Improvement of the proton irradiation methodology for radiation-chemical studies
Abstract Generated abstract
A modified proton irradiation method for radiation-chemical studies is described to address post-irradiation annealing during experiments on ionic salts at elevated temperatures. The authors developed a remotely controlled heated irradiation cell for use with an extracted cyclotron proton beam, incorporating temperature regulation, thermocouple recording, and a solenoid mechanism that opens the cell immediately after irradiation. This design ejects the heated tablet sample directly into a solvent, enabling rapid cooling and dissolution to suppress annealing effects. The system was implemented on the cyclotron facility of the Research Institute of Nuclear Physics for irradiations over the temperature range 25 to 300°C.
Full Text
IMPROVEMENT OF THE PROTON IRRADIATION METHODOLOGY IN RADIATION-CHEMICAL STUDIES
L. P. Eremin, A. N. Oblivantsev
(Presented by the scientific seminar of the “Cyclotron” facility of the Research Institute of Nuclear Physics, Electronics, and Automation)
We previously described [1, 2] a method of irradiation on a cyclotron with an extracted proton beam, which was used in studies of the radiation destruction of ionic salts at room temperatures. The need to study these processes at elevated temperatures required improvement of the irradiation method that had been used, since it does not eliminate post-radiation annealing, which at elevated temperatures proceeds very intensively for a number of compounds [2, 3].
In this connection, a remotely controlled device was constructed that makes it possible, immediately after completion of the irradiation process, to eject the heated sample into a solvent, where it is rapidly cooled and dissolved, thereby preventing annealing. The device and control circuit are shown in Fig. 1.
The irradiation cell 3, made of aluminum, is mounted in a textolite housing 9 on axle 8. In the center of the cell a recess 0.5 mm deep and 16 mm in diameter is milled out for placing the tableted sample 4, which is covered with aluminum foil 7 of thickness 2 mg/cm². The latter is pressed against the housing by cover 1, which has an opening for the passage of proton beam 5.
The sample is placed in the recess when the cell is set in the horizontal position, and the housing with the cover is raised at an angle to the cell, which is achieved by rotating it about axle 8; after this the cover is closed and the device is mounted vertically on the flange of the ion guide, so that the cover lies tightly against the outlet foil of the flange.
The conical cup 20 with solvent is installed in ring 18 when the latter is turned about axle 19 and is held between two posts 17 attached to housing 9.
Immediately after irradiation is completed, pressing button KN supplies current to the winding of solenoid 12, as a result of which core 13 is drawn into the coil and, through rod 14, turns lever 15 about axle 8, opening the cell. The tablet falls into the cup.
The solenoid is attached to the device housing by means of plate 10. Heating of the cell is carried out by special bifilarly wound nichrome elements 2 in porcelain thermocouple tubes. The heat-insulating screen 16 with textolite lever 15 prevents excessive heating of the solenoid.
The temperature is measured by a chromel-copel thermocouple 6, located—
…located near the sample and is recorded on an EPP-09 recorder.
Coarse setting of the temperature is achieved by taking the required voltage from the LATR autotransformer, and regulation is carried out by a system of MKU-48 and RES-10 relays. The use of two relays is due to the fact that one of the contacts of the winding of the primary relay is set on the indicating scale of the instrument and through it is connected to the housing of the latter. The other contact is insulated and fastened to the indicating flag of the recording device and moves with it. To maintain the required temperature, the contact on the scale is set to the corresponding reading.
Fig. 1. Device and remote-control circuit for proton irradiation on a cyclotron
For powering the primary relay, one of the windings of the recorder transformer is used. To signal that the heater has been switched on, the signal lamp of the recorder is used; its circuit is connected through the contacts of the secondary relay.
The control system is located outside the experimental hall and is connected to the device by a cable through connector 11.
The system described is used for proton irradiation on the cyclotron of the Scientific Research Institute of Nuclear Physics in the temperature range 25–300°C.
REFERENCES
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A. N. Oblivantsev, L. P. Eremin, V. M. Lykhin. Theoretical and Experimental Chemistry, 3, 844, 1967.
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A. N. Oblivantsev, V. V. Boldyrev, L. P. Eremin, V. M. Lykhin. Kinetics and Catalysis, 7, 1015, 1966.
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V. M. Lykhin, V. V. Boldyrev. High Energy Chemistry, 1, 260, 1967.