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The vacuum system of the Milan superconducting cyclotron cryostat
Vacuum/volume Printed
38/numbers
8-l
O/pages 945 to 95211988
0042-207x/88$3.00+.00 Pergamon Press plc
in Great Britain
Abstracts
The vacuum system Cryostat
of the Milan Superconducting
F Aghion, D Giove and P Michelato, University Istituto Nazionale Fisica Nucleare, Milan, Italy
Cyclotron
of Milan and
The cryostat of the Superconducting Cyclotron under construction at the University of Milan uses vacuum as thermal insulation between the room temperature parts, the LN, shield and the liquid helium container. A pumping system with a long operative life and high reliability has been designed to allow recovery if the helium liquid vessel leaks. These characteristics are required to prevent the discharge of the energy stored in the coils (nearly 40 MJ) due to a pressure rise in the insulation chamber. An important restriction in the choice of the elements arises from the magnetic field (0.5 T) experienced by the vacuum system. Two independent diffusion pump units are connected to the vacuum chamber and both high and forevacuum pumps are filled with the same oil. A full automatic control system guarantees fail safe and mistake free operation, also during maintenance. A Westinghouse PLC based system controls each plant in a stand-alone way; the connection to the control network of the accelerator is accomplished by means of a high speed SDLC-like serial bus, implemented on microcontroller based boards. Remote handling and data recording of the plants are performed by a PC-IBM for preliminary test and a pVAX II for on line operation.
Mimas vacuum system and modification of SATURNE tron vacuum system
synchro-
C Henriot, P Campet, G Congretel and N Rouviere, Laboratoire National SATURNE, CEN/Saclay, France The Laboratoire National SATURNE, as part of its continuing experimental programme, has built an accumulator ring injector for heavy ions. The vacuum chamber of the ring is a tubular structure ; in shape it is roughly circular, measuring 33 m in circumference. This vacuum chamber has been designed to operate in the ultra-high vacuum (1O-9 Pa) range. The main pumping is ensured by evaporable getter pumps (titanium). Moreover, when SATURNE Synchrotron accelerator was built for protons, deuterons and polarized particles, a pressure of lo-’ Pa was sufficient. To achieve a factor of 100, we had to modify the pumping design and to install baking which had not been forseen.
Fundamental plasma reactions and phenomena related to thin-film technology Achim Bubenzer, Messerschmitt-Biilkow-Blohm FRG
GmbH, Miinchen,
The basics of plasma processes as related to thin-film deposition are reviewed. The fundamental phenomena of three important plasma sustained thin film deposition techniques, namely sputtering, plasma enhanced chemical vapour deposition (PECVD) and plasma polymerisation are described. Amorphous carbon (a-C) and amorphous silicon (a-Si) are typical and technologically important materials to be deposited by these techniques. Therefore the fundamentals 5f a-C and a-Si deposition (as far as they are known today) are reported as examples for plasma related thin film deposition.
Removal of corrosive exhaust gases in RIE system by a chemical trap F Braunschweig, Alcatel D-6980 Wertheim, FRG
Hochvakuumtechnik,
Am Bildacker
I,
Dry etching processes in microelectronics fabrication produce highly poisonous and corrosive gases. These are harmful for pumping equipment and they lead to environmental pollution. A procedure has been developed to remove these gases from the exhaust line by chemical reaction before they enter the pumping system. The reaction and the reactor design are discussed and results of efficiency measurements are presented.
More and more from less and less and how it happens-some consideratiods of the preparation of thin films by chemical vapour deposition under reduced pressure Michael L Hitchman, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow GI IXL, UK For many years the standard method in the semiconductor industry for the growth of single crystal, polycrystaliine and amorphous semiconductor materials has been the technique of chemical vapour deposition (CVD) in atmospheric pressure reactors. In the last few years, however, there has been an enormous increase in the use of reduced pressure systems. This rapid 945
38/numbers
8-l
O/pages 945 to 95211988
0042-207x/88$3.00+.00 Pergamon Press plc
in Great Britain
Abstracts
The vacuum system Cryostat
of the Milan Superconducting
F Aghion, D Giove and P Michelato, University Istituto Nazionale Fisica Nucleare, Milan, Italy
Cyclotron
of Milan and
The cryostat of the Superconducting Cyclotron under construction at the University of Milan uses vacuum as thermal insulation between the room temperature parts, the LN, shield and the liquid helium container. A pumping system with a long operative life and high reliability has been designed to allow recovery if the helium liquid vessel leaks. These characteristics are required to prevent the discharge of the energy stored in the coils (nearly 40 MJ) due to a pressure rise in the insulation chamber. An important restriction in the choice of the elements arises from the magnetic field (0.5 T) experienced by the vacuum system. Two independent diffusion pump units are connected to the vacuum chamber and both high and forevacuum pumps are filled with the same oil. A full automatic control system guarantees fail safe and mistake free operation, also during maintenance. A Westinghouse PLC based system controls each plant in a stand-alone way; the connection to the control network of the accelerator is accomplished by means of a high speed SDLC-like serial bus, implemented on microcontroller based boards. Remote handling and data recording of the plants are performed by a PC-IBM for preliminary test and a pVAX II for on line operation.
Mimas vacuum system and modification of SATURNE tron vacuum system
synchro-
C Henriot, P Campet, G Congretel and N Rouviere, Laboratoire National SATURNE, CEN/Saclay, France The Laboratoire National SATURNE, as part of its continuing experimental programme, has built an accumulator ring injector for heavy ions. The vacuum chamber of the ring is a tubular structure ; in shape it is roughly circular, measuring 33 m in circumference. This vacuum chamber has been designed to operate in the ultra-high vacuum (1O-9 Pa) range. The main pumping is ensured by evaporable getter pumps (titanium). Moreover, when SATURNE Synchrotron accelerator was built for protons, deuterons and polarized particles, a pressure of lo-’ Pa was sufficient. To achieve a factor of 100, we had to modify the pumping design and to install baking which had not been forseen.
Fundamental plasma reactions and phenomena related to thin-film technology Achim Bubenzer, Messerschmitt-Biilkow-Blohm FRG
GmbH, Miinchen,
The basics of plasma processes as related to thin-film deposition are reviewed. The fundamental phenomena of three important plasma sustained thin film deposition techniques, namely sputtering, plasma enhanced chemical vapour deposition (PECVD) and plasma polymerisation are described. Amorphous carbon (a-C) and amorphous silicon (a-Si) are typical and technologically important materials to be deposited by these techniques. Therefore the fundamentals 5f a-C and a-Si deposition (as far as they are known today) are reported as examples for plasma related thin film deposition.
Removal of corrosive exhaust gases in RIE system by a chemical trap F Braunschweig, Alcatel D-6980 Wertheim, FRG
Hochvakuumtechnik,
Am Bildacker
I,
Dry etching processes in microelectronics fabrication produce highly poisonous and corrosive gases. These are harmful for pumping equipment and they lead to environmental pollution. A procedure has been developed to remove these gases from the exhaust line by chemical reaction before they enter the pumping system. The reaction and the reactor design are discussed and results of efficiency measurements are presented.
More and more from less and less and how it happens-some consideratiods of the preparation of thin films by chemical vapour deposition under reduced pressure Michael L Hitchman, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow GI IXL, UK For many years the standard method in the semiconductor industry for the growth of single crystal, polycrystaliine and amorphous semiconductor materials has been the technique of chemical vapour deposition (CVD) in atmospheric pressure reactors. In the last few years, however, there has been an enormous increase in the use of reduced pressure systems. This rapid 945