Introduction

By means of a unique modular magnetic configuration, the Hanks HM² e-Gun offers a more efficient electron beam heated source. It is 2/3 the size of traditional evaporation sources, yet provides the same crucible volume, evaporation rate, and power capability of physically larger guns.

The Hanks HM² e-Gun is approximately 350% more efficient magnetically, which is reflected in its reduced physical size. It is also markedly different from other e-Guns because of the unique method used to generate the magnetic field. Other manufacturers that use a transverse field for beam focusing place the permanent magnet horizontally at the rear of the source and conduct the magnetic field lines through steel pole pieces. The use of this system results in an inherently high magnetic leakage flux and thus, larger magnets must be used.

In the Hanks HM² e-Gun, the magnetic field generator is rotated 90° from a horizontal to a vertical position. It is made of two sets of a number of small individual magnets arranged vertically along the two sides of the crucible and the beam path. This allows placement of the top ends of the magnets at a position slightly above the crucible top, which is the optimum position from which to deliver the flux to the desired magnetic field area. This very short length path reduces leakage flux. Leakage flux is further reduced by the use of a steel plate which connects the bottom end of the magnets to form a unitized magnetic structure. The desired changes and shaping of the magnetic gradient along the beam path are accomplished by shaping and positioning the individual magnets along the two sides of the beam path. The magnets can be either permanent magnets, electromagnets, or both, depending upon the application.

Features and Benefits

• Elimination of beam curl—Electrons impact the melt at a 90° angle providing maximum energy transfer with a minimum of energy-wasting secondary electrons. This is the result of a carefully graduated magnetic field which is stronger at the top of the crucible than at the bottom
• Elimination of pole pieces—Vertically mounted magnets result in less magnetic flux leakage. This improves electron capture, and it improves efficiency. Thus, the more compact a magnetic circuit is, the smaller its source footprint.
• Easy filament alignment—Filaments are quickly, easily, and very accurately aligned by simply removing the emitter assembly from the vacuum system. An alignment tool is included with each gun.
• More efficient electron collimation—Our new design produces a better collimated beam with fewer stray electrons.
• Minimal filament distortion—By clamping the filament adjacent to the spiral, filament movement is held to a minimum.
• Electron tails—Special filament shielding prevents low energy electrons from leaving the filament environment, eliminating electron tails.
• Larger crucible size—40 cc crucible volume in a footprint 2/3 the size of traditional evaporation sources.

200 Hz Sweep Controller

The Hyper-Unimelt high frequency sweep system virtually eliminates tunneling and source material eruptions. Operating from 0-200 Hz, it is over twice as fast as any other beam sweep system.

The high Hz sweep capability facilitates uniform heating of dielectric and sublimating materials. Without it, tunnels will develop, producing high evaporation rates, but with restricted distribution. Uniform heating is essential for maintaining a uniform flat evaporant surface. Maintaining the uniformity of the surface of the material being evaporated produces superior results.

When used with the PSC-600 programmable sweep controller, an unlimited number of sweep pattern geometries are possible.

Hanks HM² e-Guns are manufactured and protected under one or more of the following patents:

Patent No. 4,835,789
Patent No. 4,891,821
Patent No. 4,947,404