A Planar CMOS Field-Emission Vacuum Magnetic Sensor
We have fabricated a CMOS vacuum magnetic sensor that exploits the deflection of an electron beam produced by field emission by a perpendicular magnetic field. The device is planar and fabricated by conventional lithography and etching processes. An extremely high magnetic field sensitivity of 4times103%/T is reported.
CMOS magnetic sensors with integrated ferromagnetic parts
The paper deals with Hall and flux-gate magnetic field sensors consisting of integrated combination of CMOS ASICs and planar ferromagnetic components. Ferromagnetic parts are made of a soft amorphous alloy, integrated at the CMOS wafer in a post-processing production phase. When the sensors are exposed to an in-plane magnetic field, under the peripheries of ferromagnetic parts appears a strong magnetic induction perpendicular to the wafer surface. This perpendicular field is sensed either by Hall plates or planar coils. In the case of Hall magnetic sensors, such ferromagnetic parts give a magnetic gain of 2–10. Compared to conventional integrated Hall magnetic sensors, the new sensors have up to 10 times higher magnetic resolution and they respond to a magnetic field parallel with the surface of the chip. They are used as current sensors or angular position sensors. In the case of flux-gate sensors, both the saturation-forcing coil and the pick-up coils are realized as planar coils, using metallization layers that exist in the CMOS process. The integrated flux-gate technology is illustrated by a low-power two-axis magnetic field sensor suitable for a portable electronic compass.
Magnetic plasma confinement for laser ion source.
A laser ion source (LIS) can easily provide a high current beam. However, it has been difficult to obtain a longer beam pulse while keeping a high current. On occasion, longer beam pulses are required by certain applications. For example, more than 10 micros of beam pulse is required for injecting highly charged beams to a large sized synchrotron. To extend beam pulse width, a solenoid field was applied at the drift space of the LIS at Brookhaven National Laboratory. The solenoid field suppressed the diverging angle of the expanding plasma and the beam pulse was widened. Also, it was observed that the plasma state was conserved after passing through a few hundred gauss of the 480 mm length solenoid field.