- Email: [email protected]
High energy heavy ion microbeam irradiation facility at IMP
Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb
High energy heavy ion microbeam irradiation facility at IMP Lina Sheng ⇑, Mingtao Song, Xiaoqi Zhang, Xiaotian Yang, Daqing Gao, Yuan He, Bin Zhang, Jie Liu, Youmei Sun, Bingrong Dang, Wenjian Li, Hong Su, Kaidi Man, Yizhen Guo, Zhiguang Wang, Guoqing Xiao Institute of Modern Physics, Chinese Academy of Sciences, P.O. Box 31, 509 Nanchang Rd., Lanzhou 730000, China
a r t i c l e
i n f o
Article history: Available online 1 March 2011 Keywords: Heavy ion High energy Microbeam Quadrupole lens
a b s t r a c t A high energy heavy ion microbeam irradiation facility was designed and installed in the Institute of Modern Physics (IMP) of Chinese Academy of Sciences (CAS). It can deliver well-focused ions into the targets at exact locations. With the advantage of allowing vertical irradiation as well as focusing ions from Carbon to Uranium with high energies in a broad energy range (7 MeV/u to 100 MeV/u for Carbon ions), this setup is able to deliver a preset number of ions into pre-selected target positions. Material specimens in vacuum and living cells in air can also be irradiated by this facility. Detailed description of this microbeam facility as well as its beam optics is presented in this paper. Some preliminary test results are also given. Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction Comparing to the broad beam, a microbeam has many advantages such as the ability to irradiate the targets on the micron scale, which makes it widely applicable in material science, biology, biomedicine, micromachining and so on. Up to date, various microbeam facilities have been developed or are under development in the world [1–6]. For example, heavy ions with a maximum energy of 27.5 MeV/u can be provided at the microbeam facility in JAEA Takasaki (TIARA). The recent development of astronautics indicates that the microbeam using high atomic number and high energy (HZE) ions can be more effective to study the so called late effect in astronauts, as well as the single event phenomena in semiconductor devices for space crafts for the irradiation characteristics in space [7–12]. Therefore, it is preferable to build a microbeam with HZE. In the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) a microbeam facility was designed and installed, in which the maximum energy is designed to be up to 100 MeV/u for Carbon ions and the target is designed to be irradiated both in vacuum and in air. Therefore, this microbeam facility will make a significant impact on many scientific research fields mentioned above in the near future. 2. IMP microbeam facility and beam optics 2.1. Microbeam line The IMP microbeam line was built at the Heavy Ion Research Facility in Lanzhou (HIRFL), in which a variety of ions from Carbon ⇑ Corresponding author. Tel.: +86 18919199596. E-mail address: [email protected] (L. Sheng). 0168-583X/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2011.02.075
to Uranium can be supplied. The ions, produced in the electron cyclotron resonance ion source (ECRIS), are accelerated up to 100 MeV/u for Carbon ions in a cascade operation of cyclotrons, SFC and SSC, and then delivered into the microbeam line. The microbeam line is settled at the basement. Fig. 1 shows the layout of the IMP microbeam line. At first, the ions are focused by a quadrupole triplet (R0Q1-R0Q3) onto an object slit. The object slit with adjustable range from 0 to 150 lm, manufactured by Technisches Büro S. Fischer, is installed before two 45 degree dipole magnets (R0B1-R0B2). The two dipoles and a quadrupole (R0Q4) in between form a symmetric achromatic configuration, which transfer the ions into the microbeam line in the basement. Using the two 45 degree dipole magnets as an energy analyzer, the momentum spread of the ions is determined by the momentum spread defining slit just after R0Q4. The divergence angle of the ion beam is defined using a divergence angle defining slit in combination with the object slit. This slit is similar to the object slit but with an adjustable range from 0 to 1500 lm. A beam switch is set right after the divergence angle defining slit, which consists of two parallel electrodes connected to a high-voltage generator. It is used to switch the beam on and off in order to control that the preset number of ions irradiates the target. The ions can be positioned to the defined target area for spot irradiation, using X and Y scanning magnets. As a final adjustment, a high gradient quadrupole triplet (R0Q5-R0Q7) with a bore diameter of 15 mm is used to focus the ions down to the micron scale. An anti-scattering slit is located directly in front of this high gradient quadrupole triplet to prevent the scattered ions from entering into the quadrupole lenses. All the components are mounted on a heavy rigid support with vibration isolation.
2190
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
Fig. 1. Layout of the IMP microbeam line.
Fig. 2. Details of the IMP microbeam facility.
Fig. 3. Beam envelope of the IMP microbeam line in vacuum calculated by the TRACE-3D code (D denotes drift space, E denotes hard edge fringe field, B denotes dipole magnet, Q denotes quadrupole lens; the numbers in this figure denote the number of the element).
2.2. Experiment platform This facility serves to irradiate both material specimens in vacuum and living cells in air. The vacuum chamber is designed for material irradiation in vacuum, including an optical microscope, a 3-axis sample stage, and a channeltron. The channeltron is used to collect secondary electrons, which enables to count single ion. By contrast, the living cells need to be irradiated in solution or in a humidified atmosphere and at normal air pressure. The inverted
Table 1 Beam optics parameters in vacuum calculated by the TRANSPORT code. Demagnification Chromatic aberration coefficients Spherical aberration coefficients
15.2 15.2 329.7 lm/(mrad%) 182.0 lm/(mrad%) 175.1 lm/mrad3 166.0 lm/mrad3 33.71 lm/mrad3 165.9 lm/mrad3
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
2191
Fig. 4. Beam spot for successive three seconds monitored on the microscope with 4 objective.
fluorescence microscope is the main instrument for living cells experiments and is installed in air below the vacuum chamber. The ions are delivered through a Si3N4 vacuum window with a thickness of 200 nm to the air safely. Furthermore, the window is used as an electron emitter for the channeltron. Fig. 2 shows the details of the IMP microbeam facility. 2.3. Beam optics The beam optics was simulated by the TRANSPORT, TRACE-3D [13], MIRKO [14] and Zgoubi [15] codes for the IMP microbeam line, which has a non-straight configuration. Fig. 3 shows the beam envelope of the IMP microbeam line in vacuum calculated by the TRACE-3D code. This microbeam system has two foci: one in vacuum and the other in air. For this, the working distances are 410 mm and 510 mm, respectively. In this paper, the beam optics parameters, calculated by the TRANSPORT code, are given for the transport line in vacuum (Table 1). These parameters are obtained after the optimization of the final beam spot sizes 1 lm in vacuum and 2 lm in air. The following conditions are required: the object sizes are both 7 lm, the divergence angles are both 0.05 mrad, the momentum spread is 0.01%. 3. Recent test results After the commissioning in 2009, many measurements have been made for testing the performance of the microbeam line. A beam monitor device developed in IMP, combining a CaF2(Eu) scin-
tillator and the inverted fluorescence microscope, is used to monitor the beam spot in air, although its resolution is about 2 lm with 4 objective. Fig. 4 shows a 12 lm beam spot for 40Ar15+ with an energy of 25 MeV/u extracted from the beam monitor device. In order to get a higher detection precision, a Cu grid with a bar width of 9 lm and a hole width of 16 lm is placed in the target plane in air to measure the transmitted energy of the ions using a silicon particle detector behind the Cu grid. The precision for this detector is high enough to monitor 1 lm beam spot. In addition, a polycarbonate (PC) track-etch plastic is used to verify the precise beam spot size. It has a high precision but with a long time for etching. Fig. 5 shows a 38 lm beam spot size in air from irradiated PC track-etch plastic for 40Ar15+ ions with an energy of 25 MeV/u. For the ion detection, the scintillator film BC400 was used at the target position in combination with a photodiode placed at one of the objectives of the inverted fluorescence microscope. In future, the secondary electron detector, which is under test now, will provide information about the number of ions delivered at the target. 4. Conclusion and outlook A well-focused high energy heavy ion microbeam irradiation facility has been constructed in IMP, CAS. The details of the IMP microbeam facility are presented with the beam optics parameters and the test results. This facility is under commissioning now, and further developments have to be made in order to reduce the beam spot size. Recently, the stability of the power supply for the high gradient quadrupole triplet has been improved to 2 10 5 which is much better than before. In addition, the energy dispersion from the cyclotrons, which causes a deterioration of the spatial resolution, is improved to minimize the spot size. Acknowledgements The authors would like to thank B.E. Fischer from GSI for constructive advices about this facility. They also would like to thank G.W. Grime from University of Surrey, U. Rohrer from PSI, D.N. Jamieson from University of Melbourne for some helpful discussions and providing the computer software codes MULE and TRAX, TRANSPORT and TURTLE, and PRAM respectively. They would like to acknowledge the help from all of the accelerator staff during commissioning. This study was greatly supported by Development of the Key Equipment for Research of CAS. (O713040YZ0) References
Fig. 5. Beam spot from irradiated PC track-etch plastic.
[1] B.E. Fischer, M. Heib, M. Cholewa, Nucl. Instr. and Meth. B 210 (2003) 285–291. [2] M. Oikawa, T. Satoh, T. Kamiya, S. Kurashima, S. Okumura, N. Miyawaki, H. Kashiwagi, M. Fukuda, T. Sakai, W. Yokota, Appl. Radiat. Isot. 67 (2009) 484– 487. [3] G. Randers-Pehrson, G.W. Johnson, S.A. Marino, Y. Xu, A.D. Dymnikov, D.J. Brenner, Nucl. Instr. and Meth. A 609 (2009) 294–299. [4] M. Rothermel, T. Butz, T. Reinert, Nucl. Instr. and Meth. B 267 (2009) 2017– 2020. [5] K.-D. Greif, H.J. Brede, D. Frankenberg, U. Giesen, Nucl. Instr. and Meth. B 217 (2004) 505–512.
2192
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
[6] M.J. Merchant, P. Mistry, M. Browton, A.S. Clough, F.E. Gauntlett, C. Jeynes, K.J. Kirkby, G.W. Grime, Nucl. Instr. and Meth. B 231 (2005) 26–31. [7] K.A. Brown, R. Fliller, Z. Li, S. Peggs, R. Prigl, V. Radeka, M.E. Vazquez, Proceedings of EPAC 2002, Paris, France, pp. 554–556. [8] E.R. Benton, E.V. Benton, Nucl. Instr. and Meth. B 184 (2001) 255–294. [9] W. Schimmerling, Radiat. Environ. Biophys. 34 (1995) 133–137. [10] E.A. Blakely, 1st International Workshop on Space Radiation Research and 11th Annual NASA Space Radiation Health Investigators’ Workshop, Arona, Italy, 2000, 50–58.
[11] S. Metzger, B.E. Fischer, Microelectron. Eng. 31 (1996) 41–46. [12] J.C. Pickel, IEEE Trans. Nucl. Sci. 43 (1996) 483–495. [13] G.H. Gillespie, B.W. Hill, N.A. Brown, R.C. Babcock, G.H. Gillespie Associates Inc., in: D.C. Carey (Ed.), Proceedings of the XVIII International Linear Accelerator Conference 2 (1996) 842–844. [14] A. Dolinskii, P. Beller, K. Beckert, B. Franzke, F. Nolden, M. Steck, Proceedings of EPAC 2002, Paris, France, 572–574. [15] Zgoubi code. Available from:
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb
High energy heavy ion microbeam irradiation facility at IMP Lina Sheng ⇑, Mingtao Song, Xiaoqi Zhang, Xiaotian Yang, Daqing Gao, Yuan He, Bin Zhang, Jie Liu, Youmei Sun, Bingrong Dang, Wenjian Li, Hong Su, Kaidi Man, Yizhen Guo, Zhiguang Wang, Guoqing Xiao Institute of Modern Physics, Chinese Academy of Sciences, P.O. Box 31, 509 Nanchang Rd., Lanzhou 730000, China
a r t i c l e
i n f o
Article history: Available online 1 March 2011 Keywords: Heavy ion High energy Microbeam Quadrupole lens
a b s t r a c t A high energy heavy ion microbeam irradiation facility was designed and installed in the Institute of Modern Physics (IMP) of Chinese Academy of Sciences (CAS). It can deliver well-focused ions into the targets at exact locations. With the advantage of allowing vertical irradiation as well as focusing ions from Carbon to Uranium with high energies in a broad energy range (7 MeV/u to 100 MeV/u for Carbon ions), this setup is able to deliver a preset number of ions into pre-selected target positions. Material specimens in vacuum and living cells in air can also be irradiated by this facility. Detailed description of this microbeam facility as well as its beam optics is presented in this paper. Some preliminary test results are also given. Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction Comparing to the broad beam, a microbeam has many advantages such as the ability to irradiate the targets on the micron scale, which makes it widely applicable in material science, biology, biomedicine, micromachining and so on. Up to date, various microbeam facilities have been developed or are under development in the world [1–6]. For example, heavy ions with a maximum energy of 27.5 MeV/u can be provided at the microbeam facility in JAEA Takasaki (TIARA). The recent development of astronautics indicates that the microbeam using high atomic number and high energy (HZE) ions can be more effective to study the so called late effect in astronauts, as well as the single event phenomena in semiconductor devices for space crafts for the irradiation characteristics in space [7–12]. Therefore, it is preferable to build a microbeam with HZE. In the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) a microbeam facility was designed and installed, in which the maximum energy is designed to be up to 100 MeV/u for Carbon ions and the target is designed to be irradiated both in vacuum and in air. Therefore, this microbeam facility will make a significant impact on many scientific research fields mentioned above in the near future. 2. IMP microbeam facility and beam optics 2.1. Microbeam line The IMP microbeam line was built at the Heavy Ion Research Facility in Lanzhou (HIRFL), in which a variety of ions from Carbon ⇑ Corresponding author. Tel.: +86 18919199596. E-mail address: [email protected] (L. Sheng). 0168-583X/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2011.02.075
to Uranium can be supplied. The ions, produced in the electron cyclotron resonance ion source (ECRIS), are accelerated up to 100 MeV/u for Carbon ions in a cascade operation of cyclotrons, SFC and SSC, and then delivered into the microbeam line. The microbeam line is settled at the basement. Fig. 1 shows the layout of the IMP microbeam line. At first, the ions are focused by a quadrupole triplet (R0Q1-R0Q3) onto an object slit. The object slit with adjustable range from 0 to 150 lm, manufactured by Technisches Büro S. Fischer, is installed before two 45 degree dipole magnets (R0B1-R0B2). The two dipoles and a quadrupole (R0Q4) in between form a symmetric achromatic configuration, which transfer the ions into the microbeam line in the basement. Using the two 45 degree dipole magnets as an energy analyzer, the momentum spread of the ions is determined by the momentum spread defining slit just after R0Q4. The divergence angle of the ion beam is defined using a divergence angle defining slit in combination with the object slit. This slit is similar to the object slit but with an adjustable range from 0 to 1500 lm. A beam switch is set right after the divergence angle defining slit, which consists of two parallel electrodes connected to a high-voltage generator. It is used to switch the beam on and off in order to control that the preset number of ions irradiates the target. The ions can be positioned to the defined target area for spot irradiation, using X and Y scanning magnets. As a final adjustment, a high gradient quadrupole triplet (R0Q5-R0Q7) with a bore diameter of 15 mm is used to focus the ions down to the micron scale. An anti-scattering slit is located directly in front of this high gradient quadrupole triplet to prevent the scattered ions from entering into the quadrupole lenses. All the components are mounted on a heavy rigid support with vibration isolation.
2190
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
Fig. 1. Layout of the IMP microbeam line.
Fig. 2. Details of the IMP microbeam facility.
Fig. 3. Beam envelope of the IMP microbeam line in vacuum calculated by the TRACE-3D code (D denotes drift space, E denotes hard edge fringe field, B denotes dipole magnet, Q denotes quadrupole lens; the numbers in this figure denote the number of the element).
2.2. Experiment platform This facility serves to irradiate both material specimens in vacuum and living cells in air. The vacuum chamber is designed for material irradiation in vacuum, including an optical microscope, a 3-axis sample stage, and a channeltron. The channeltron is used to collect secondary electrons, which enables to count single ion. By contrast, the living cells need to be irradiated in solution or in a humidified atmosphere and at normal air pressure. The inverted
Table 1 Beam optics parameters in vacuum calculated by the TRANSPORT code. Demagnification Chromatic aberration coefficients Spherical aberration coefficients
15.2 15.2 329.7 lm/(mrad%) 182.0 lm/(mrad%) 175.1 lm/mrad3 166.0 lm/mrad3 33.71 lm/mrad3 165.9 lm/mrad3
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
2191
Fig. 4. Beam spot for successive three seconds monitored on the microscope with 4 objective.
fluorescence microscope is the main instrument for living cells experiments and is installed in air below the vacuum chamber. The ions are delivered through a Si3N4 vacuum window with a thickness of 200 nm to the air safely. Furthermore, the window is used as an electron emitter for the channeltron. Fig. 2 shows the details of the IMP microbeam facility. 2.3. Beam optics The beam optics was simulated by the TRANSPORT, TRACE-3D [13], MIRKO [14] and Zgoubi [15] codes for the IMP microbeam line, which has a non-straight configuration. Fig. 3 shows the beam envelope of the IMP microbeam line in vacuum calculated by the TRACE-3D code. This microbeam system has two foci: one in vacuum and the other in air. For this, the working distances are 410 mm and 510 mm, respectively. In this paper, the beam optics parameters, calculated by the TRANSPORT code, are given for the transport line in vacuum (Table 1). These parameters are obtained after the optimization of the final beam spot sizes 1 lm in vacuum and 2 lm in air. The following conditions are required: the object sizes are both 7 lm, the divergence angles are both 0.05 mrad, the momentum spread is 0.01%. 3. Recent test results After the commissioning in 2009, many measurements have been made for testing the performance of the microbeam line. A beam monitor device developed in IMP, combining a CaF2(Eu) scin-
tillator and the inverted fluorescence microscope, is used to monitor the beam spot in air, although its resolution is about 2 lm with 4 objective. Fig. 4 shows a 12 lm beam spot for 40Ar15+ with an energy of 25 MeV/u extracted from the beam monitor device. In order to get a higher detection precision, a Cu grid with a bar width of 9 lm and a hole width of 16 lm is placed in the target plane in air to measure the transmitted energy of the ions using a silicon particle detector behind the Cu grid. The precision for this detector is high enough to monitor 1 lm beam spot. In addition, a polycarbonate (PC) track-etch plastic is used to verify the precise beam spot size. It has a high precision but with a long time for etching. Fig. 5 shows a 38 lm beam spot size in air from irradiated PC track-etch plastic for 40Ar15+ ions with an energy of 25 MeV/u. For the ion detection, the scintillator film BC400 was used at the target position in combination with a photodiode placed at one of the objectives of the inverted fluorescence microscope. In future, the secondary electron detector, which is under test now, will provide information about the number of ions delivered at the target. 4. Conclusion and outlook A well-focused high energy heavy ion microbeam irradiation facility has been constructed in IMP, CAS. The details of the IMP microbeam facility are presented with the beam optics parameters and the test results. This facility is under commissioning now, and further developments have to be made in order to reduce the beam spot size. Recently, the stability of the power supply for the high gradient quadrupole triplet has been improved to 2 10 5 which is much better than before. In addition, the energy dispersion from the cyclotrons, which causes a deterioration of the spatial resolution, is improved to minimize the spot size. Acknowledgements The authors would like to thank B.E. Fischer from GSI for constructive advices about this facility. They also would like to thank G.W. Grime from University of Surrey, U. Rohrer from PSI, D.N. Jamieson from University of Melbourne for some helpful discussions and providing the computer software codes MULE and TRAX, TRANSPORT and TURTLE, and PRAM respectively. They would like to acknowledge the help from all of the accelerator staff during commissioning. This study was greatly supported by Development of the Key Equipment for Research of CAS. (O713040YZ0) References
Fig. 5. Beam spot from irradiated PC track-etch plastic.
[1] B.E. Fischer, M. Heib, M. Cholewa, Nucl. Instr. and Meth. B 210 (2003) 285–291. [2] M. Oikawa, T. Satoh, T. Kamiya, S. Kurashima, S. Okumura, N. Miyawaki, H. Kashiwagi, M. Fukuda, T. Sakai, W. Yokota, Appl. Radiat. Isot. 67 (2009) 484– 487. [3] G. Randers-Pehrson, G.W. Johnson, S.A. Marino, Y. Xu, A.D. Dymnikov, D.J. Brenner, Nucl. Instr. and Meth. A 609 (2009) 294–299. [4] M. Rothermel, T. Butz, T. Reinert, Nucl. Instr. and Meth. B 267 (2009) 2017– 2020. [5] K.-D. Greif, H.J. Brede, D. Frankenberg, U. Giesen, Nucl. Instr. and Meth. B 217 (2004) 505–512.
2192
L. Sheng et al. / Nuclear Instruments and Methods in Physics Research B 269 (2011) 2189–2192
[6] M.J. Merchant, P. Mistry, M. Browton, A.S. Clough, F.E. Gauntlett, C. Jeynes, K.J. Kirkby, G.W. Grime, Nucl. Instr. and Meth. B 231 (2005) 26–31. [7] K.A. Brown, R. Fliller, Z. Li, S. Peggs, R. Prigl, V. Radeka, M.E. Vazquez, Proceedings of EPAC 2002, Paris, France, pp. 554–556. [8] E.R. Benton, E.V. Benton, Nucl. Instr. and Meth. B 184 (2001) 255–294. [9] W. Schimmerling, Radiat. Environ. Biophys. 34 (1995) 133–137. [10] E.A. Blakely, 1st International Workshop on Space Radiation Research and 11th Annual NASA Space Radiation Health Investigators’ Workshop, Arona, Italy, 2000, 50–58.
[11] S. Metzger, B.E. Fischer, Microelectron. Eng. 31 (1996) 41–46. [12] J.C. Pickel, IEEE Trans. Nucl. Sci. 43 (1996) 483–495. [13] G.H. Gillespie, B.W. Hill, N.A. Brown, R.C. Babcock, G.H. Gillespie Associates Inc., in: D.C. Carey (Ed.), Proceedings of the XVIII International Linear Accelerator Conference 2 (1996) 842–844. [14] A. Dolinskii, P. Beller, K. Beckert, B. Franzke, F. Nolden, M. Steck, Proceedings of EPAC 2002, Paris, France, 572–574. [15] Zgoubi code. Available from: