Ion Collider fAcility


The Collider will be constructed in a tunnel with additional buildings for two detectors and the electron cooler.

Collider will be operated at a fixed energy without acceleration of an injected beam. To provide required linearity of the field the maximum bending field is chosen to be of 1.8 T.

Two collider rings are placed one above the other and the beam superposition/separation is provided in the vertical plane. The distance between the ring median planes is chosen to be 32 cm. That is achieved with dipole and quadrupole magnets having two apertures in one yoke.

The ring has a racetrack shape with two arcs and two long straight sections. The minimum beta function in the interaction point is 35 cm. The ring acceptance is limited by aperture of the final focus lenses is not less than 40 π ⋅ mm ⋅ mrad. Rms bunch length in the collision mode is 60 cm. The inter-bunch distance is larger than 21 m.

The arc optic structure consisting of 12 regular cells of FODO type.

Scheme of the FODO periodic cell: QF, QD – focusing and defocusing quadrupoles, Dip – dipole magnets, PU – pick-up station, Corr – corrector pack.

Scheme of the collider ring with equipment and insertions.

To provide the beam storage and bunch formation in the collider 3 independent RF systems are used (see table “Main parameters of the collider RF system”):
1. RF barrier bucket system (RF1) at 5 kV of the voltage amplitude, allowing storage of the required beam intensity,
2. 1st narrow-band RF system (RF2) operating at harmonics of revolution frequency corresponding to the bunch number; it provides the beam bunching and the bunch compression. Maximum voltage amplitude for this system is 100 kV.
3. 2nd narrow-band RF system (RF3) operating at harmonics number three times larger than the 1st one, that provides the bunch length necessary for collision experiments. Maximum voltage amplitude for this system is 1 MV.
Collider injection system consists of septum (MS) and kicker (K) which are placed in the “missing” dipole cell of the bending arc. The emittance of the injecting beam from Nuclotron is εx,y = 1.2 π ⋅ mm ⋅ mrad.

For luminosity preservation in the heavy ion collision mode, electron (ECool) and stochastic cooling systems (PU-X, PU-Y, PU-L are the horizontal, vertical and longitudinal pick-ups, K-X, K-Y, K-L – corresponding kickers) are used. The electron cooling system will be used in the ion energy range from 1 to 3 GeV/u, the stochastic cooling – from 3 to 4.5 GeV/u. The band of the stochastic cooling system is from 2 to 4 GHz. The longitudinal degree of freedom will be cooled using Palmer method.