- and bio-friendly materials for human use; and of eliminating radioactive waste and dependence on fossil fuels. Extraordinarily clever particle accelerators drive this at all scales from “small” to “mezzo” to “grand”.

Is this just a dream? Inspired by US poet Carl Sandburg, I respond: “Nothing happens, unless first a dream.”

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