Alexei Donyagin

Serial Magnetic Measurements for the NICA Quadruple Magnets of the NICA Booster Synchrotron

NICA is a new accelerator collider complex under construction at JINR, Dubna. More than 250 superconducting magnets are needed for the NICA booster and collider. The NICA Booster magnetic system includes 48 quadrupole superconducting magnets. The rotating coils probe developed for series magnetic measurements of booster quadrupoles doublets, as well as measuring methods are described. Results of magnetic measurements in cryogenic conditions for 12 doublets are presented and discussed. INTRODUCTION At the Laboratory of High Energy Physics (LHEP), serial assembly and testing of NICA Booster magnets were started at end of 2016 at the special facility [1]. The program of testing of magnets includes «warm» and «cold» magnetic measurements. It is necessary to assemble and test 48 quadrupole magnets for the NICA booster synchrotron. According to the specification, a magnetic measurement system, which is able to measure the effective length, magnetic field harmonics and magnetic axis in cold magnet inside the cryostat, is needed. QUADRUPLE MAGNET FOR THE NICA BOOSTER Figure 1: Booster doublet of quadrupole magnets. The Nuclotron-type design [2],[3] based on a cold iron yoke and a saddle shaped SC coil have been chosen for booster quadrupole magnets. The doublet consists of a focusing and a defocusing lattice quadrupole magnets, which are connected with each other in a single rigid mechanical construction of about 1.8 m length (see Fig.1). The main parameters of the quadrupole magnets are presented in Table 1. SPECIFICATION FOR MAGNETIC MEASUREMENTS According to the specification, following parameters of a quadrupole magnet have to be measured with the required tolerances: uf0a7 Relative standard deviation of effective lengths 4 5 10 eff eff eff L L L uf064 uf02d uf044 uf03d uf0a3 uf0d7 uf03c uf03e � = �2(�) ∞ −∞ � �2(0) uf0a7 The magnetic axis with respect to magnets fiducials. σ(Δx), σ (Δy) ≤ 0.1 mm uf0a7 Relative integrated harmonics 2 ∗ , 2 ∗ , 3 ∗ ≤5∙10

Measurement of the magnetic-field parameters of the NICA Booster dipole magnet

Serial assembly and tests of dipole and quadrupole magnets of the NICA Booster have started at the Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (JINR). The accelerator is fitted with Nuclotron-type magnets with a superconducting winding and an iron yoke for shaping the needed magnetic field. The design of magnets for NICA was optimized (based on the experience gained in constructing and operating the JINR Nuclotron) for the production of magnetic fields of the required configuration in terms of the beam dynamics in the accelerator and the collider. Measurements of parameters of the field of each magnet are expected to be performed in the process of assembly and testing of each module of the magnet-cryostat system of the NICA Booster and Collider. The results of magnetic measurements for the NICA Booster dipole magnet are presented.