Nuclotron

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Graphic representation of the NICA acceleration complex

The Nuclotron is a superconducting synchrotron - particle accelerator with 251.5 m circumference at the Joint Institute for Nuclear Research in Dubna ( Russia ).

history

In 1973 a first proposal for the construction of a superconducting 20  GeV synchrotron was made, the aim being to replace the synchrophasotron . In the following years, attempts were made with various superconducting magnets. For cost reasons, the magnets were designed for a maximum proton energy of only 6 GeV. The plan was approved in December 1986. A 1.5 GeV synchrotron with the name "SPIN" was built as a test facility for a synchrotron in the new design with superconducting magnets.

The Nuclotron was built between 1987 and 1992 in a tunnel 3.7 m below the synchrophasotron. The Nuclotron went into operation for the first time in March 1992, and the first physical experiments with a built-in target were carried out in 1994. A common pre-accelerator supplied the synchrophasotron and the nuclotron.

In 1999 the Nuclotron was expanded with a beam extraction unit, so that from March 2000 experiments outside the ring were possible.

Since 1996, plans to build a booster have been in progress to increase the beam intensity by a factor of 10–15.

The operation of the Nuclotron is mainly limited by financial constraints.

technology

Ions with atomic numbers 1 to 36, i.e. from hydrogen to krypton , have been accelerated in the nuclotron . The highest energy in the internal beam was 4.2 GeV per nucleon , in the deflected beam 2.2 GeV per nucleon. The cross section of the jet pipe is 110 × 55 mm.

The electromagnets of the Nuclotron have iron cores that are completely inside the cryostat . The coils consist of niobium - titanium wires. At the maximum flux density of the dipole magnets of 2  Tesla , a current of 6300 amperes flows through the magnets connected in series  . The inductance of the coils and thus the energy stored in the magnets is relatively low, which enables rapid changes in the magnetic field of up to 4 T / s. The relatively low field strength of the magnets made them easier to manufacture.

Only the nuclotron itself uses these superconducting magnets. The magnets on the beam guides to the experiment stations are normally conductive and require about half the energy requirements of the system. Therefore, there are considerations to replace these magnets with superconducting designs.

A cooling system with a closed helium circuit is used to cool the superconductors . However, larger quantities of liquid nitrogen are also required. At the start of operation, the Nuclotron could only be operated continuously as long as the liquid nitrogen supply was sufficient; between 12 and 15 tons of liquid nitrogen were used daily. It was only after the helium cooling systems had been converted that consumption could be reduced to such an extent that the institute's liquid nitrogen production capacities are sufficient for continuous operation. The cooling of the nuclotron to the temperature of 4.5 Kelvin required for the operation of the superconducting magnets  takes about 100 hours.

Web links

Commons : Nuclotron  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d A.D. Kovalenko: Nuclotron: First Beams and Experiments at the superconducting synchrotron in Dubna. Laboratory of High Energies, Joint Institute for Nuclear Research, 1994, accessed February 1, 2020 .
  2. ↑ IB Issinsky et al .: Beams of the Dubna Synchrophasotron and Nuclotron . In: Acta Physica Polonica B . 25, No. 3-4, 1994, pp. 673-680.
  3. ↑ a b A.D. Kovalenko, JINR, Dubna: Nuclotron: Status & Future ( English , PDF; 350 kB) Retrieved in 2000.
  4. ^ New prospects for the Dubna Nuclotron ( English ) Cerncourier. May 24, 2000. Retrieved December 22, 2009.
  5. ↑ a b c d e N.N. Agapov et al .: Status of the Nuclotron, Main Results and Perspectives ( English ) JINR, Dubna. Retrieved December 22, 2009.
  6. ↑ V. Anguelov, D. Dinev: Simulation of the multi-turn Injection Into Nuclotron booster . In: Bulgarian Journal of Physics . 23, No. 3-4, March 7, 1996, pp. 97-103. Accessed February 1, 2020.
  7. ↑ NN Agapov et al .: Rapid Cycling Superconducting Booster Synchrotron . In: Bulgarian Journal of Physics . 28, No. 3-4, 2001, pp. 112-119.