Science of NSCL

Schematic picture of an atom, which shows the nucleus and electron cloud.

The primary goal of our scientific endeavor is to unravel the mysteries that reside at the center of atoms, in atomic nuclei. There are 118 known elements in the universe, such as carbon, calcium, iron and gold, each defined by its own unique number of protons inside its nucleus. For example, calcium has 20 protons. Adding or removing neutrons can create unstable isotopes, which only survive for a limited time before decaying to stable nuclei. At present about 3200 different nuclei in total have been discovered. In the case of Calcium, isotopes with as little as 14 neutrons and as many as 38 neutrons have been discovered.

Researchers at NSCL work at the forefront of the research into these unstable nuclei. Such research is motivated by the quest to solve mysteries about how the different isotopes were formed and why certain nuclei exist and others don’t. This requires gaining a fundamental understanding of forces that bind separate protons and neutrons into nuclei.

The Chart of the Nuclei shows stable and known unstable nuclei, as well as “terra incognita” where no data are available. The image below shows Calcium isotopes (which have 20 protons), including the 6 stable isotopes with 20, 22, 23, 24, 26 and 28 neutrons. Calcium found on earth is overwhelmingly (96%) ⁴⁰Ca. Many unstable calcium isotopes have been discovered, providing a wealth of information for nuclear scientists.

A chart of nuclides, which shows observed nuclei and terra incognita

The physics of unstable isotopes and the reactions they undergo are very important for understanding the nature of stars and their evolution from birth to often cataclysmic death. Such understanding in turn explains the abundances of isotopes that formed our solar system and ultimately led to life on earth.

Much of the knowledge gained from research performed at NSCL has applications in day-to-day life. Such knowledge is for example gained from research in accelerator physics and isotope production that are important for medical imaging and cancer treatment, the development of sensitive radiation detectors that have applications in homeland security, and to the creation of computational techniques that have uses in applied sciences.

NSCL houses the Coupled Cyclotron Facility which produces fast intense beams of stable nuclei at approximately 40% of the speed of light. These nuclei are fragmented by colliding them with a thin production target, generating many different types of isotopes. An in-flight separator purifies the beam to the desired species. This fast beam of rare isotopes can be used directly in experiments, or “stopped” for experiments that require very high precision. In the latest addition to the research capabilities of the Laboratory, the stopped unstable nuclei are reaccelerated to produce a high-quality beam of relatively slow unstable nuclei. Experiments with such beams are, amongst others, very important for understanding nuclear processes in stars. In the future, the Coupled Cyclotron Facility will be replaced by a powerful linear accelerator, and NSCL will become FRIB: the Facility for Rare Isotope Beam.

For more details, TAKE A VIRTUAL TOUR OF THE LABORATORY

A layout of the beamline, starting with heavy ions hitting the target.

An excellent way to illustrate the diverse impact of the research performed at NSCL is to look where students who conducted that work are being employed. Some will continue their career in fundamental research but many follows career paths in nuclear medicine, airport security, environmental protection, weapons stewardship, national security, nuclear fusion, areas related to the radiation safety of space travel, and even in the financial sector, where the ability to deal efficiently with big data sets, which are often found in nuclear science research, is very important.