WO2005001020A2

WO2005001020A2 - A multi-stage open ion system in various topologies

Info

Publication number: WO2005001020A2
Application number: PCT/IL2004/000580
Authority: WO
Inventors: Doron Weinfeld
Original assignee: Axiomic Technologies Inc
Priority date: 2003-06-30
Filing date: 2004-06-30
Publication date: 2005-01-06
Also published as: IL156719A0; WO2005001020A3

Abstract

An open ion source embodied in a vessel having an accelerating voltage applied to at least one outlet. The source includes a supply of gas molecules. The source also includes at least one magnet for generating a magnetic field, at least one outlet of the vessel, wherein the opening is sufficiently wide for the ions to exit the vessel and an electron source at the same at least one outlet, wherein the electrons collide with the gas molecules to produce the ions, and the electrons form a space charge to focus the ions into a beam in order to facilitate their exiting through the at least one outlet. The electrons are launched, the ions leave and the magnetic lines begin at the point of the same at least one outlet, and the electrons stay on the magnetic lines from which they are launched.

Description

A MULTI-STAGE OPEN ION SYSTEM IN VARIOUS TOPOLOGIES

FIELD OF THE INVENTION

The present invention generally relates to ionization. More specifically, the present invention relates to a multi-stage open ion pump system, which uses a confined plasma under high vacuum and a unique injection of the ions, and relies on an invariant principle applied to a variety of topologies and geometries

BACKGROUND OF THE INVENTION

Reaching pressures far below atmospheric is a matter of capturing molecules one by one, of counting those that remain, and keeping others out. When pressure is reduced below atmospheric to 10^"6 mm of mercury, this is the region of high vacuum. Pump to still lower values, below 10^"9 mm Hg, and this is the region of ultrahigh vacuum. In these realms of relative nothingness, gas molecules are so far apart that their flow is determined by the probability of their collision with the walls of the vacuum system rather than with each other. This is known as a molecular region, wherein the vacuum system design depends on gas physics. Gas within the system emanates from the materials of the system and affects the pressure more than the original atmosphere being removed. This is known as outsourcing. Such sources of unwanted pressure lead to high costs for high-vacuum systems. In an open vacuum pump the gas evacuated from a chamber is directly transferred to the atmosphere outside, or is indirectly transferred through an additional open pump. Open pumps are always used in the higher-pressure range of 1 atmosphere (atm) to 10^"5 atm. At standard atmospheric pressure and temperature, there are approximately 7.5x10^"6 in. between collisions. As the pressure decreases, the density decreases and the mean free path increases linearly. Within the region of ultrahigh vacuum at a pressure of 10^'10 Torr, there are more than three million molecules/cc, the Torr being defined as 1/760 of a standard atmosphere. Yet on the average, a molecule will travel over 300 miles between collisions. In outer space, the pressure is estimated at around 10^"16 Torr. Thus, the density is about 3 molecules/cc, so the mean free path is in the order of the distance between the earth and the sun. The concept of the mean free path is extremely important for evacuating a confined space to very low pressure. The mean free path is defined as the average distance that a molecule will travel between collisions with another molecule. At atmospheric pressure, or low vacuum conditions, the mean free path is exceedingly small and the molecules are in a constant state of intercollision. Energy or momentum is transferred through the gas by means of this constant intercollision process. This region is known as the region of viscous flow. As the pressure is reduced, the mean free path increases. Eventually, the point is reached where the mean free path is equal to or greater than the dimensions of the confining chamber. Under this condition, the molecules will collide more frequently with the walls of the chamber than with each other, and the gas is said to be in molecular flow or a molecular regime. Ion pumping is used to remove gases from a system in order to create environments with ultrahigh vacuums. F. Penning (1937-Holland) developed a cold cathode ionization gauge for measuring pressures in the range of 10^"3 to 10^"5 Torr. A Phillip's Penning cell can operate up to 10^"10 Torr and has an efficiency of 0.5% or less, but has no focus and no exhaust. Due to the sputtering effect of the high voltage, ions were both buried in and "gettered" by the cathode material. Gettering is the chemical combination of active gases with a suitably reactive substance. In all the main approaches to plasma confinement, the principal measures of performance - plasma density; temperature; and confinement time - are improved by more than an order of magnitude as a result of intensified fusion research in the 1970's. The tokamak approach has already come within a modest factor of meeting the minimum plasma requirements for energy breakeven. A tokamak magnetic field, for example, has at least 3 to 7 Tesla (T). A plasma is basically a state of matter in which electrons are dissociated from their original partners: nuclei; molecules; etc., giving rise to a collection of charged particles of both signs, that interact strongly. The most usual plasma is a gas having an energy input, whereby the electrons are dissociated from the nuclei. The energy may come from heating the gas under high vacuum conditions, which is vital to many important applications, by radio frequency (RF), microwave, laser, Ohmic or other means. The energy may also come from electrons accelerated through an electric potential that crosses the gas. The first case involves a hot thermal plasma, while the second produces a cold plasma. The cold plasma region is considered to be from 0.005 to 1.0 T, i.e., from 50 Gauss to 10 kGauss. Scientists have long sought in vain to confine a cold plasma under high vacuum conditions, which is vital to many important applications.

All closed ion pumps devices operate in the same way. Gas molecules enter a field of high-speed electrons where some are subject to collisions. In the collision process, a molecule may lose one or more of its own electrons and thereby is left as a positively charged ion. Under the influence of a strong electric field, the ion is accelerated into the titanium cathode. The force of this collision is sufficient to cause very small particles, usually atoms, to be physically removed from the electrode and "sputtered" onto the adjacent waits of the pump. Noble gases like helium, neon, argon, krypton, and xenon are non-reactive. These are pumped by "ion burial," the "plasteringover" of inert gas atoms by the sputtered getter atoms.

The simplest and most common form of ion pump is the Penning cell, or a version of it. The Penning cell was originally conceived as a cold cathode vacuum gauge. It consists of a central anode unit upon which is imposed a positive voltage. Opposite each open end is placed a plate of titanium metal that is electrically connected to ground to form the cathode structure. A cell configured in this way is said to be a diode pump. It is then packaged in a suitable high vacuum container and the unit cell becomes a pump with a pump speed of about a liter per second. To make a higher speed pump, it is now simply a matter of making a package containing more cells. The result of this pumping action was a noticeable pressure reduction. The Penning call has been used as a commercially available vacuum gauge ever since, but it was not until the late 1950's that its pumping characteristics were exploited by Varian Associates, resulting in the invention of the ion pump. The invention of the sputter ion pump ushered in the era of ultrahigh vacuum, just in time to make a large contribution to the space age. The availability of vacuum systems that could routinely achieve pressures in the low 10^'11 Torr range enhanced R&D efforts. Due to its cleanliness, bakeability, lower power consumption, vibration-free operation, and long pumping life, the ion pump remains the choice of most who need to employ ultrahigh vacuum. Applications for these pumps are found in many areas such as: appendage pumps; auger electron spectroscopy; cryogenics; electron microscopes; electron spectroscopy for chemical analysis; electron tube manufacture; infrared and ultraviolet detectors; mass spectrometers; materials science, especially computer chip manufacturing; nuclear physics; outer space simulation and exploration; particle accelerators; secondary ion mass spectroscopy; superconducting transmission lines; and x-ray energy spectroscopy. When used with properly designed systems and hardware, the ion pump provides the ideal means for clean, low pressure, fail-safe pumping. Basic Performance Factors: Pump speed. As in the case of any high vacuum pump, pump speed is the main factor in determining the time it takes to attain the ultimate base pressure of a system. However, the ion pump pumps various gases at different rates - from very fast for hydrogen to quite slow for argon; so, it is necessary to check specifications to match the pump properly to the application. Maximum throughput. For ion pumps, it is measured in micron- liters/second rather than Torr-liters/second. Starting pressure is the pressure to which the ion pump must first be rough pumped before the glow discharge will be confined to the anode cell structure. To attempt to start the pump at higher pressures will eventually result in excessive heating and possible damage. Pump life is the time that the pump can be expected to retain a useful pumping speed and is related to the average operating pressure. Typically, at 10^"6. Ion pumps are larger and more reliable than any of the other types of pump, and have an 85% share of the ultra-high vacuum pump market. For increased effectiveness ion pumps need to generate a higher number of ions. The many different applications of vacuum in use today require a variety of operating pressures. When a high ion output over a wide range of pressures is achieved many opportunities exist.

Therefore, there is a need to provide an ion source and an ion pump, in various topologies and geometries, that confine a cold plasma under high vacuum conditions, which is vital to many important applications as described above.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide an ion source and an ion pump, in various topologies and geometries, that confine a cold plasma under high vacuum conditions, which is vital to many important applications. It is another principal object of the present invention to develop a system capable of delivering a focused ion beam over a wide range of pressures. It is a further principal object of the present invention that the ions get out of the system, but not the electrons. This is the concept of a valve. It is yet another principal object of the present invention that the ionization process be continuous, preferably achieving three orders of magnitude per stage. It is still another principal object of the present invention to confine a cold plasma. It is one more principal object of the present invention to induce a molecular flow regime, wherein the mean free path of the molecules is at least 5 times larger than a typical vessel size. The present invention discloses an open ion source embodied in a vessel having an accelerating voltage applied to at least one outlet. The source includes a supply of gas molecules. The source also includes at least one magnet for generating a magnetic field, at least one outlet of the vessel, wherein the opening is sufficiently wide for the ions to exit the vessel and an electron source at the same at least one outlet, wherein the electrons collide with the gas molecules to produce the ions and the electrons form a space charge to focus the ions into a beam in order to facilitate their exiting through the at least one outlet point. The electrons are launched, the ions leave and the magnetic lines begin at the point of the same at least one outlet, and the electrons stay on the magnetic lines from which they are launched

The ion source may be such that the electron source is a filament.

The ion source may be such that the opening for the at least one outlet is sufficiently narrow to cause the ions to form a plasma.

The ion source may further comprise a grid external to the vessel, wherein the grid has a negative voltage to keep the electrons inside vessel and to attract the ions out, wherein the grid has openings through which the ions can pass.

The ion source may further comprise a secondary outlet beyond said grid, wherein the grid is tilted in order to direct the ions through said secondary outlet.

The ion source may be such that the ions are focused before being directed through the secondary outlet.

The ion source may be such that the configuration is radial. The ion source may be such that the configuration is axial.

The ion source may be such that the source is used as an ion pump.

The ion source may be such that the source is used as an ion gauge to measure the density of the ions in the vessel.

The ion source may be such that the source is used for a spattering process.

The ion source may be such that the source is used for an ion implantation process. The ion source may be such that the source is used for a propulsion engine.

The ion source may be such that the source is used for a mass spectrometer by diverting said beam with a magnetic field, wherein said magnetic field serves as a mass discriminator. The ion source may be such that the source is used for a mass spectrometer by diverting said beam with a radio frequency field, wherein said radio frequency field serves as a mass discriminator.

The ion source may be such that the source functions at less than 3 Torr.

The ion source may be such that the source is used for a low energy ion source of less than 200 electron volts.

The ion source may be such that the source is used for nanotechnology purposes.

The ion source may be such that the nanotechnology is ion beam epitaxy (I BE).

The ion source may be such that the nanotechnology is nitrogen beam epitaxy (NBE).

The ion source may be such that the nanotechnology is oxygen beam epitaxy (OBE).

A method is disclosed for producing ions, wherein the source is embodied in a vessel having an accelerating voltage applied to at least one exit point, the method comprising: providing a supply of gas molecules, providing at least one magnet for generating a magnetic field, wherein there is at least one zero magnetic field line in the vessel; providing at least one primary outlet of the vessel at the same at least one exit point, wherein the opening for the at least one primary outlet is sufficiently wide for the ions to exit the vessel; and providing an electron source at the same at least one exit point, wherein the electrons collide with the gas molecules to produce the ions and the electrons form a space charge to focus the ions into a beam in order to facilitate their exiting through the at least one primary outlet point, such that_, the electrons are launched and the magnetic lines begin at the same at least one exit point, and the electrons stay on the lines from which they are launched, wherein the ions leave through the same at least one primary outlet.

The present invention discloses a method for a group of devices able to ionize a gas into plasma over a large range of pressures. In addition, during and after the ionization the ions are directed outside the system. Thus, a very efficient pumping method is obtained. This method can be utilized in a vacuum pump for a variety of applications. The method and devices involve a new approach for ionizing a gas into plasma and focusing and confining the plasma. This method is unknown in the prior art. The novel aspect is achieved by caging the electrons in a magnetic field having a special topology. This is done in combination with the use of electrostatic fields, which are almost closed, for caging the electrons for long periods of time, thus enabling the agglomeration of high electric charge in relation to known devices, by getting the ions to go through the outlet and converging them in a narrow stream by various mechanisms. This plasma is unique because the ions are maintained along the lines of the magnetic field on which they are created, and they are repelled through the outlet at a slow velocity. The efficiency of ionization depends on how much they are crowded. Thus, a relatively low voltage of only a few hundred volts is needed. The system creates electromagnetic fields during its operation, which vary in radio frequency (RF), and they enable very efficient transfer of the energy from the electrostatic field to the electron, thus heating them and enabling the efficiency in low voltage. The system uses sources active electrons that are "hidden" inside the magnetic field, and enable the flow of electrons into the system, with very few electrons escaping. In this way, with very low pressures, a very high concentration of electrons is obtained by preserving the longevity of the electrons inside the system. This electronic valve enables the making of plasma, while using a very weak source. The valve can also be used for other applications. The outlets enable only the ions to get out. This is

done by a combination of electrostatic and electromagnetic fields in a unique way. The valve prevents the return of the neutral molecules, by taking out the ions from the "outlet," and by ion optics convergence makes the outlet very narrow. Solar-electric, or ion propulsion engines, for example, use electrons generated by solar panels to strip xenon atoms of one electron. The positively charged xenon ions are then pushed out of the chamber in a continuous stream. Physics conservation laws stipulate that if the ions go out one way, the spacecraft goes the other. The power is nothing compared to a conventional rocket, but over time a spacecraft can be propelled to significant speeds at tremendous cost savings. E.g., when launch is from the space station, and away from the gravity of earth, immediate power is not needed. Thus, solar electric ion propulsion allows a much heavier payload.

Other features and advantages of the invention will become apparent from the following drawings and description.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, in which like numerals designate corresponding elements or sections throughout, and in which:

Fig. 1 is a z-r cut-away view schematic illustration of the major components of an exemplary radial ion system, constructed and operated in accordance with the principles of the present invention; Fig. 2 is a z-r cut-away view of the permanent magnets, electromagnets and the associated magnetic field lines in an exemplary radial ion pump, constructed and operated in accordance with the principles of the present invention; Fig. 3 is a z-r cut-away view of the electron distribution in an exemplary radial ion pump, constructed and operated in accordance with the principles of the present invention; Fig. 4 is a z-r cut-away view of the plasma space for argon ions in an exemplary ion pump, constructed and operated in accordance with the principles of the present invention; Fig. 5 is a z-r cut-away view schematic illustration of the major components of an exemplary ion gauge, constructed and operated in accordance with the principles of the present invention; Fig. 6 is a schematic illustration of a one-stage axial pump, constructed in accordance with the principles of one preferred embodiment of the present invention; Fig. 7 is a computer screenshot of a magnetic simulation of the axial ion pump, constructed in accordance with the principles of one preferred embodiment of the present invention; Fig. 8 is a schematic illustration of the rods comprising the electron source, constructed in accordance with the principles of one preferred embodiment of the present invention; and Fig. 9 is a schematic illustration of a one-stage axial pump having two outlets, constructed in accordance with the principles of one preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The method relates to a group of devices able to ionize a gas over a large range of pressures. During and after the ionization, the ions are directed outside the system. Thus, a very efficient pumping method is achieved, and can be utilized for a vacuum pump for a variety of purposes. The inventive method and system are now described for ionizing a gas and focusing the ions. The novelty is derived from caging the electrons in a magnetic field having a special topology. The magnetic field is applied in combination with a nearly closed electrostatic field for caging the electrons over a long period of time. This enables agglomeration of a previously unachievable high concentration of electric charge. The ions are output and focused into a narrow stream by using various means. A novel feature of the system is that the plasma ions are confined to the lines of magnetic force along which they are created, and are repelled outside at a slow velocity. This velocity depends on how tightly they are focused. The very high ionization efficiency requires only a relatively low voltage of a few hundred volts. During operation the system creates variable electromagnetic radio frequencies (RF), which enables the high efficiency by heating the electrons. The system uses sources of electrons that are "hidden" inside the magnetic field, enabling the flow of electrons within the system, with near zero leakage. Thus a high concentration of electrons is obtained at very low pressure, and also preserves the longevity of the electrons inside the system. This electronic valve induces plasma from a relatively weak source, and can be used for other applications. The valve prevents the neutral molecules from returning to the system by taking the ions out through the outlet. Making the outlet very narrow does this. A few of the ions then proceed away from the outlet. Prior art uses ion optics for this purpose. By contrast, the present invention uses "neutral optics." I.e., collisions with the wall are used to predict the chance of arriving at a particular place according to the cosine-squared law. When energy is higher, and reflection is off a "flat" surface, specula reflection light can be utilized because there is a higher component of movement away from the outlet. The cosine-squared law depends on the energy with which a particle hits the wall. Thus, the ions are 1000 times more likely to remain outside the pump and not return. Inside the pump there is a low vacuum at 3 x 10^"6 Torr, while outside the pump there is a relatively higher vacuum of about 10^"3Torr. The aim is for a low probability of return, or backflow by having the ions spend more time under the higher pressure. According to simulation studies, the probability of a factor of one thousand is achievable before the ion returns. The pressure difference is calculated from Boyle's Law: pV = nkT. Adding stages can increase the vacuum. Each stage has the same factor of 1000. So two stages provide a compression ratio factor of one million, and three stages provide a factor of one billion. There are two ways to achieve low backflow. First, the outlet can be made narrower. Second, the ion path outside the pump can be increased as much as possible. By applying the combined electromagnetic and electrostatic fields the outlets are designed to enable the ions to get out, but not the electrons. The average kinetic energy is 26.5 electron volts (eV), for an input, depending on the size and pressure. The voltage is 100 to 400 volts, compared to the prior art use of 30 to 70 eV. The quantum efficiency is the proportion of the ion energy output to the energy input. The quantum efficiency is improved over the prior art by greater than a factor of 20. This is especially significant at high pressure. E.g. to get 1 ampere ion current at 10^"3Torr, 1 kv or I kwatt must be the input for the prior art. Such power would evaporate the inside of the pump. Neutral molecules, of inert argon gas, for example, require a relatively much longer time to return back. This time ratio can be 1000 or more. The pressure difference between the outlet and inlet can be derived from this time ratio. To get even deeper pumping a few stages are combined in one chamber. It is important that a succeeding stage be only a few percent of the previous stage, but in reality about 20% of the first stage in volume, e.g., between 15 cm to 18 cm for a 300 liter/second pump. The pump can deal with every gas including corrosive gases, because the internal surface can be any metal, such as titanium or tantalum, which can withstand corrosion extremely well. The pump can also handle noble gases, such as helium, because all of them can be ionized. The acceleration voltage of the electrons (e^"'s) can determine their temperature, i.e. energy. Therefore, using an optimum gas temperature the ionization rate for each gas can be maximized. This can be done automatically by use of feedback control to find the voltage that gives the maximum output current. The ion current on the outlet can be translated linearly by multiplying by the factor 0.1777 liter per second by the amps/Torr. E.g., 1 amp/Torr gives 0.1777 liter/sec and -3 Torr gives 177 liter/sec.

A molecular flow region is induced, wherein the mean free path of the molecules is at least 5 times larger than a typical vessel size, i.e. having a radius of 5 cm and a length of 12 cm. Typical vacuums for given radii are: Torr 10^"3 at 5 cm; and Torr 10^~5 at 500 cm. The present invention discloses a method of inducing plasma ionization of residual gases, focusing the ions by applying the distribution of the space charge and pumping them outside the system by ion optics. This process is applied over a short distance, independent of the initial conditions of the ions, such as their mass, velocity and starting location. After output of the ions from the opening of the main chamber, the ions are channeled for a substantial distance. The succeeding stage is in the form of a backup pump. This can achieve high- pressure differences between the entrance and the exit. Thus, the system actually functions as a molecular valve. This is an innovative process. The plasma technique is highly efficient because of five innovative factors. The system is based on the confinement of electrons inside a nearly closed magnetic field, which has a few openings that are open magnetically, but closed electrostatically. The ions are confined inside the closed electrostatic field, except for the exit opening in a way that allows accumulation of space charge. The charge density is a few orders of magnitude higher than the penning cell. An active electron source, for example, a filament, is located in one of the openings of the magnetic field in a way that allows entrance of electrons in a parallel direction to the magnetic field. When an electron wants to return, it is stopped (1 ) by the electrostatic field and (2) by the way it returns. The electron usually returns with a different angular momentum with respect to the specific line of the magnetic field where it emanated. The result of this is called the magnetic bottle effect. The electrostatic field, using very low voltages, does the transfer of energy to the electrons, because the electrons themselves create an RF field that exists with a natural feedback, which depends on the geometry, the magnetic field and electrostatic field. As a result there is an extra benefit, wherein the lifetime of the ions can last for a few tenths of a second. This allows keeping electrons in the system for longer times. Therefore, the plasma density is much higher and it surpasses the 10% in lower pressure systems, such as 10^"6 Torr and lower. Ten percent means the number of ions is 10 % of the number of neutral particles. Also the ions are not homogeneous in all of the space of the pump, but exist only in a certain geometry that is a function of the shape of the magnetic field in relation to the electric field. In this way it is possible to determine how many ions are created, and also the initial conditions such as the initial velocity. In the area of the creation of the ions the ions repel each other and exit in a diffusive manner toward the openings that have been set for that purpose. There is dependence between the mechanical opening, the magnetic field and the accelerating voltage on the electrons and the ions. The special equilibrium between these forces allows the exit of the ions from the vessel through a narrow opening. When the ions exit through the central opening, they pass through the electrostatic field alone toward the secondary opening. As the distance between the primary opening and the second opening becomes greater, the path is more winding and narrower. This makes it more difficult for the molecular ions to return to the main chamber. The typical time for the return is the thermal velocity divided by the average effective distance, which is V_n / U. The compression rate of the valve is proportional to the ratio of time that it takes an ion to arrive at the secondary opening, relative to the time that it takes a neutral molecule to return to the primary opening. The size of the vessel relates to the compression rate. Very large differences in compression are achievable, but three orders of magnitude are commonly attained. All the computations are correct for pressures where the mean free path is less than the vessel size. The topology of the magnetic field is not connected in a simple way. I.e., there are areas where the field lines inside the main chamber are not connected to one another, but end inside the magnets, i.e., either the permanent magnets or the electromagnets. Thus, an electron that is created in a certain area cannot leave the magnetic line on which it was created. Connections between the different areas of the field are perpendicular to the field lines, and do not allow the passage of electrons through this magnetic block. Thus, it is possible to build a field that is very low in the middle compared to its size, just like a bottle. It is vacant inside, but it also has magnetic walls and a few openings that are closed by electrostatic fields.

Fig. 1 is a z-r cut-away view schematic illustration of the major components of an exemplary radial embodiment of ion pump 100. Inert argon gas molecules 105 in a source chamber 110 enter an ionization vessel 120. The ions 115 thereupon created will exit ionization vessel 120 at primary outlets 130, which are gaps in the electromagnet 135, and then traverse a grid 140. A percentage of ions leave ion pump 100 through a secondary outlet 150, preferably in the form of a focused beam.

Fig. 2 is a z-r cut-away view of the electromagnets and the permanent magnets 221 , 222, 223, 224, 225 and 226, and the magnetic field lines of the associated magnetic field for ion pump 100. Polar coordinates are used having an r-axis 201 and a z-axis 202. Permanent magnets 221-226 have a polarity as shown. Fig. 2 shows lines simulating the shape of the magnetic field. The magnetic field causes the electrons to move freely in the center of the space and to climb very close to its entrance 230, but they cannot pass through the electric field and exit their space. The electron distribution is shown in Fig. 3 below. The areas where the electrons stay determine the space where the ions are created. This example is only one of many possibilities that can also be scaled or deformed, and still be used as a pumping mechanism, in the simplest embodiment there would be only three lengthwise magnets instead of four 221-224, and only two lengthwise sign changes instead of three. This configuration of magnetic fields is unknown in prior art, and scientists have long sought to confine a cold plasma. This configuration is an example of a related "family" of configurations, and can only be achieved in a non-simple topology. The electrostatic field is a result of voltage on the walls 240 of vessel 120 and on the filaments 250. Filaments 250 in each primary outlet 130, of which only one such pairing is marked in Fig.2, are the source of electrons. There are two filaments 250 in this exemplary embodiment, although one would still function. Electrons are injected into the system and create a negative potential in the areas where they are concentrated. Thus, negative potential is created on grid 140 relative to vessel walls 240, and takes on the shape and intensity of the magnetic field. The steel components are composed of feral magnetic material, for example 1010 steel. The fields inside vessel 120 are the fields used. Different zones of the field are designated 260 through 265. Zone 261 designates no magnetic field or a very low magnetic field, which can reach a few gauss. The relatively magnetized zones are designated zone 262. Zone 263 is close to the magnets and can be 10-80 times stronger than zone 261. In zone 263 the magnetic field lines are substantially parallel to a magnet. This works as a magnetic wall and doesn't allow electrons to pass. The "Z" component of the magnetic field changes direction when it goes through any outlet 130. The electrons stay inside and are confined to the lines needed to sustain the ionization process. The ions are produced by collisions between the electrons and the argon gas, wherein an electron is emitted and the gas ions can be output, as shown by typical ion path 270 through secondary outlet 150.

A magnetic field line designated 260 is a specific line of zero magnetic field. Electrons will accumulate at lines 260 and draw the ions created nearby to them so that in the end they will get out by following line 260 through a primary outlet 130. On the side are small ring magnets 225 and 226. These create circular fields 264, which don't allow electrons to approach. This is called the "bottle effect" or "mirror effect." Most electrons have high angular momentum due to the launching mechanism, and therefore can't pass these points. The result can be seen in Fig. 3 hereinbelow. In the external zone 265, the magnetic field is almost zero, and is especially designed to prevent discharge when the pressure becomes high. Such discharge is called the corona effect, and is characterized by sparks. In summary, the foregoing describes the configured shape of the magnetic field. This is one of a family of shapes characterized by having a defined, non-simple topology. For example, the magnetic field lines are never closed inside the pump, nor are they toroidal in shape. Also, there cannot be a line that traverses pump 100, neither vertically nor along the length of the pump along z-axis 201. Lengthwise traversal would require several sign changes. In Fig. 2, the field changes polarity four times because there are four internal magnets 221-224, aside from the two outside ring magnets 225 and 226. The invention requires at least two magnets and two polarity changes. The magnetic field in zone 261 , the heart of ion pump 100 along the z-axis 201, is always low. This phenomenon is used to help launch electrons and accumulate them there as in a real "bottle." In Fig. 2, there are three primary outlets 130. Every variation in the magnetic rings 222a, 222b and 222c comprising magnet 222, for example, changes the shape of the magnetic field, e.g., the angle, the diameter, etc. The system works, in any case, so long as the basic field structure is empty on the outside in zone 265, but strong at the walls and has a few primary outlets 130, wherein outlets 130 represent points of leakage, i.e. non- confinement. This is an important inventive step because industry and academia have never used it to create a plasma, and especially for using this effect to focus the plasma for output. The three inventive components are the magnetic field, filament 250 and a launching mechanism that uses a zero magnetic field inside and a space charge as a focusing mechanism, especially at low pressures of -4 Torr or less. If primary outlet 130 is too wide there can be no plasma. If primary outlet 130 is too small the ions don't get out. The ions try to stay near the electrons because they are attracted to the space charge. This helps to focus the ions before extraction. Grid 140 is tilted with a horizontal component towards the main outlet. The use of a negative voltage keeps the electrons in, and draws the ions out. This is called an electron valve. In an alternate embodiment the system described is used for a closed ion source, wherein there is no secondary outlet and the ions are kept inside ionization vessel 120. A closed ion source is used for a low pressure environment. The magnetic lines progress from a narrow place, i.e. primary outlets 130, and expand inside. This is where the electrons must be launched and they must stay on the same line from which they are launched. Primary outlets 130 are where the lines converge or begin. There must be a filament 140 and a primary outlet 130. The overall system is exemplified as an ion pump 100 or an exhaust pump. It is essential that primary outlet 130, filament 140 and the accelerating voltage all be at the same point. An effective plasma system requires a wide range of pressures. Radial ion pump 100 has a 2-3% efficiency at 100-400 volts, depending on the scale and pressure, compared to about 0.5% for the prior art. The quantum efficiency is 10 nanoseconds per voltage input. Greater than 20 is important for high vacuum. One kilowatt will evaporate the material. The present invention uses .01 watt. The primary applications of the ion system can be differentiated as follows: when it focuses to a small point at secondary outlet 150, it's an ion source; and when there's an exhaust from outlet 150, this is an ion pump 100. All types of magnetic material can be used. This material determines the power of the flux lines of the magnetic field. Fine-tuning and fine focus are optional refinements.

Fig. 3 is a z-r cut-away view of the electron distribution 300 in an exemplary radial ion pump, constructed and operated in accordance with the principles of the present invention.

The negative potential in electron distribution 300 can reach hundreds of volts. Ions that are created as a result of electron bombardment are forced to remain at that potential, and are drawn to the most negative area, which is the exit zone of primary outlets 130. Magnets 221-226 and magnetic field zones 261-265 are the same as Fig. 2. In zone 263 the field is strong and parallel to the vessel lines. In this case the electrons get out by means of three filaments 250 located at primary outlets 130. A heating problem is preferably accommodated by use of copper heating extraction materials, for example, so the magnetic field won't be affected by overheating in the magnets. In order to reduce the quantity of the neutral molecules that return through primary outlet 130, the opening is reduced in size as much as possible. Therefore, the ions are focused into a small beam by the following means: the magnetic opening is narrowed, such that a narrow space charge is created having the same proportions as primary outlet 130; and a voltage is induced at primary outlets 130 by grid 140 or by magnets 225 and 226, which are in the form of rings, or by a combination of these, causing the ions to concentrate at the focus point. The width of the focus point is determined by different physical parameters, e.g. the initial velocity, and the geometric shape of the magnetic and electrostatic fields.

Fig. 4 is a z-r cut-away view of the plasma space for argon ions 400 in an exemplary radial ion pump, constructed and operated in accordance with the principles of the present invention. Fig. 4 shows a distribution of argon ions in space. Magnets 221-226 and magnetic field zones 261 -265 are the same as Fig. 2. In zone 263 the field is strong and parallel to the vessel lines.

Back pressure is 1 x 10^"5 Torr, i.e., a low vacuum. The speed of the ions is very high. The ions travel at least five meters before a collision occurs. The system is 12 centimeters in length. This is called a collision-less flow. Collisions only occur with the walls. The drift is fast, i.e., 20 - 40,000 m/sec at the outlet. The inside drift is 10% of this. Therefore, the ions remain inside for a long time, thereby helping to build the plasma. An electrostatic field is applied by means of a grid with openings so the ions can pass through without being reflected back. In the Penning cell only about one tenth of a second at low pressure coupled electron stays inside. By contrast, the present invention is the key to creating a plasma. If the opening is too great there is no plasma. If the opening is too small the ions don't get out. The ions try to stay near the electrons because they are attracted to the space charge. This helps to focus the ions before extraction. The grid is tilted with a horizontal component towards a main (exhaust) outlet. The use of a negative voltage keeps the electrons in and draws the ion out. This is also called an electron valve.

Fig. 5 is a z-r cut-away view schematic illustration of the major components of an exemplary ion gauge 500, constructed and operated in accordance with the principles of the present invention. The ion gauge acts like a small pump with no outlet. The principal object of the ion gauge of the present invention is higher sensitivity and smaller size. The effect of the ionization within the gauge is measure pressures of -4 Torr and less. Gas molecules 505 enter ion gauge 500 through 4-inch inlet 510. A cylindrical magnet 520 and a series of collectors 530 are configured around the axis 505 of ion gauge 500, which typically is a closed chamber. A pair of axial magnets 525 and a pair of filaments 540 are positioned along axis 550 as shown. The turbo is an evacuation pump used at one ampere and 0.177 liter/sec/Torr

(multiplied by 10,000 =1770 liters/sec). For high vacuum, a turbo pump is used. Tantalum aluminum nitrite is very popular. Also a roughing pump or backing pump gets to -2 or -3

Torrs. Beyond -3 is called "high vacuum". After the ions pass the main outlet, they can be drifted to the side by using grids or other electrostatic poles, and thereby they are drawn to the secondary outlet, which is the connection to the backup pump. The main method for doing this without losing too many ions is by having a negative potential associated with a grid. Ions are attracted to this grid, whatever the grid shape is, and try to bombard it because the grid is more than 90% free space. Only about 10% of the ions will collide with the grid and be neutralized. Out of this, 10% get out, but most go back.

A flow meter is used for measurement. E.g., about 70 molecules/sec get out of 100, from within the free 10%, and 30 molecules/sec go back. In order to get a lower pressure such devices should preferably be combined serially.

The first stage is at least 10 times larger than the second stage, because gas is already compressed by a factor of 10 x or more. The goal is at least a 1000-fold compression ratio between the input and the output. The second stage cost is almost negligible and staging is easily accomplished. The same power supply is used, and needs a separate voltage port.

Sixteen or 24 voltage ports can be tapped from a single voltage controlled secondary voltage card. The second stage can be a 5 cm extension to the first stage, which may be 20 cm, and the same magnets are preferably used for both stages, wherein the outer magnet is a hollow cylinder. If there are two pump stages, and each pump achieves a 1000-fold compression, there is a total pressure gradient of 1 ,000,000. This is approximately the amount needed for a turbo pump or a cryogenic pump. The maximum pumping ability may be three stages. To overcome this limit, the ion pump is best for ultra high vacuum. For every gas, one can change the electron temperature, i.e., the average kinetic energy of the electrons by changing the main voltage that accelerated the electrons. Thus the right electron energy can be found for maximum ionization. E.g., for nitrogen 70 e-volts is used, and for neon, which is preferred for ionization, 120 e-volts are needed. In this way the rate of ionization is not significantly different for different gases. The pumping speed also introduces some discrimination because of the differences in masses. This is done automatically by feedback loop control. I.e., by measuring the outlet current, and, if necessary increasing it by changing the voltage for optimal effect. The ions can be used for a mass spectrometer by diverting the beam with a magnetic field or an RF field, wherein either of these fields functions as a mass discriminator. The electrostatic field, however, is not a mass discriminator. Changing the electron current source changes the pumping speed without changing the electron temperature. Thus, the pump can be used as a valve or simply as a controller of pressure. There is no need to add a gas or rotor valve. This would shut down the pumping speed of the turbo, because it simply closes the valve. In this way a lot of ions can be trapped in a very unusual path, and only lose a few tenths of a percent. The pump can also be used to control vacuum pressure. The device has no moving parts, therefore it is very reliable and very easily engineered. Any metal can be used, therefore light metals and those with no chemical reaction are preferred. Titanium oxide is preferable, for example because it is both light and highly corrosion resistant. Magnetic field sources are either a permanent magnet or an electromagnet. Rare earth materials such as Ferrite, Sm2Co17 and NdFeB can be used for the electromagnet The pump preferably includes a controller that can handle many, if not all of its functions, such as pump speed and electron temp and shut-off. Shut-off is preferably automatic when a major problem arises, such serious leakage, filament problems or fire.

In an alternative, and generally preferable, embodiment, an axial pump having its exit or exits directly on the vertical axis will now be described. This is in contrast to the previously described radial pump embodiment with one, two or three exits, for example, which emanate radially from the vertical axis of the same basic cylindrical shape.

With reference to Fig. 1, corresponding to the radial pump, the plasma evolves in the space of the pump, and the electrons move along the lines of the magnetic fields generated in roughly spherical and hemispherical form as shown in Fig. 7. At the edges of these magnetic fields, there exists a negative potential of a few hundred volts, which deters the electrons from leaking out. At other parts of the pump, the electrons cannot escape due to the magnetic field. Ions are generated by collisions of electrons with gas molecules. The positive ions are held by the negative potential created by the space charge of the electrons. At the edges the ions are drawn out by the same negative potential that repelled the electrons.

Fig. 6 is a schematic illustration of a one-stage axial pump 600, constructed in accordance with the principles of one preferred embodiment of the present invention. In the axial pump system the focusing of the ions is enabled by the space charge and the negative charge at the edges, providing the opportunity to achieve a higher current by designing a small aperture. For example, a coherent positive ion plasma 610 has been achieved using an electron current of 300 milliamps, at a pressure of 10^"4 Torr, wherein the ion flow is directed through an outlet opening 620 of less than 6 mm in diameter. This obviously increases the compression ratio relationship of the pump, according to the compression ratio equation wherein:

Pi is the initial pressure in Torr; P_f is the final, or maximum, pressure in Torr. S is the area of outlet opening 620 in cm²; l_out is the ion current that exits the pump; P_in is the pressure at the inlet in Torr; P_out is the pressure at the outlet in Torr; R is the compression ratio, where R = P P ; F₀ut is the flow from inside to outside the pump through the outlet in units of Liters/(seconds/Torr); and F ac = 9.1^* S^*P_0Ut / Pin! ■^"net ^— r₀ut " "^"back >

The two relevant equations are given as:

I. F_ne, = 0.177* P_in - 9.1* S*P_0Ut / P,_n, such that F_net = 0 occurs when the pump stops pumping at this balance point; wherein

II. R = 0.0135* l_out / P_f*S, when P_in= P ; when, for example: . lout = 0.3 amp; P_f = 10^"4 Torr; and S = ττ*(0.3)² = 0.28, R = 143.2.

The equations are valid for a temperature of 300°K. For an outlet opening of 1 cm² there is a gas flow of 9.1 ^*S liter/(sec^*Torr). This is derived from the law of ideal gases, which is very accurate at this range of values. The equation is valid when the volume is measured at a given pressure. When the pressure increases by tenfold on one side of the pump, the gas flow on the other side will increase proportionally to 9.1* P_f / P, *S. In order to translate liter/sec, the value of 0.177 liter/sec. = 1 amp/Torr is placed in the equation, resulting in a value of 0.177. Thus, the compression ratio above is multiplied by

143.2. Fig. 9, for example, described hereinbelow, shows a pump with two exits. The air enters from the center in this type of pump, which is twice as efficient, but its geometry is less functional. The same principle applies to the axial pump as for the radial model. In this mechanism the exit point of the ions, the electron source 630 and the magnetic field lines are all at the same place. The more concentrated the magnetic field lines, the better the focus. Furthermore, in a preferred embodiment, electron source 630, the cathode/collector 640 and both the outlet magnet 650 and one end of the permanent magnet 655 all comprise an integral unit, which also affects the focus and creation of the plasma. Nuclear electrons, i.e., those captured in the magnetic field, create the same weak plasma as does the prior art Penning cell, but the electrons are energetic enough to heat the electron source to a point that electrons start to be released. This catalyzes an increase in the plasma until it achieves a steady state. That is to say, the current times the voltage creates enough output power to heat the tips of the electron source rods, enabling them to release more electrons in every collision with ions, relative to the number released in the cold state. This process continues to increase exponentially until a steady state is achieved where the space charge prevents more electrons from being released from the source, even though many more could be released at that temperature. The source can be initiated by direct heating or with an electron gun. The plasma 610 takes up only a small part of the cylindrical vessel 660. Thus, the ions cannot escape vessel 660 because the potential of plasma 610 is less than the surrounding space, due to electrons that are forced towards plasma 610 by the potential of electron source 630. Outside outlet opening 620 there is a deflector, either in the case of a single exit or for an optional additional source. For an additional source the potential is similar to the first source. This feature provides the effect of an electrostatic valve that prevents the electrons from exiting from the magnetic field on the other side of outlet opening 620. At this stage plasma 610 is extremely dense and hot because of energetic electrons that constantly flow from electron source 630. The slower electrons return to the cathode/collector 640, which is at the same location as electron source 630. Therefore it is possible to sufficiently ionize any inert gas, even helium, which is the hardest gas to ionize. For helium at 21 eV, a much higher current is reached than that of plasma developed in air, which comprises primarily oxygen and nitrogen. Because the mass of helium is lower, and the current is proportional to 1/VnT, the ionization conditions are effectively the same. Near the electron source 630, the high density of electrons in plasma 610 in the center of cylindrical vessel 660 causes the ions to be focused towards the very small opening of outlet 620, as mentioned above. Such a dense plasma at these pressures is unknown in the art. Furthermore, a plasma has never been achieved at this voltage at the low pressure of 1^*10^"5 Torr. The plasma is so dense because the ions spend a long time, approximately an average of 30 - 50 milliseconds, within the plasma before they exit the system and are neutralized. As a result electrons can stay in the system for a similar amount of time before exiting. For this reason the plasma density is at least doubled. This method has restrictions at low pressure, when in the area of 10^"6 Torr and lower. The average time of stay, i.e., the life span in the system is not substantial enough to create a new electron by ionization or by collision of ions with the cathode and maintaining its heat, thus causing the system to shut off. In order to avoid this phenomena there are a few solutions: expansion of the apparatus or the plasma such that the ion will spend more time in the system whereby its life span increases; use of materials with low work potential in the cathode pods so that less heat or less ion bombardment is needed to supply the same amount of electrons; increasing the potential in a way that the electric capacity of the pump times V, the voltage will increase the negative charge (CV=Q) that the pump can hold. To wit, in this case the plasma will be even more negative, with a higher surplus of electrons; their capture is due to the load created on the electronically loaded conductor; an a more efficient alternative is application of a special heater to the cathode to accelerate the electrons and lengthen their mean lifetime. A uniquely shaped magnet is used to prevent the ions from reaching the electron source. Two basic shapes have been described herein: one radial with reference to Figs. 1-4, and the other axial with reference to Figs. 5-6.

These methods have their restrictions when rising to currents of 10 k volts and above is not preferred. Thus an alternative approach has been developed. In this method a "Active" gas is created by metal vapor or any other material, which is conductive or semi conductive, that is heated by ion bombardment. The material is chosen so that its sticking probability, i.e., its probability of connecting/sticking to the walls is relatively small, resulting in a pressure in the range of 2-3 10*^"6 Torr. In this way metal molecules stay for a time substantial enough to be ionized and maintain a powerful plasma. This plasma contains mostly molecules of metal, but also maintains the electrons in it. These electrons not only ionize the metal molecules, but also the rest of the gases and all the positive ions are driven by the potential of the plasma, as described above, towards the collector stationed outside the pump. On the collector they are neutralized, thereby losing their kinetic energy, and after a few collisions with the walls, they stick to it. In order to achieve better vaporization pressure and prevent sticking to the walls, a material with a low probability of sticking with the vaporized material can be used to cover the walls or to construct the walls themselves. Heating the walls of vacuum vessel 660 to 60°C, and above, substantially prevents sticking The plasma etches the electron source. It is easy to calculate the life span of the electron source. For example: 1cc of carbon graphite fiber can last for six months, thus maintenance is extremely low; metal vapor is not problematic for the user, as is oil vapor in a diffusion pump, since leakage into the pumping system is minor for the following reasons: the vapor pressure is very low in comparison to the oil typically used in a diffusion pump, by a factor of 100,000 and more; their sticking ratio is high in comparison to the silicon oil used in a diffusion pump, by a factor of at least 1 ,000; and once they stick to walls they integrate with near zero chance of disconnecting.

This makes the pump highly suitable for high vacuum and ultra-high vacuum (UHV), where an oil free surrounding is needed. As mentioned above most of the focusing is achieved by the plasma space charge, and that is the reason that such high focus can be reached in such short length. The focus is achieved by the fact that the magnetic field lines concentrate in a small point in the diameter of a few mm. The closer to the middle of the pump, the more the magnetic field lines open up, and the volume of the plasma grows as a square function.

Fig. 7 is a computer screenshot of a magnetic simulation of the axial ion pump, constructed in accordance with the principles of one preferred embodiment of the present invention. Outlet magnet 650 and one end of permanent magnet 655 are again shown, and have the same general shape and juxtaposition as in Fig. 6. Outlet magnet 650 and an inlet magnet 720 are shown positioned adjacent to axial axis 710. The ions are created with kinetic energy near to zero/thermal. Thus, from the onset of their creation they are flowing in a direction set by the potential of the plasma. The potential of the plasma is a function of the concentration of the electrons within it, and this depends on the density of the magnetic field, which is very strong in the exit. Thus the electrons are drawn close to the source, which is also the exit, and the area having the densest magnetic field. This area also has the most negative potential, thus channeling the ions there. This approach is innovative in that it creates an electrostatic lens for ions. It creates a static potential in a 3D scope, thus enabling to development of a lens for the ions because of their high mass. Thus in an area/scope, empty from materials, a lens is created which cannot be made by simply using electrodes. The utilization of the lens is optimal for grids or rings that cause some of the ions to be lost, or to not be used. Furthermore, because of the cylindrical symmetry, the motion of the ions is not affected by their mass or by their potential, apart from a slight effect directly from the magnetic field. After the initial focus by the mechanism of the space charge, an additional focus takes place enabling the reduction of the exit hole. This focus mechanism is obtained by the voltage of the cathode in relation to the exit hole. The shape of the cathode also determines the shape of the focus, for example a cone shape or a narrow tubule. Once the ions have passed the outlet opening, it is very important to keep them from returning. For this reason the cathode/collector is cone shaped. An ion that hits the cone, initially "takes" an electron and becomes neutral, and then is pushed away at random, according to the cosine law. The largest probability is for perpendicular movement. As described in the pump figure, the volume is relatively large, and the molecules lose their energy after a few collisions with the walls. While the probability of exiting through the outlet opening is at least as high as the ratio between the exit of the pump and the exit hole of the flange. In an exemplary model, the outlet opening is 6mm in diameter, the exit flange is 48mm in diameter and thus the exit ratio is the square of the ratio, i.e., it is 64. There are many other factors that can affect the compression ratio relative to the exit hole, for example the size of the vessel that contains the collector. The larger the vessel, the longer the molecule will spend in it, thus decreasing the chance of it flowing out. In a very large vessel the ratio can reach the ratio of the exit. Thus, a pump that pumped by a factor of 100, according to the explanation above, will have another factor, that of the size of the vessel and the ratio between them. In the example above the compression ratio will reach 6400. By extending the distance that ions travel after exiting, the compression ratio would rise because the velocity of an ion varies as the square of the velocity of a neutral molecule on the way back. To wit, the pressure in the exit hole decreases according to the time of the return of a neutral molecule to the exit in comparison to the time of exiting to the next pump. This ratio is parallel to the probability of a molecule reaching the entrance compared to its probability to exit. In a length of a meter this ratio can add two orders of magnitude, but the technical implementation is very costly. The lighter the gas, the faster is its return velocity. I.e., the return velocity is proportional to the square root of the mass. Thus, the compression ratio is weaker for lighter gases. On the other hand, the ion current grows for the same reason, and by the same ratio. Thus, the compression ratio for all gases, both heavy and light, remains nearly the same. The one stage axial pump can easily be expanded to multiple exits. This can be done by constructing a multi-exit magnetic field (see Fig. 9 Multi-exit magnetic field). It is easier to build than the single exit model or the double exit model because there is no need to place additional magnets along the pump to support the magnetic fields in the center. All that is needed is a matrix of magnets and an entrance hole located in the center of the pump. Its efficiency in comparison to its volume is increased at least fivefold, which implies a substantial reduction in cost, as well as compactness. This provides a unique answer for many applications, such as ultra-high vacuum (UHV) portable pumps. It is possible to connect two or more apparatus in a serial manner to construct a single system with a single power supply and a single magnetic field even though it might be easier to separate them, but either approach is feasible. The size of the inventive system is smaller and the reliability is greater than any in the prior art. Also the shock resistant feature is new to the art. This breakthrough can change and help whole industries that until today avoided the use of vacuum technology.

Fig. 8 is a schematic illustration of the rods comprising the electron source, constructed in accordance with the principles of one preferred embodiment of the present invention. As mentioned above, the electron source has to be placed in the exit which is the same place where the magnetic field lines 810 concentrate. At the source, the flow of ions 837 is very high, such that they hit the source and heat the fibers/rods 830, causing them to heat and emit, through a thermion emission, a large number of electrons which glut the plasma and enable it to reach high density. The heating of fibers/rods 830 is critical, as well as the collision of the ions with the electron source. This fact also results in the wear of fibers/rods 830 by the effect of vapor and spattering. In order to slow this process it is necessary to thicken fibers/rods 830 as much as possible. The limitation in expanding them is that there is a heat flow to cathode/collector 640. Thus, the optimal solution is to make the fibers/ rods 0.5mm-1 mm in diameter and with a low work function. In this manner it is not necessary to reach high temperatures of 2300 - 2700 C°, but only to 900 - 1300 C°. The materials used are various oxide materials such as tungsten oxide, tantalum oxide, boron oxide, barium oxide, etc. All these examples are in fact ceramics and are not conductors. In order to provide conduction a sintering process is preferably applied, as well as the addition of powdered metals that have both a temperature of fusion and a resistance to spattering that are close to that of the material itself. It is also needed to sharpen the ends 835 to form sharp edges, so that the heat there will result in ignition. Fibers/rods 830 wear due to spattering of the ions and due to the vaporizing process. In order to keep fibers/rods 830 in a cone shape, it is preferable to place materials in their center that can sustain these phenomena, such as tantalum, tungsten, carbon fiber, carbon composite, etc. Ends 835 of fiber/rods 810 are hot, and because of the magnetic field 820, electrons are emitted only from ends 835. The life span of such a source is three orders of magnitude higher than any known in the art, such as filaments, FEC, etc., but requires a substantial amount of ions to ignite it, thus all through the procedure it is necessary to have enough ions and to keep a minimal work temperature.

Fig. 9 is a schematic illustration of a one-stage axial pump having two outlets 900, constructed in accordance with the principles of one preferred embodiment of the present invention. The exemplary inlet 910 is now positioned as shown in Fig. 9. This is more of a symmetrical design, now having electron sources 915 at both ends. Where there was an inlet in Fig. 6, there is now a second symmetrical outlet 920. It's possible to use the system as an ion source at low pressure, such as cleanroom applications. The efficiency is between one and three orders of magnitude improvement over the prior art. At low pressures there is no need for a large pump to bring in the neutral gas of the source, and therefore 70-80% of system costs are saved. This cell can be used as an ion gage to measure the ion gas density in the form of the ion current at the outlet. This cell can also be used to measure pressure because the pressure is linearly proportional to the ion current, which in turn is linearly proportional to the neutral gas molecule density. (The more neutral gas, the more ions.) The gas is typically comprised of 10-micron neutral ion molecules. The sensitivity is more than one order of magnitude better, because efficiency of ionization is this amount. E.g. Bayard-Alpert, the most commonly used ion gage is 0.1 amp-Torr and the Penning Cell achieves 1-10 amp- Torr. By contrast, the present invention has measured 50 to 200 amp-Torr when used as an ion gauge. The ion source can be used on the spattering processes for steel manufacturing. The efficiency is very good. The ion source can be used in implantation processes because of said ion efficiency and better homogeneity of the beam. In manufacturing molecule sized computer chips, the doping process must be very precise. The ions can be used for a mass spectrometer by diverting the beam with a magnetic field or an RF field, wherein either of these fields functions as a mass discriminator. The electrostatic field, however, is not a mass discriminator. The ions can be used for a low energy ion source, i.e. 200 eV or less, for nanotechnology purposes. E.g., the cell can provide an ion source for ion beam epitaxy (IBE), nitrogen beam epitaxy (NBE) or oxygen beam epitaxy (OBE), etc., wherein all these are now popular in all monolayer processes.

Claims

I claim:

1. An open ion source embodied in a vessel having an accelerating voltage applied to at least one outlet, the source comprising: a source of gas molecules, at least one magnet for generating a magnetic field comprising magnetic lines; at least one outlet of the vessel, wherein the opening is sufficiently wide for the ions to exit the vessel; and an electron source at the point of the same at least one outlet, wherein said electrons collide with said gas molecules to produce the ions, and said electrons form a space charge to focus the ions into a beam in order to facilitate their exiting through the at least one outlet, such that said electrons are launched, the ions leave and said magnetic lines begin at the point of the same at least one outlet, and said electrons stay on said magnetic lines from which they are launched.

2. The ion source according to claim 1 , wherein the electron source is a filament.

3. The ion source according to claim 1 , wherein the opening for the at least one outlet is sufficiently narrow to cause the ions to leave with a low probability of returning.

4. The ion source according to claim 1 , further comprising a grid external to the vessel, wherein the grid has a negative voltage to keep the electrons inside the vessel, and to attract the ions out, wherein the grid has openings through which the ions can pass.

5. The ion source according to claim 4, further comprising a secondary outlet beyond said grid, wherein said grid is tilted in order to direct the ions through said secondary outlet.

6. The ion source according to claim 5, wherein the ions are focused before being directed through said secondary outlet.

7. The ion source according to claim 1 , wherein the configuration of the vessel is radial.

8. The ion source according to claim 1 , wherein the configuration of the vessel is axial.

9. The ion source according to claim 1 , wherein the source is used as an ion pump.

10. The ion source according to claim 1 , wherein the source is used as an ion gauge to measure the density of the gases in the vessel.

11. The ion source according to claim 1 , wherein the ions are used for a spattering process.

12. The ion source according to claim 1 , wherein the ions are used for an ion implantation process.

13. The ion source according to claim 1 , wherein the ions are used for a propulsion engine.

14. The ion source according to claim 1 , wherein the source functions at less than 3 Torr.

15. The ion source according to claim 1 , wherein the ions are used for a low energy ion source of less than 200 electron volts.

16. The ion source according to claim 15, wherein the ions are used for nanotechnology purposes.

17. The ion source according to claim 16, wherein the nanotechnology is ion beam epitaxy (IBE).

18. The ion source according to claim 16, wherein the nanotechnology is nitrogen beam epitaxy (NBE).

19. The ion source according to claim 18, wherein the nanotechnology is oxygen beam epitaxy (OBE).

20. A method is for producing ions, wherein the source is embodied in a vessel having an accelerating voltage applied to at least one outlet, the method comprising: providing a supply of gas molecules, providing at least one magnet for generating a magnetic field comprising magnetic lines; providing at least one outlet of the vessel, wherein the opening is sufficiently wide for the ions to exit the vessel; and providing an electron source at the same at least one outlet, wherein said electrons collide with said gas molecules to produce the ions, and the electrons form a space charge to focus the ions into a beam in order to facilitate their exiting through the at least one outlet, such that said electrons are launched, the ions leave and said magnetic lines begin at the point of the same at least one outlet, and said electrons stay on said magnetic lines from which they are launched.