Measurements and Corrections of the Lorentz Factor of Transition Energy of the CSRe Storage Ring in the Isochronous Mode

The latest developments of measurements and corrections of the transition energy of the cooling storage ring CSRe at the Lanzhou are reviewed in this paper. The principle of the method used to measure the transition energy of the storage ring CSRe is introduced. This method was used to investigate the influence of dipole magnetic fields, quadrupole magnetic fields and sextupole magnetic fields on the transition energy curve. Experimental results show that the transition energy curve can be horizontally, vertically shifted as well as rotated, by varying dipole magnetic fields, quadrupole magnetic fields and sextupole magnetic fields, respectively. With the corrections of the quadrupole magnets and sextupole magnets at the CSRe, the mass resolving power R for the target nuclei was improved from R=3.15(9)×10⁴ (relative error of revolution time σT/T=7.3(2)×10^-6) to 1.72(4)×10⁵ (σT/T=1.34(3)×10^-6).