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Critical analysis of industrial electron accelerators
ARTICLE IN PRESS
Radiation Physics and Chemistry 71 (2004) 535–537
Business paper
Critical analysis of industrial electron accelerators S. Korenev* STERIS Corporation, STERIS Isomedix Services, 2500 Commerce Drive, Libertyville, IL 60048, USA
Abstract The critical analysis of electron linacs for industrial applications (degradation of PTFE, curing of composites, modification of materials, sterlization and others) is considered in this report. Main physical requirements for industrial electron accelerators consist in the variations of beam parameters, such as kinetic energy and beam power. Questions for regulation of these beam parameters are considered. The level of absorbed dose in the irradiated product and throughput determines the main parameters of electron accelerator. The type of ideal electron linac for industrial applications is discussed. r 2004 Elsevier Ltd. All rights reserved. Keywords: Electron; Beam; Accelerator; X-ray target
1. Introduction The electron industrial accelerators on the basis of linacs found wide industrial and medical applications (Shiriava and Kozlov, 1980; Wood and Pikaev, 1994). The electron industrial accelerators, on the basis of linacs, consist of an electron injector with electron gun, a linear accelerating structure, a power supply system for accelerating structure, a scanning electron beam system, and a system for output electron beam from vacuum chamber to air or chamber for irradiation, vacuum and control systems (Wamgler, 1988; Deruyter et al., 1999; Auslender et al., 2002). The status of electron linacs in the industrial applications is very complex. It links with different designs of accelerators and their applications (Korenev, 2000). The critical analysis of industrial electron linacs and attempt for formulation of task directed to manufacturing companies is considered in this paper.
2. Main requirements to electron accelerators for industrial applications The main requirements to accelerators for industrial applications are the following: *
*
*
*
*
* *
* *
*Tel.: +1-847-573-3223; fax: +1-847-247-0882. E-mail address: sergey [email protected] (S. Korenev). 0969-806X/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.radphyschem.2004.03.055
the variation of beam power for regulation of absorbed dose in the irradiated product; the regulation of kinetic energy of electrons for variation of thickness for irradiated product; the forming of scanning electron beam with parallel trajectories after foil window for increasing of beam efficiency; on-line or real-time diagnostic systems for measurements of parameters of electron beam and absorbed dose in the irradiated product for increasing of reliability of equipment and efficiency of radiation processes; the long lifetime for cathode of electron gun in the injector and foil window for output electron beam; reliable and low cost of accelerator; more universal for different radiation technologies with different materials; simple, cheaper and effective radiation shield; simple design of electron accelerator for including to the system of irradiation lines for radiation technologies.
ARTICLE IN PRESS 536
S. Korenev / Radiation Physics and Chemistry 71 (2004) 535–537
This system of irradiation lines must include the next main components:
4. X-ray sources on the basis of electron accelerators
1. irradiator on the basis of electron accelerator or Xray source; 2. system for radiation safety; 3. irradiation area or chamber; 4. system for delivery of product to irradiation area or chamber; 5. system for control of absorbed dose in irradiated product.
The low factor of conversion of electrons to X-rays in the electron beam-irradiated target leads to increasing of power electron accelerator. The average power of linacs for X-ray source is about 50–100 kW. Dynamitron (Cleland, 1991) and Rhodotron (Pottier, 1989) can provide much bigger beam power. The pulsed high current linear induction accelerators can be considered in the future for generation of X-rays for industrial applications.
The main two important requirements have principal meaning for industrial accelerators:
5. The ideal electron linac for industrial applications
a. regulation of kinetic energy of electrons; b. regulation of power beam. The problem of variation for kinetic energy by electrons consists in the regulation for parameters of electrical fields in accelerating structures. It is a difficult technical and engineering task. The effect of simultaneous variation for RF electrical field phase and RF power in every cavity of accelerating structure can be used for regulation of kinetic energy by electrons and beam power (Bogdanovich et al., 2001). The regulation of power by variation of beam current also is possible.
3. Main problems of using of electron linacs Main problems of electron linacs are the following: *
*
* *
* * *
*
the limitation on the thickness of irradiated product, especially with high density; the different level of absorbed dose for various radiation technologies; problems for regulation of electron beam parameters; 30–60% use of electron beam power in the irradiated product; the lifetime of cathode by electron gun; the lifetime of foil window; the control for electron beam parameters in the irradiated product; the high concentration of ozone in the irradiated area.
Analysis of beam power losses shows next three main factors: *
* *
the distribution of absorbed dose in the irradiated product on the level of 720% regarding average dose; an angle scanning of electron beam; the factor of using of conveyor line.
The ideal electron linac must have regulations for kinetic energy and power of electron beam. Linac can be included into the system for irradiation of product. Two variants of ideal accelerators for industrial applications that can be considered are: *
*
the single electron linear accelerator with high power and full variation of kinetic energy of electrons, and beam power; the separated electron linear accelerators with few levels of kinetic energy of electrons with required variable beam power.
The few levels of kinetic energy that can be considered for linacs are: (a) 0.25–3.0 MeV; (b) 3.0–7.0 MeV; (c) 7.0–10.0 MeV.
6. Conclusion As a result of this critical analysis of electron linacs for industrial applications in the wide aspect for different radiation technologies with required doses from 1 to 2000 kGy in the irradiated product, we can make the following conclusions: *
*
at present, the universal industrial electron accelerator is absent in the manufacturing aspect; this paper is an attempt to formulate the task for design of universal electron accelerator for industrial applications.
Acknowledgements I would like to thank John Masefield, Nikolai Mokhov and Andrey Mishin for useful discussions and information regarding industrial electron accelerators.
ARTICLE IN PRESS S. Korenev / Radiation Physics and Chemistry 71 (2004) 535–537
References Auslender, V.L., Bryazdin, A.A., Fatkorovich, B.L., Gorbunov, V.A., Kokin, E.N., Korobeinikov, M.V., Krainov, G.S., Lukin, A.N., Maximov, S.A., Nekhaev, V.E., Panfilov, A.D., Radchenko, V.N., Tkachenko, V.O., Tuvik, A.A., Voronin, L.A., 2002. Accelerators for E-beam and X-ray processing. Radiat. Phys. Chem. 63 (3–6), 613–615. Bogdanovich, B.Yu., Kaminsky, V.I., Nesterovoch, A.V., Masunov, E.S., Korenev, S.A., 2001. Concept of electron linac with regulation of main parameters for radiation technologies. In: Proceedings of the 2001 Particle Accelerator Conference, 2001, Vol. 4, pp. 2530–2532. Cleland, M.R., 1991. High power electron accelerators for industrial radiation processing. In: Singh, A., Silverman, J. (Eds.), Radiation Processing of Polymers. Oxford University Press, Oxford, New York, pp. 23–49.
537
Deruyter, H., Foose, R., Mishin, A.V., Sapp, W., Schonberg, R.G., Skowbo, D., 1999. Portable CW linac for commercial applications. In: Proceedings of the 1999 Particle Accelerator Conference, Vol. 1, pp. 590–591. Korenev, S.A., 2000. Critical analysis of industrial electron linacs. In: Proceedings of XX International Linac Conference, pp. 645–647. Pottier, J., 1989. A new type of RF electron accelerator: The Rhodotron. Nucl. Instrum. Methods B 40/41, 941–945. Shiriava, G.V., Kozlov, Yu.D., 1980. Technology of Radiation Curing of Coatings. Atomizdat, Moscow. Wamgler, T., 1988. RF Linear Accelerators. Wiley Series in Beam Physics and Accelerator Technology, New York. Wood, R.J., Pikaev, A.K., 1994. Applied Radiation Chemistry: Radiation processing. A Wiley-Interscience Publication, Wiley, New York.
Radiation Physics and Chemistry 71 (2004) 535–537
Business paper
Critical analysis of industrial electron accelerators S. Korenev* STERIS Corporation, STERIS Isomedix Services, 2500 Commerce Drive, Libertyville, IL 60048, USA
Abstract The critical analysis of electron linacs for industrial applications (degradation of PTFE, curing of composites, modification of materials, sterlization and others) is considered in this report. Main physical requirements for industrial electron accelerators consist in the variations of beam parameters, such as kinetic energy and beam power. Questions for regulation of these beam parameters are considered. The level of absorbed dose in the irradiated product and throughput determines the main parameters of electron accelerator. The type of ideal electron linac for industrial applications is discussed. r 2004 Elsevier Ltd. All rights reserved. Keywords: Electron; Beam; Accelerator; X-ray target
1. Introduction The electron industrial accelerators on the basis of linacs found wide industrial and medical applications (Shiriava and Kozlov, 1980; Wood and Pikaev, 1994). The electron industrial accelerators, on the basis of linacs, consist of an electron injector with electron gun, a linear accelerating structure, a power supply system for accelerating structure, a scanning electron beam system, and a system for output electron beam from vacuum chamber to air or chamber for irradiation, vacuum and control systems (Wamgler, 1988; Deruyter et al., 1999; Auslender et al., 2002). The status of electron linacs in the industrial applications is very complex. It links with different designs of accelerators and their applications (Korenev, 2000). The critical analysis of industrial electron linacs and attempt for formulation of task directed to manufacturing companies is considered in this paper.
2. Main requirements to electron accelerators for industrial applications The main requirements to accelerators for industrial applications are the following: *
*
*
*
*
* *
* *
*Tel.: +1-847-573-3223; fax: +1-847-247-0882. E-mail address: sergey [email protected] (S. Korenev). 0969-806X/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.radphyschem.2004.03.055
the variation of beam power for regulation of absorbed dose in the irradiated product; the regulation of kinetic energy of electrons for variation of thickness for irradiated product; the forming of scanning electron beam with parallel trajectories after foil window for increasing of beam efficiency; on-line or real-time diagnostic systems for measurements of parameters of electron beam and absorbed dose in the irradiated product for increasing of reliability of equipment and efficiency of radiation processes; the long lifetime for cathode of electron gun in the injector and foil window for output electron beam; reliable and low cost of accelerator; more universal for different radiation technologies with different materials; simple, cheaper and effective radiation shield; simple design of electron accelerator for including to the system of irradiation lines for radiation technologies.
ARTICLE IN PRESS 536
S. Korenev / Radiation Physics and Chemistry 71 (2004) 535–537
This system of irradiation lines must include the next main components:
4. X-ray sources on the basis of electron accelerators
1. irradiator on the basis of electron accelerator or Xray source; 2. system for radiation safety; 3. irradiation area or chamber; 4. system for delivery of product to irradiation area or chamber; 5. system for control of absorbed dose in irradiated product.
The low factor of conversion of electrons to X-rays in the electron beam-irradiated target leads to increasing of power electron accelerator. The average power of linacs for X-ray source is about 50–100 kW. Dynamitron (Cleland, 1991) and Rhodotron (Pottier, 1989) can provide much bigger beam power. The pulsed high current linear induction accelerators can be considered in the future for generation of X-rays for industrial applications.
The main two important requirements have principal meaning for industrial accelerators:
5. The ideal electron linac for industrial applications
a. regulation of kinetic energy of electrons; b. regulation of power beam. The problem of variation for kinetic energy by electrons consists in the regulation for parameters of electrical fields in accelerating structures. It is a difficult technical and engineering task. The effect of simultaneous variation for RF electrical field phase and RF power in every cavity of accelerating structure can be used for regulation of kinetic energy by electrons and beam power (Bogdanovich et al., 2001). The regulation of power by variation of beam current also is possible.
3. Main problems of using of electron linacs Main problems of electron linacs are the following: *
*
* *
* * *
*
the limitation on the thickness of irradiated product, especially with high density; the different level of absorbed dose for various radiation technologies; problems for regulation of electron beam parameters; 30–60% use of electron beam power in the irradiated product; the lifetime of cathode by electron gun; the lifetime of foil window; the control for electron beam parameters in the irradiated product; the high concentration of ozone in the irradiated area.
Analysis of beam power losses shows next three main factors: *
* *
the distribution of absorbed dose in the irradiated product on the level of 720% regarding average dose; an angle scanning of electron beam; the factor of using of conveyor line.
The ideal electron linac must have regulations for kinetic energy and power of electron beam. Linac can be included into the system for irradiation of product. Two variants of ideal accelerators for industrial applications that can be considered are: *
*
the single electron linear accelerator with high power and full variation of kinetic energy of electrons, and beam power; the separated electron linear accelerators with few levels of kinetic energy of electrons with required variable beam power.
The few levels of kinetic energy that can be considered for linacs are: (a) 0.25–3.0 MeV; (b) 3.0–7.0 MeV; (c) 7.0–10.0 MeV.
6. Conclusion As a result of this critical analysis of electron linacs for industrial applications in the wide aspect for different radiation technologies with required doses from 1 to 2000 kGy in the irradiated product, we can make the following conclusions: *
*
at present, the universal industrial electron accelerator is absent in the manufacturing aspect; this paper is an attempt to formulate the task for design of universal electron accelerator for industrial applications.
Acknowledgements I would like to thank John Masefield, Nikolai Mokhov and Andrey Mishin for useful discussions and information regarding industrial electron accelerators.
ARTICLE IN PRESS S. Korenev / Radiation Physics and Chemistry 71 (2004) 535–537
References Auslender, V.L., Bryazdin, A.A., Fatkorovich, B.L., Gorbunov, V.A., Kokin, E.N., Korobeinikov, M.V., Krainov, G.S., Lukin, A.N., Maximov, S.A., Nekhaev, V.E., Panfilov, A.D., Radchenko, V.N., Tkachenko, V.O., Tuvik, A.A., Voronin, L.A., 2002. Accelerators for E-beam and X-ray processing. Radiat. Phys. Chem. 63 (3–6), 613–615. Bogdanovich, B.Yu., Kaminsky, V.I., Nesterovoch, A.V., Masunov, E.S., Korenev, S.A., 2001. Concept of electron linac with regulation of main parameters for radiation technologies. In: Proceedings of the 2001 Particle Accelerator Conference, 2001, Vol. 4, pp. 2530–2532. Cleland, M.R., 1991. High power electron accelerators for industrial radiation processing. In: Singh, A., Silverman, J. (Eds.), Radiation Processing of Polymers. Oxford University Press, Oxford, New York, pp. 23–49.
537
Deruyter, H., Foose, R., Mishin, A.V., Sapp, W., Schonberg, R.G., Skowbo, D., 1999. Portable CW linac for commercial applications. In: Proceedings of the 1999 Particle Accelerator Conference, Vol. 1, pp. 590–591. Korenev, S.A., 2000. Critical analysis of industrial electron linacs. In: Proceedings of XX International Linac Conference, pp. 645–647. Pottier, J., 1989. A new type of RF electron accelerator: The Rhodotron. Nucl. Instrum. Methods B 40/41, 941–945. Shiriava, G.V., Kozlov, Yu.D., 1980. Technology of Radiation Curing of Coatings. Atomizdat, Moscow. Wamgler, T., 1988. RF Linear Accelerators. Wiley Series in Beam Physics and Accelerator Technology, New York. Wood, R.J., Pikaev, A.K., 1994. Applied Radiation Chemistry: Radiation processing. A Wiley-Interscience Publication, Wiley, New York.