Role Of Isotope Separator On Line Device (ISOLDE) Facility In Large Hadron Collider, CERN

Image Credit: CERN

Know About The Isotope Separator On Line Device (ISOLDE) Facility Present At CERN

The Large Hadron Collider (LHC) is the biggest, most advance and complex particle accelerator facility situated at CERN, Geneva and the greatest symbol of excellence achieved by mankind in the field of science and technology. The LHC came into function on 10th September 2008 at CERN, Geneva and it is the largest and most powerful particle accelerator in the world. It took over a decade by thousands of scientists, engineers and technicians from different countries to develop this complex particle accelerator facility. The LHC runs for 27 kilometre along a circular ring like tunnel and lies 175 metres below the ground. The entire ring like facility comprises of numerous superconducting magnets and some accelerators which immensely boost the energy of the particles along the way. Beams of two extremely high-energy particles like protons, travelling close to the speed of light along opposite directions are made to collide with each other. The superconducting magnets and accelerators provide the particles with near-light speed which in turn helps in the collision of two high-energy particles of same nature by overcoming the drastically huge inter-atomic repulsive forces. The two beams travel along opposite directions in separate ultra-high vacuum tubes with superconducting electromagnets providing strong magnetic fields to guide and focus the beams along the accelerator ring and then finally compact the particles in the beam close together to increase the chances of collisions.  The superconducting electromagnets comprise of special coils out of electrical cables that can operate in superconducting state and thus can efficiently conduct electricity without any resistance or energy loss. Massive amount of heat are generated from the electromagnets and accelerators and to keep them in operation, they are needed to be continuously cooled to a ultra-low temperature of -271.3°C using liquid helium distribution system connected to the accelerator. The accelerator and all its infrastructures are controlled under a single roof from the CERN Control Centre which operates the beams inside the accelerator making them to collide at four positions along the ring where the four particle detector lies, namely ATLAS, CMS, ALICE and LHCb.

Among the several components of this complex particle accelerator, Isotope Seperator On Line Device (ISOLDE) facility is one of the main component which is in operation for more than 50 years. It was first proposed at the 600 MeV Proton Synchrocyclotron in 1964 and the first experiments started 1967. It is designed as the unique source for production of low energy beams of radioactive isotopes to investigate the structure of atomic nuclei thus fulfilling our dream of changing one element into another and giving us exposure to the vast territory of atomic nuclei. Wide variety of atomic fragments are obtained by directing high intensity proton beam from the Proton Synchrotron Booster (PSB) into specially developed thick targets. The low energy beam generated for different experimental stations are formed by ionizing, extracting and separating nuclei based on their mass using various devices. The beam can be further accelerated up to 7.5 MeV/nucleon using the new linear accelerator High Intensity and Energy-ISOLDE (HIE-ISOLDE) which came into function in October 2015. The new upgrade will allow to accelerate up to 10 MeV/nucleon. The accelerated beams are directed into array of high resolution germanium detector known as the Miniball station. It is specially designed for low multiplicity experiments with low-intensity radioactive ion beams (RIB) and the array consists of 24 six-fold segmented, tapered and encapsulated high-purity germanium crystals. In a wide range of research domains starting from studies of nuclear structures, atomic physics, nuclear astrophysics, fundamental interactions to solid state and life sciences, 1300 isotopes of more than 70 elements have been used. Currently more than 450 researchers are active and associated with ISOLDE, working on about 90 experiments with about 50 experimental data taken every year. Thus the ISOLDE facility has gathered cutting-edge expertise in the field of research with radioactive beams.