Dark currents of a tandem accelerator with vacuum insulation

Accelerator based epithermal neutron source

“…The characteristic time of gas outflow is 500 s. Stripping of the negative hydrogen ions into the protons is studied experimentally by measuring the beam current at the exit of the accelerator when changing gas injection rate into the target. A good agreement between the experimental and calculated data was found [79,80]. A method of calibrating the stripping gas target is proposed and implemented, based on the measurement of gas inflow at which the proton current is equal to the current of non recharged negative hydrogen ions at the exit of the accelerator.…”

“…As a result of the training of all gaps using a specially made device, the required volt age of the accelerator (1 MV) was obtained [72]. The behavior of the dark current was studied and its reduc tion to an acceptable level by means of long exposure under the voltage was carried out [73]. Detailed results of the study of the high voltage strength of tandem accelerator with vacuum insulation are presented in the thesis by Sorokin [74].…”

Proton beam of 2 MeV 1.6 mA on a tandem accelerator with vacuum insulation

“…The way of consistent training of accelerating gaps proposed and realized and the required voltage of 1 MV was obtained [10]. The behaviour of dark currents was studied and then they were reduced to an acceptable level by long staying under voltage [11]. An auto-emission current was detected, the cause of its occurrence was established, and changes in the design of the accelerator to prevent it were made [11].…”

“…The behaviour of dark currents was studied and then they were reduced to an acceptable level by long staying under voltage [11]. An auto-emission current was detected, the cause of its occurrence was established, and changes in the design of the accelerator to prevent it were made [11]. The reason for the reduction of the first electrode potential was fixed.…”

Suppression of an unwanted flow of charged particles in a tandem accelerator with vacuum insulation

“…The accelerator is characterized by fast ion acceleration (25 kV/cm) and a large distance between the ion beam and the insulator (on which electrodes are mounted). After the dark current was decreased to an acceptable level [3], the injection of a negative hydrogen ion beam into the accelerator [4] and stripping in the gas stripping target was optimized [5], the proton beam current was increased from the initial values of about 140 µA [6] to 1.6 mA [7], which was stable for more than one hour. In the elucidation of the reasons for the limitation of the current in the tube for accelerating negative hydrogen ions, a significant electron flow and a counter-flow of positive ions generated in the acceleration tube and in the stripping target were found and measured [8].…”