No abstract available

No abstract available

[en] A nuclear magnetometer designed for the JINR synchrocyclotron is described. NMR on proton is used in the magnetometer and rubber is used as a proton-containing substance. The magnetometer sensor is in the accelerator room, and the remaining part (the indication module) is in the control room. The magnetometer has operated in the synchrocyclotron for 6 years without repairs. 3 refs.; 1 fig

No abstract available

[en] The main magnetic field characteristics of the JINR phasotron (''F'' unit), intended for the proton acceleration up to 680 MeV with 10 μA intensity are considered. To increase the magnetic field medium radial component admissible values Bsub(r) in the phasotron central region a new medium vertical component change low is suggested: in <= r <= 18 sm radius area the field decreases by 3 mT and then it starts increasing (the variant of the field with the bump). This allows to increase theasmissible value Bsub(r) from 0.2-0.3 mT up to 0.5-0.7 mT. The medium magnetic field ''bump variant'' provides for a stronger charged particle vertical focusing, which allows to accelerate the proton beam at Bsub(r) <= 0.6 mT in the central region. In this case the medium magnetic field, the fourth harmonic amplitude and phase provide for the vertical and radial charged particle motion stability in the whole of the working radiusarea. To improve the radial beam quality by shimming the first harmonic amplitude in the accelerator working radius region r <= 50 sm is brought up to 0.2-0.3 mT. For the other radii the first harmoic amplitude does not exceed 1 mT

[en] Short communication

[en] The magnetic field calculation of the magnet system model of the phasotron with the space variation of magnetic field with proton energy of 680 MeV by means of the POISSON program is given. On the base of comparing the results of calculation with experiment it is shown that the accuracy of average magnetic field calculation for various configurations of the magnet system is about 5 percent. The calculations of different shimming elements influence have been performed with the accuracy better than 10 percent. The magnetic field contribution for the trim coils has been found with the accuracy of 5 percent and the influence of the changes in the construction of the phasotrons magnet system have been calculated. The forces acting on various elements of the magnet system have been calculated. The calculations show the effectivity of using POISSON program for complicated magnetic systems with spiral and ring shimmes during their construction and during shimming of the magnetic field. This gives a considerable decreasing of the experimental work

[en] An accelerated beam in the JINR phasotron has a pulsed time structure. To improve the beam time structure, beam stretching is used by postaccelerating the beam with a C-electrode. The beam postacceleration is provided by the method of synchrocyclotron acceleration. This is the first time when phase displacement is used for the beam stretching in a phasotron. The experimental results are evaluated. (R.P.) 4 refs.; 5 figs

[en] The proton beam regenerative extraction from the JINR Phasotron is examined with the specially prepared computer code for beam dynamic simulation. The beam extraction efficiency in the preliminary calculations was found to be more than 40%

[en] A direct-current stabilizer is proposed. Its measuring part is based on a magnetic modulation device for comparison of constant voltages, a standard measuring manganin shunt with voltage drop rating 75 mV, a source of reference current and a reference resistor. The structure scheme of the stabilizer and its principle of operation are discussed, basic information on the design of a model of the measuring part of the stabilizer for current rating 600 A is given. The model test showed that the relative current instability did not exceed 10^-3 in 8 hours. 5 refs.; 4 figs