WO2011154563A1 - Drift tube for linear accelerator (linac) with four-pole permanent magnets without welded caps - Google Patents
Drift tube for linear accelerator (linac) with four-pole permanent magnets without welded caps Download PDFInfo
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- WO2011154563A1 WO2011154563A1 PCT/ES2010/070386 ES2010070386W WO2011154563A1 WO 2011154563 A1 WO2011154563 A1 WO 2011154563A1 ES 2010070386 W ES2010070386 W ES 2010070386W WO 2011154563 A1 WO2011154563 A1 WO 2011154563A1
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- drift tube
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- core
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- linear accelerator
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
- H05H7/22—Details of linear accelerators, e.g. drift tubes
Definitions
- the present invention relates to a process of manufacturing a drift tube for a linear accelerator, in particular to a process that leads to a tube with a better connection of its parts.
- Linear accelerators are devices that use radiofrequency energy to accelerate charged particles such as electrons, protons and ions.
- the charged particles of an ionic source enter a cylindrical enclosure known as a tank that encloses coaxially separated devices known as drift tubes.
- RF energy is present in the tank to accelerate the charged particles through the gaps between adjacent drift tubes.
- the structure of a linear accelerator is such that the particles are shielded within each drift tube from the effects of RF stress reversals. Therefore, when the charged particles emerge from each drift tube and enter the next hole, they accelerate further. It is necessary to provide means to focus the beam of charged particles along the axis of the tank to counteract its tendency to diverge. For this, different types of magnets are used.
- a drift tube includes a central hollow cylindrical body having an annular permanent magnet assembly mounted therein.
- the inside of the drift tube is sealed by caps or faceplates that form transverse boundaries for gaps between drift tubes located adjacently.
- the present invention proposes a two-stage process that can create a high quality joint alternative to electron beam welding.
- This sealing gasket creates a continuous thermal and electrical interface, which can remain so after extreme thermal cycles and thus prevent the appearance of gaps and other imperfections and, therefore, guarantee the cooling capacity of the drift tube.
- the process of the invention comprises the steps of providing a drift tube cover composed of oxygen-free pure electrolytic copper, pressing the surface of the drift tube cover into a core of the drift tube also composed of free electrolytic copper of oxygen so that the contact is airtight, electrodeposing copper over the joint, and forming a continuous sealing copper strip that completely fills the gaps between the core and the drift tube cover.
- the cover is provided with a groove in the adjustment end and the joint is between 2 and 3 mm thick.
- Figure 1 .- is a cross-sectional view of a long drift tube manufactured according to the present invention.
- Figure 2 is a cross-sectional view of a short drift tube manufactured according to the present invention.
- the present procedure basically employs a two-stage process to seal the existing gasket between the drift tube core cover and its central body / core.
- the entire drift tube including the joint seam between the core and the cap, can be made of pure copper, also called oxygen-free high conductivity copper (OFHC copper) or oxygen free electrolytic copper (OFE copper), without the presence or inclusions of additional non-copper materials such as those present in welding alloys. Therefore, the need for a previous preparatory welding operation is exceeded.
- the first basic step is to insert the surface of the core cover under pressure into the core of the drift tube with sufficient interference, so that the contact is tight and is maintained during electro-forming. The tightness is guaranteed by careful interference control, which takes advantage of the softness of pure copper. Actually, if the dimensions of the pieces are correctly defined, the copper pieces fit together in such a way that the "male" piece, the drift tube cover in our case, mimics the internal shape of the female, our drift tube core.
- the design of the surfaces that come into contact and the close details also define the hollow contour that must be covered by electro-forming in the following stages of the manufacturing process. Therefore, the geometry of the corners is defined to facilitate the deposition of copper in a homogeneous and rigid manner.
- Another advantage of the present invention is that low temperature welding and the associated intermediate welding material are unnecessary.
- oxygen-free high conductivity electrolytic copper (sometimes referred to as oxygen-free electrolytic copper) is used in manufacturing, thus avoiding the appearance of lower thermal conductivity figures as a result of additional non-copper materials.
- Only a direct contact of copper surface with copper surface is maintained within the drift tube.
- the surface to which electroconformation has been applied is of sufficient thickness, it has been shown that the effect of the contact on the thermal conduction capabilities of the drift tube is negligible.
- This solution with pure copper means that no additional RF power is required to power the acceleration structure, since losses due to thermal conductivity and inefficient contacts and material interfaces are avoided.
- One function and side effect of the pressure adjustment is to keep the core and the drift tube cover in place during the electroconforming process that follows. Moreover, the pressure adjustment ensures that mechanical integrity is ensured during transport and the process.
- the designed joint is covered with copper applied by electro-forming in such a way that the continuity of material between the pieces is guaranteed.
- This layer applied by electro-forming must fill the gaps between the core and the drift tube cover completely, creating a continuous layer of copper material, without pores, gaps, inclusions and other possible defects. Thanks to the process of the invention, it is possible to create a small grain size layer in the seam. In this way, the thermal conductivity is improved, which is similar to the copper formed in 3D that is used in normal driving accelerators.
- a second condition for the layer is that it must be of sufficient thickness to ensure that heat transfer and possible electrical currents can concentrate on the surface, thus reducing the impact of the lack of continuity represented by the pressure adjustment.
- a thickness of approximately 2-3 mm is necessary for a correct strip of sealing copper applied by electro-forming. The thermal jump due to the absence of a metallurgical bond between the surfaces of the pieces becomes negligible if the electrodeposited layer is made of a sufficient thickness. In addition, the thermal jump is not in the direction of the main thermal flux, therefore the associated thermal resistance is minimal. If necessary, the procedure can be completed with a silver fill varnish, common in many other electrodeposition techniques.
- the core cover (2) is pre-machined so that its sharp edge in favor of a cylindrical shape is removed. This cylindrical end can now become the male part of the pressure adjustment.
- the cylindrical part may also comprise a groove (4) to facilitate copper deposition and facilitate heat transfer in the direction of the ion beam.
- the groove is located far enough from the edge of the lid, so that it remains free after pressure adjustment. In this way, the pressure adjustment interface is limited to a radial direction. Electro-forming processes require smooth edges and wide deposition angles, which define, at the end, bevel angles, as illustrated.
- the core of the drift tube (3) comprises a new internal cylindrical end (5) that would not be necessary if the welding were to be created by electron beam welding.
- This shape is the female part of the snap fit.
- the length of interfering surfaces should be as short as possible to avoid discontinuities in the radial direction. Smooth edges are also included to ensure proper deposition of the copper applied by electro-forming.
- An electroconformed variant is then used to create a permanent, completely metal connection (6) between the core and the drift tube cover, by deposition of a layer of thickness of the order of the millimeter over the groove to the corner corners large.
- the deposited metal does not cover any mandrel, copying the surface and geometric characteristic, and then it is discarded. Instead, deposited copper creates homogeneity and structural, electrical and thermal integrity.
- the process of periodic inversion of electro-forming is preferred for this purpose.
- the groove geometry maximizes concave surfaces, while minimizing convex geometries, to avoid a concentration of ions and charge that could prevent the homogeneous growth of deposited copper. Trapped pores, cracks and specimens are solids, liquids or gaseous trapped, by minimizing manipulation during the process, adjusting process parameters such as turbulence and current density and continuously moving the entire assembly into the bathroom.
- a precise anode must also be constructed and used to ensure correct grain size and homogeneous deposition, without nodular growth of the metal surface.
- the assembly (1) is mechanically polished to improve the quality of the surface roughness, which is critical for the performance of the drift tube.
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Abstract
A method for producing a drift tube for a linear accelerator, the method comprising the steps of: providing a cap for the drift tube composed of oxygen-free electrolytic pure copper; pressure-inserting the surface of the cap for the drift tube into a core of the drift tube composed, likewise, of oxygen-free electrolytic copper, such that the contact is hermetically sealed; electrodepositing copper onto the seal; and forming a continuous copper sealing strip that completely fills the voids between the core and the cap of the drift tube. The method dispenses with the need for welding and allows the use of oxygen-free copper.
Description
TUBO DE DERIVA PARA ACELERADOR LINEAL (LINAC) CON IMANES DERIVA TUBE FOR LINEAR ACCELERATOR (LINAC) WITH MAGNETS
CUADRUPOLARES PERMANENTES SIN TAPAS SOLDADAS PERMANENT QUADRUPOLAR WITHOUT WELDED COVERS
CAMPO DE LA INVENCIÓN FIELD OF THE INVENTION
La presente invención se refiere a un proceso de fabricación de un tubo de deriva para un acelerador lineal, en particular a un proceso que conduce a un tubo con una mejor unión de sus piezas. The present invention relates to a process of manufacturing a drift tube for a linear accelerator, in particular to a process that leads to a tube with a better connection of its parts.
ESTADO DE LA TÉCNICA STATE OF THE TECHNIQUE
Los aceleradores lineales, o LINAC, son dispositivos que usan energía de radiofrecuencia para acelerar partículas cargadas tales como electrones, protones e iones. Las partículas cargadas de una fuente iónica entran en un recinto cilindrico conocido como tanque que encierra dispositivos separados coaxialmente conocidos como tubos de deriva. La energía de RF está presente en el tanque para acelerar las partículas cargadas a través de los huecos entre tubos de deriva adyacentes. La estructura de un acelerador lineal es de tal manera que las partículas se apantallan dentro de cada tubo de deriva de los efectos de las inversiones de tensión de RF. Por tanto, cuando las partículas cargadas emergen de cada tubo de deriva y entran en el siguiente hueco, se aceleran más. Es necesario proporcionar medios para enfocar el haz de partículas cargadas a lo largo del eje del tanque para contrarrestar su tendencia a divergir. Para ello se emplean diferentes tipos de imanes. Inicialmente se usaban cuadrupolos electromagnéticos especialmente diseñados. Últimamente está debatiéndose la utilización de imanes permanentes cuadrupolares y diversos proyectos de construcción y diseño de LINAC en curso (LINAC4, ESS, etc.) los incluyen como principal novedad. Estos imanes se fabrican de segmentos de cobalto de tierras raras, habitualmente samario-cobalto. Linear accelerators, or LINAC, are devices that use radiofrequency energy to accelerate charged particles such as electrons, protons and ions. The charged particles of an ionic source enter a cylindrical enclosure known as a tank that encloses coaxially separated devices known as drift tubes. RF energy is present in the tank to accelerate the charged particles through the gaps between adjacent drift tubes. The structure of a linear accelerator is such that the particles are shielded within each drift tube from the effects of RF stress reversals. Therefore, when the charged particles emerge from each drift tube and enter the next hole, they accelerate further. It is necessary to provide means to focus the beam of charged particles along the axis of the tank to counteract its tendency to diverge. For this, different types of magnets are used. Initially, specially designed electromagnetic quadrupoles were used. Lately, the use of permanent quadrupole magnets and various ongoing construction and design projects of LINAC (LINAC4, ESS, etc.) are including them as the main novelty. These magnets are made of rare earth cobalt segments, usually samarium-cobalt.
Actualmente, un tubo de deriva incluye un cuerpo cilindrico hueco central que tiene un conjunto de imán permanente anular montado en el mismo. El interior del tubo de deriva se sella mediante tapas o placas frontales que forman límites transversales para huecos entre tubos de deriva situados de manera adyacente. Currently, a drift tube includes a central hollow cylindrical body having an annular permanent magnet assembly mounted therein. The inside of the drift tube is sealed by caps or faceplates that form transverse boundaries for gaps between drift tubes located adjacently.
Un problema de fabricación surge debido a la sensibilidad térmica del conjunto de imán permanente. Particularmente, con imanes permanentes de samario-cobalto de tierras raras, es importante evitar la exposición del conjunto de imán a temperaturas por encima de 1005C. Por encima de esta temperatura, las propiedades magnéticas cuadrupolares disminuyen. A manufacturing problem arises due to the thermal sensitivity of the permanent magnet assembly. Particularly, with permanent rare earth samarium-cobalt magnets, it is important to avoid exposing the magnet assembly at temperatures above 100 5 C. Above this temperature, quadrupole magnetic properties decrease.
Con los actuales conjuntos de tubo de deriva, se realizan habitualmente
intentos para realizar soldadura por haz de electrones en los contactos entre las piezas de núcleo y tapas. Sin embargo, esto requiere un cuidadoso control debido a la sensibilidad térmica del conjunto de imán. Además, es difícil usar soldadura por haz de electrones ya que el haz de electrones se ve influenciado por el fuerte campo magnético del conjunto de imán. Este problema no aparecía en los antiguos conjuntos de tubo de deriva, ya que los electroimanes no exhibían ningún campo magnético durante la fabricación. Sin embargo, debido a las ventajas que demuestran los imanes permanentes, se espera que las nuevas generaciones de LINAC abandonen los electroimanes a favor de los permanentes. Por tanto, es necesaria una solución de fabricación fiable para superar la presencia del campo magnético. With current drift tube assemblies, they are usually performed attempts to perform electron beam welding at the contacts between the core pieces and caps. However, this requires careful control due to the thermal sensitivity of the magnet assembly. In addition, it is difficult to use electron beam welding since the electron beam is influenced by the strong magnetic field of the magnet assembly. This problem did not appear in the old drift tube assemblies, since the electromagnets did not exhibit any magnetic field during manufacturing. However, due to the advantages shown by permanent magnets, new generations of LINAC are expected to abandon electromagnets in favor of permanent ones. Therefore, a reliable manufacturing solution is necessary to overcome the presence of the magnetic field.
Los esfuerzos en l+D a este respecto se centran en apantallar el campo magnético existente y compensar sus efectos. The efforts in R&D in this regard are focused on shielding the existing magnetic field and compensating its effects.
Un procedimiento de electroconformado sería extremadamente deseable debido al hecho de que el proceso se realiza a temperatura ambiente. Sin embargo, cuando se aplica electroconformado a la junta entre la placa frontal y el núcleo pueden producirse fugas de líquido de baño de electroconformado (normalmente ácido sulfúrico) al interior del tubo de deriva. La creación de un hueco en la junta afectaría gravemente a la capacidad de enfriamiento del tubo de deriva. An electro-forming procedure would be extremely desirable due to the fact that the process is performed at room temperature. However, when electroconforming is applied to the joint between the front plate and the core, electroconformation bath liquids (usually sulfuric acid) can leak into the drift tube. The creation of a hole in the joint would seriously affect the cooling capacity of the drift tube.
OBJETO DE LA INVENCIÓN OBJECT OF THE INVENTION
La presente invención propone un proceso en dos etapas que puede crear una unión de alta calidad alternativa a la soldadura por haz de electrones. Esta junta de sellado crea una interfase térmica y eléctrica continua, que puede permanecer así después de ciclos térmicos extremos y evitar de este modo la aparición de huecos y otras imperfecciones y, por tanto, garantizar la capacidad de enfriamiento del tubo de deriva. The present invention proposes a two-stage process that can create a high quality joint alternative to electron beam welding. This sealing gasket creates a continuous thermal and electrical interface, which can remain so after extreme thermal cycles and thus prevent the appearance of gaps and other imperfections and, therefore, guarantee the cooling capacity of the drift tube.
El procedimiento de la invención comprende las etapas de proporcionar una tapa del tubo de deriva compuesta por cobre puro electrolítico libre de oxígeno, insertar a presión la superficie de la tapa del tubo de deriva en un núcleo del tubo de deriva también compuesto por cobre electrolítico libre de oxígeno de modo que el contacto sea hermético, electrodepositar cobre sobre la junta, y formar una tira de cobre de sellado continua que rellena completamente los huecos entre el núcleo y la tapa del tubo de deriva. Ventajosamente, la tapa está dotada de una ranura en el extremo de ajuste y la unión tiene entre 2 y 3 mm de espesor. Antes de insertar la tapa en el tubo de deriva, éste se enfría.
BREVE DESCRIPCIÓN DE LOS DIBUJOS The process of the invention comprises the steps of providing a drift tube cover composed of oxygen-free pure electrolytic copper, pressing the surface of the drift tube cover into a core of the drift tube also composed of free electrolytic copper of oxygen so that the contact is airtight, electrodeposing copper over the joint, and forming a continuous sealing copper strip that completely fills the gaps between the core and the drift tube cover. Advantageously, the cover is provided with a groove in the adjustment end and the joint is between 2 and 3 mm thick. Before inserting the cap into the drift tube, it is cooled. BRIEF DESCRIPTION OF THE DRAWINGS
Para completar la descripción y con el fin de proporcionar una mejor comprensión de la invención, se proporciona un juego de dibujos. Dichos dibujos forman parte integrante de la descripción e ilustran una realización preferida de la invención, que no ha de interpretarse como que restringe el alcance de la invención, sino simplemente como un ejemplo de cómo puede realizarse la invención. Los dibujos comprenden las siguientes figuras: To complete the description and in order to provide a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate a preferred embodiment of the invention, which is not to be construed as restricting the scope of the invention, but simply as an example of how the invention can be realized. The drawings comprise the following figures:
la figura 1 .- es una vista en sección transversal de un tubo de deriva largo fabricado según la presente invención; Figure 1 .- is a cross-sectional view of a long drift tube manufactured according to the present invention;
la figura 2.- es una vista en sección transversal de un tubo de deriva corto fabricado según la presente invención. Figure 2 is a cross-sectional view of a short drift tube manufactured according to the present invention.
DESCRIPCIÓN DE LA INVENCIÓN DESCRIPTION OF THE INVENTION
El presente procedimiento emplea, básicamente, un proceso en dos etapas para sellar la junta existente entre la tapa del núcleo del tubo de deriva y su cuerpo central / núcleo. Gracias al proceso de la invención, todo el tubo de deriva, incluyendo la costura de unión entre el núcleo y la tapa, puede fabricarse de cobre puro, también denominado cobre de alta conductividad libre de oxígeno (cobre OFHC) o cobre electrolítico libre de oxígeno (cobre OFE), sin la presencia ni inclusiones de materiales adicionales no de cobre tales como los presentes en las aleaciones de soldadura. Por tanto, se supera la necesidad de una operación de soldadura preparatoria previa. La primera etapa básica es insertar a presión la superficie de la tapa del núcleo en el núcleo del tubo de deriva con una interferencia suficiente, de modo que el contacto sea hermético y se mantenga durante la electroconformado. La hermeticidad se garantiza mediante un cuidadoso control de la interferencia, que aprovecha la blandura del cobre puro. En realidad, si las dimensiones de las piezas están correctamente definidas, las piezas de cobre se ajustan entre sí de tal manera que la pieza "macho", la tapa del tubo de deriva en nuestro caso, imita la forma interna de la hembra, nuestro núcleo del tubo de deriva. The present procedure basically employs a two-stage process to seal the existing gasket between the drift tube core cover and its central body / core. Thanks to the process of the invention, the entire drift tube, including the joint seam between the core and the cap, can be made of pure copper, also called oxygen-free high conductivity copper (OFHC copper) or oxygen free electrolytic copper (OFE copper), without the presence or inclusions of additional non-copper materials such as those present in welding alloys. Therefore, the need for a previous preparatory welding operation is exceeded. The first basic step is to insert the surface of the core cover under pressure into the core of the drift tube with sufficient interference, so that the contact is tight and is maintained during electro-forming. The tightness is guaranteed by careful interference control, which takes advantage of the softness of pure copper. Actually, if the dimensions of the pieces are correctly defined, the copper pieces fit together in such a way that the "male" piece, the drift tube cover in our case, mimics the internal shape of the female, our drift tube core.
El diseño de las superficies que entran en contacto y los detalles próximos también definen el contorno hueco que debe cubrirse mediante la electroconformado en las siguientes etapas del proceso de fabricación. Por tanto, la geometría de las esquinas se define para facilitar la deposición de cobre de una manera homogénea y rígida. The design of the surfaces that come into contact and the close details also define the hollow contour that must be covered by electro-forming in the following stages of the manufacturing process. Therefore, the geometry of the corners is defined to facilitate the deposition of copper in a homogeneous and rigid manner.
Otra ventaja de la presente invención es que la soldadura a baja temperatura y el material de soldadura intermedio asociado resultan innecesarios.
Como consecuencia de esto, sólo se usa cobre electrolítico de alta conductividad libre de oxígeno (denominado en ocasiones cobre electrolítico libre de oxígeno) en la fabricación, evitándose así la aparición de cifras de conductividad térmica inferiores como consecuencia de materiales adicionales no de cobre. Sólo se mantiene un contacto directo de superficie de cobre con superficie de cobre dentro del tubo de deriva. Sin embargo, si la superficie a la que se ha aplicado electroconformado tiene un espesor suficiente, se ha demostrado que el efecto del contacto sobre las capacidades de conducción térmica del tubo de deriva es despreciable. Esta solución con cobre puro significa que no se requiere potencia de RF adicional para alimentar la estructura de aceleración, ya que se evitan pérdidas debidas a la conductividad térmica y a contactos no eficaces e interfases de material. Another advantage of the present invention is that low temperature welding and the associated intermediate welding material are unnecessary. As a consequence, only oxygen-free high conductivity electrolytic copper (sometimes referred to as oxygen-free electrolytic copper) is used in manufacturing, thus avoiding the appearance of lower thermal conductivity figures as a result of additional non-copper materials. Only a direct contact of copper surface with copper surface is maintained within the drift tube. However, if the surface to which electroconformation has been applied is of sufficient thickness, it has been shown that the effect of the contact on the thermal conduction capabilities of the drift tube is negligible. This solution with pure copper means that no additional RF power is required to power the acceleration structure, since losses due to thermal conductivity and inefficient contacts and material interfaces are avoided.
Una función y efecto secundario del ajuste a presión es mantener el núcleo y la tapa del tubo de deriva en su sitio durante el proceso de electroconformado que sigue. Es más, el ajuste a presión garantiza que se asegura la integridad mecánica durante el transporte y el proceso. One function and side effect of the pressure adjustment is to keep the core and the drift tube cover in place during the electroconforming process that follows. Moreover, the pressure adjustment ensures that mechanical integrity is ensured during transport and the process.
Entonces, la junta diseñada se cubre con cobre aplicado mediante electroconformado de tal manera que se garantiza la continuidad de material entre las piezas. Esta capa aplicada mediante electroconformado debe rellenar los huecos entre el núcleo y la tapa del tubo de deriva por completo, creando una capa continua de material de cobre, sin poros, huecos, inclusiones y otros posibles defectos. Gracias al proceso de la invención, es posible crear una capa de tamaño de grano pequeño en la costura. De este modo, se mejora la conductividad térmica, que es similar al cobre formado en 3D que se usa en aceleradores de conducción normales. Then, the designed joint is covered with copper applied by electro-forming in such a way that the continuity of material between the pieces is guaranteed. This layer applied by electro-forming must fill the gaps between the core and the drift tube cover completely, creating a continuous layer of copper material, without pores, gaps, inclusions and other possible defects. Thanks to the process of the invention, it is possible to create a small grain size layer in the seam. In this way, the thermal conductivity is improved, which is similar to the copper formed in 3D that is used in normal driving accelerators.
Una segunda condición para la capa es que debe tener un espesor suficiente para garantizar que la transferencia de calor y posibles corrientes eléctricas puedan concentrarse en la superficie, disminuyendo así el impacto de la falta de continuidad que representa el ajuste a presión. Un espesor de aproximadamente 2-3 mm es necesario para una correcta tira de cobre de sellado aplicada mediante electroconformado. El salto térmico debido a la ausencia de una unión metalúrgica entre las superficies de las piezas se hace despreciable si la capa electrodepositada se hace de un espesor suficiente. Además, el salto térmico no es en la dirección del flujo térmico principal, por tanto la resistencia térmica asociada es mínima. Si es necesario, el procedimiento puede completarse con un barniz de relleno de plata, habitual en muchas otras técnicas de electrodeposición.
DESCRIPCIÓN DE UNA REALIZACIÓN PREFERIDA DE LA INVENCIÓN A second condition for the layer is that it must be of sufficient thickness to ensure that heat transfer and possible electrical currents can concentrate on the surface, thus reducing the impact of the lack of continuity represented by the pressure adjustment. A thickness of approximately 2-3 mm is necessary for a correct strip of sealing copper applied by electro-forming. The thermal jump due to the absence of a metallurgical bond between the surfaces of the pieces becomes negligible if the electrodeposited layer is made of a sufficient thickness. In addition, the thermal jump is not in the direction of the main thermal flux, therefore the associated thermal resistance is minimal. If necessary, the procedure can be completed with a silver fill varnish, common in many other electrodeposition techniques. DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
A continuación se describen las características específicas del ajuste a presión del núcleo y la tapa del tubo de deriva. The specific characteristics of the pressure adjustment of the core and the drift tube cover are described below.
La tapa del núcleo (2) se mecaniza previamente de modo que se elimina su borde afilado a favor de una forma cilindrica. Este extremo cilindrico puede convertirse ahora en la parte macho del ajuste a presión. La parte cilindrica también puede comprender una ranura (4) para facilitar la deposición de cobre y facilitar la transferencia de calor en la dirección del haz de iones. La ranura se sitúa suficientemente lejos del borde de la tapa, de modo que permanezca libre después del ajuste a presión. De este modo, la interfase de ajuste a presión se limita a una dirección radial. Los procesos de electroconformado requieren bordes lisos y ángulos de deposición amplios, que definen, en el extremo, ángulos de biselado, tal como se ilustra. The core cover (2) is pre-machined so that its sharp edge in favor of a cylindrical shape is removed. This cylindrical end can now become the male part of the pressure adjustment. The cylindrical part may also comprise a groove (4) to facilitate copper deposition and facilitate heat transfer in the direction of the ion beam. The groove is located far enough from the edge of the lid, so that it remains free after pressure adjustment. In this way, the pressure adjustment interface is limited to a radial direction. Electro-forming processes require smooth edges and wide deposition angles, which define, at the end, bevel angles, as illustrated.
Por otro lado, el núcleo del tubo de deriva (3) comprende un nuevo extremo cilindrico interno (5) que no sería necesario si la soldadura fuese a crearse mediante soldadura por haz de electrones. Esta forma es la parte hembra del ajuste a presión. La longitud de las superficies que interfieren debe ser lo más baja posible para evitar discontinuidades en la dirección radial. También se incluyen bordes lisos para garantizar una correcta deposición del cobre aplicado mediante electroconformado. On the other hand, the core of the drift tube (3) comprises a new internal cylindrical end (5) that would not be necessary if the welding were to be created by electron beam welding. This shape is the female part of the snap fit. The length of interfering surfaces should be as short as possible to avoid discontinuities in the radial direction. Smooth edges are also included to ensure proper deposition of the copper applied by electro-forming.
Con estos dos elementos, se produce una interferencia de 50 micrómetros entre las dos partes, mediante el enfriamiento de la tapa del tubo de deriva y su introducción en el núcleo del tubo de deriva, y después controlando la dilatación que se produce a medida que se calienta lentamente. With these two elements, 50 micrometer interference occurs between the two parts, by cooling the drift tube lid and introducing it into the core of the drift tube, and then controlling the dilation that occurs as it heat slowly.
Una variante de electroconformado se usa entonces para crear una conexión permanente, completamente de metal (6) entre el núcleo y la tapa del tubo de deriva, mediante la deposición de una capa de espesor del orden del milímetro sobre la ranura hasta las esquinas de ángulo amplio. A diferencia de la electroconformado habitual, el metal depositado no cubre ningún mandril, copiando la superficie y característica geométrica, y luego se desecha. En cambio, el cobre depositado crea la homogeneidad y la integridad estructural, eléctrica y térmica. An electroconformed variant is then used to create a permanent, completely metal connection (6) between the core and the drift tube cover, by deposition of a layer of thickness of the order of the millimeter over the groove to the corner corners large. Unlike the usual electroconformado, the deposited metal does not cover any mandrel, copying the surface and geometric characteristic, and then it is discarded. Instead, deposited copper creates homogeneity and structural, electrical and thermal integrity.
El procedimiento de inversión periódica de electroconformado se prefiere con este fin. La geometría de la ranura maximiza las superficies cóncavas, al tiempo que minimiza las geometrías convexas, para evitar una concentración de iones y de carga que pudiera impedir el crecimiento homogéneo del cobre depositado.
Se evitan poros, fisuras y especímenes sólidos, líquidos o gaseosos atrapados, mediante la minimización de la manipulación durante el proceso, ajustando parámetros de proceso como turbulencia y densidad de corriente y moviendo continuamente todo el conjunto dentro del baño. The process of periodic inversion of electro-forming is preferred for this purpose. The groove geometry maximizes concave surfaces, while minimizing convex geometries, to avoid a concentration of ions and charge that could prevent the homogeneous growth of deposited copper. Trapped pores, cracks and specimens are solids, liquids or gaseous trapped, by minimizing manipulation during the process, adjusting process parameters such as turbulence and current density and continuously moving the entire assembly into the bathroom.
También debe construirse y usarse un ánodo preciso para garantizar un tamaño de grano correcto y una deposición homogénea, sin crecimiento nodular de la superficie metálica. Una vez alojados los elementos a los que se ha aplicado electroconformado, el conjunto se mecaniza de nuevo para garantizar que la forma, dimensiones y orientación relativa de todas las piezas son según los parámetros de diseño originales, definidos con precisión durante el procedimiento de diseño de la cavidad y que dependen del tipo de haz, intervalo de energías deseado, etc. y cuyo error debe mantenerse dentro de unas tolerancias. Las operaciones exactas pueden variar dependiendo de las áreas protegidas durante la electroconformado, el tiempo de proceso y otros fenómenos estocásticos. A precise anode must also be constructed and used to ensure correct grain size and homogeneous deposition, without nodular growth of the metal surface. Once the elements to which electroconformado has been applied are housed, the assembly is machined again to ensure that the shape, dimensions and relative orientation of all parts are according to the original design parameters, precisely defined during the design process of the cavity and that depend on the type of beam, desired range of energies, etc. and whose error must remain within tolerances. Exact operations may vary depending on the protected areas during electroforming, process time and other stochastic phenomena.
Finalmente, el conjunto (1 ) se pule mecánicamente para mejorar la calidad de la rugosidad de la superficie, que es crítica para el rendimiento del tubo de deriva. Finally, the assembly (1) is mechanically polished to improve the quality of the surface roughness, which is critical for the performance of the drift tube.
En este texto, el término "comprende" y sus derivaciones (tal como "que comprende", etc.) no han de entenderse en un sentido excluyente, es decir, estos términos no han de interpretarse como que excluyen la posibilidad de que lo que se describe y define pueda incluir elementos, etapas, etc., adicionales. In this text, the term "comprises" and its derivations (such as "comprising", etc.) are not to be understood in an exclusive sense, that is, these terms are not to be construed as excluding the possibility that what described and defined may include additional elements, stages, etc.
Por otro lado, la invención no está limitada, evidentemente, a la(s) realización/realizaciones específica(s) descrita(s) en el presente documento, sino que también abarca cualquier variación que pueda considerar cualquier experto en la técnica (por ejemplo, por lo que respecta a la elección de materiales, las dimensiones, los componentes, la configuración, etc.), dentro del alcance general de la invención según se define en las reivindicaciones.
On the other hand, the invention is obviously not limited to the specific embodiment (s) described in this document, but also encompasses any variation that any person skilled in the art may consider (for example , as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention as defined in the claims.
Claims
REIVINDICACIONES
Procedimiento de fabricación de un tubo de deriva (1 ) de un acelerador lineal, que comprende las etapas de: Method of manufacturing a drift tube (1) of a linear accelerator, comprising the steps of:
a. proporcionar una tapa del tubo de deriva (2) compuesta por cobre electrolítico puro libre de oxígeno, to. provide a drift tube cover (2) composed of oxygen-free pure electrolytic copper,
b. insertar a presión la superficie de la tapa del tubo de deriva (2) en un núcleo del tubo de deriva (3) compuesto también por cobre electrolítico puro libre de oxígeno de modo que el contacto sea hermético, b. pressurize the surface of the drift tube cover (2) into a core of the drift tube (3) also composed of pure electrolytic oxygen-free copper so that the contact is airtight,
c. electrodepositar cobre sobre la junta, C. electrodeposit copper on the board,
d. formar así una tira de cobre de sellado continua (6) que rellena completamente los huecos entre el núcleo y la tapa del tubo de deriva.d. forming a continuous sealing copper strip (6) that completely fills the gaps between the core and the drift tube cover.
Procedimiento según la reivindicación 1 , que comprende además una etapa de proporcionar una ranura (4) en la superficie de la tapa en una posición que permita la deposición de cobre dentro de la ranura durante la etapa c. Procedimiento según cualquiera de las reivindicaciones anteriores, en el que el espesor de la tira de sellado es de 2-3 mm.
Method according to claim 1, further comprising a step of providing a groove (4) on the surface of the lid in a position that allows the deposition of copper within the groove during step c. Method according to any of the preceding claims, wherein the thickness of the sealing strip is 2-3 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/ES2010/070386 WO2011154563A1 (en) | 2010-06-09 | 2010-06-09 | Drift tube for linear accelerator (linac) with four-pole permanent magnets without welded caps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/ES2010/070386 WO2011154563A1 (en) | 2010-06-09 | 2010-06-09 | Drift tube for linear accelerator (linac) with four-pole permanent magnets without welded caps |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2011154563A1 true WO2011154563A1 (en) | 2011-12-15 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/ES2010/070386 WO2011154563A1 (en) | 2010-06-09 | 2010-06-09 | Drift tube for linear accelerator (linac) with four-pole permanent magnets without welded caps |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2011154563A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014099318A (en) * | 2012-11-14 | 2014-05-29 | Mitsubishi Heavy Ind Ltd | Manufacturing method of drift tube and drift tube |
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| WO2000028797A1 (en) * | 1998-11-05 | 2000-05-18 | International Isotopes, Inc. | Internally cooled linear accelerator and drift tubes |
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| US5021741A (en) * | 1990-04-12 | 1991-06-04 | Grumman Aerospace Corporation | Cast charged particle drift tube |
| US4993620A (en) * | 1990-05-03 | 1991-02-19 | Grumman Aerospace Corporation | Solder-electroformed joint for particle beam drift tubes |
| WO2000028797A1 (en) * | 1998-11-05 | 2000-05-18 | International Isotopes, Inc. | Internally cooled linear accelerator and drift tubes |
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| ILG T ET AL: "Mechanical design of the drift-tube Linac (DTL) for the Spallation neutron source", PROCEEDINGS OF THE 2003 PARTICLE ACCELERATOR CONFERENCE. PAC 2003. PORTLAND, OR, MAY 12 - 16, 2003; [PARTICLE ACCELERATOR CONFERENCE], NEW YORK, NY : IEEE, US, vol. 5, 12 May 2003 (2003-05-12), pages 2841 - 2843, XP010700176, ISBN: 978-0-7803-7738-7, DOI: DOI:10.1109/PAC.2003.1289739 * |
| YAMAZAKI Y ET AL: "DEVELOPMENT OF THE 1 GEV PROTON LINAC FOR THE JAPANESE HADRON FACILITY", ACCELERATOR SCIENCE AND TECHNOLOGY. CHICAGO, MAR. 20 - 23, 1989; [PROCEEDINGS OF THE PARTICLE ACCELERATOR CONFERENCE], NEW YORK, IEEE, US, vol. 2 OF 03, 20 March 1989 (1989-03-20), pages 947 - 949, XP000130406 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014099318A (en) * | 2012-11-14 | 2014-05-29 | Mitsubishi Heavy Ind Ltd | Manufacturing method of drift tube and drift tube |
| US9029796B2 (en) | 2012-11-14 | 2015-05-12 | Mitsubishi Heavy Industries, Ltd. | Drift tube manufacturing method and drift tube |
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