MSP-144 magnetic analyser is intended for separation of elastically scattered ion beams, reaction products efficient accumulation and distribution in compliance with A mass dispersion and q charge with appropriate resolution (Δp/p).
MSP-144 magnetic analyser
Fig.1 Principal circuit of ion-beam line with MSP-144 magnetic analyser
Magnetic field introduction is a very important stage in creation of the detecting system for reaction product analysis. This system consists of a magnetic analyser and a detector at analyser's focal plane. Reaction products and elastically scattered ions separate spatially thanks to their
difference in magnetic rigidity. By magnetic field fitting one may make elastically scattered ions pass by detector which allows to use ion beams of maximum intensity and measure at lesser angle. Due to magnetic-field focusing effect the considerably greater solid angles may be used in the magnetic analyser than in direct vision detectors.
Fig.2 Scheme of the FLNR MSP-144 wide-range magnetic analyser with stepped poles
The focal plane detector consists of a four-section ionisation chamber and two position-sensitive proportional counters. Fig.3 shows the ionisation chamber cross-section.
Fig.3 Ionisation chamber cross-section (A.V.Belozerov et al., JINR Preprint, P15-89-225)
The detector was designed to meet the following requirements: the detector should accurately identify nuclear reaction products by charge up to Z/ΔZ=20 and by mass up to А/ΔА=40. To this end both loss of power and particle residual energy should be measured in a wide range to within several percents.
Ionisation chamber anode consits of four components: two ΔE-electrodes (to measure particle ionisation loss), ER-electrode (to measure particle residual residual energy) and "VETO"-electrode (to register long-range particles). More exactly product energy may be determined by a coordinate measured at the spectrometer focal plane by the position-sensitive detectors and by spectrometer magnetic field value. Besides two position-sensitive counters provide data on the particle path.
The possibility to widely vary the reaction product registration angle is one of the advantages of this analyser. Faraday cup monitors the beam.