A 3D micromechanical compass

ITER has diagnostics with machine protection, basic and advanced control, and physics roles. Several are distributed on the inner and outer periphery of the vacuum vessel. They have reduced maintainability compared to diagnostics in ports. They also endure some of the highest nuclear and EM loads of any diagnostic for the longest time. They include:Inductive sensors for time-integrated and raw inductive measurements; Steady-state magnetic sensors to correct drifts of the inductive sensors;Bolometer cameras to provide electromagnetic radiation tomography; Microfission chambers and neutron activation stations to provide fusion power and fluence; MM-wave reflectometry to measure the plasma density profile and the plasma-wall distance and;Wiring to service magnetics, bolometry, and in-vessel instrumentation. This paper summarises the key technological issues these diagnostics arising from the nuclear environment, recent progress and outstanding R&D for each system.

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“…MEMS investigated for ITER are based on the Lorentz force acting on a current-carrying conductor ( [9] and …”

Section: Outer Vessel Magnetic Sensorsmentioning

confidence: 99%

Nuclear technology aspects of ITER vessel-mounted diagnostics

Vayakis

Bertalot

Encheva

et al. 2011

Journal of Nuclear Materials

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“…In this case, the magnetic sensor is equipped together with three axial accelerometer or stabilization mechanism. The integrated MEMS accelerometers can achieve a tilt accuracy of ±1 • [15]. When a dedicated calibration routine is used [16], the accuracy can be improved to ±0.15 • .…”

Section: Magnetic Sensors For Navigation Purposesmentioning

confidence: 99%

Precise Magnetic Sensors for Navigation and Prospection

Včelák

Ripka

Zikmund

2014

J Supercond Nov Magn

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Navigation, position tracking, search for unexploded ammunition, and geophysical prospection of magnetic or conducting ore are key applications where very small magnetic field signatures and field increments should be detected in the presence of the Earth's magnetic field, typically 50,000 nT. The industry calls for a new generation of portable vectorial magnetic sensors with a precision better than 0.1 nT. This error requirement includes not only sensor noise but also linearity, cross-field error, hysteresis, and perming and also temperature drift of the sensitivity and mainly the offset drift. For application on moving platform, the sensors should also have fast response. We will show that these requirements can be met only by fluxgate sensors. On the other hand, mass market requires cheap, low-power, and small magnetic sensors for portable gadgets; the typical application is compass in mobile phone, with precision of several degrees, corresponding to a 100-nT precision. For these applications, anisotropic magnetoresistance (AMR) sensor is dominant, while integrated fluxgates may penetrate the high-end market.

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“…Since in-plane measurement uses differential sensing capacitors, the in-plane sensitivity is twice the value listed in (5).…”

Section: |mentioning

confidence: 99%

“…The current sensor also shows better linearity and an order of magnitude higher bandwidth than our previous work, making it practical for consumer applications such as navigation and gaming. Moreover since the MEMS structure consists of a single 10 micron thick single-crystal Si layer, the design can be fabricated in a standard MEMS inertial sensor fabrication process, unlike the design presented in [5], which requires three electrically-isolated metal layers on a 1-axis silicon MEMS structure requiring 16× the area of the device presented here.…”

Section: Introductionmentioning

confidence: 99%

Area-efficient three-axis micromechanical magnetic sensor

Rouf

Horsley

2012

2012 IEEE Sensors

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Demonstrated here is a 3-axis Lorentz force magnetic sensor based on a 0.24×0.4 mm 2 MEMS resonator that is the smallest Lorentz force magnetic sensor reported to date. Using a single MEMS structure the sensor can detect magnetic field in two axes. By placing two of these sensors perpendicularly in a single die, three axis field measurement can be performed. The sensor is a MEMS resonator and sensing is performed using excitation current at the device's in-plane and out-of-plane mechanical natural frequencies which are 40.5 kHz and 107.4 kHz respectively. Die-level vacuum packaging results in in-plane and out-of-plane mechanical quality factors of 117 and 220, respectively. With a drive power of 2 mW, the sensor's noise is equivalent to 285 nT/√Hz for z-axis magnetic field inputs and 344 nT/√Hz for x-and y-axis fields, comparable to the performance of 3-axis Hall-effect sensors currently used in smart phones.

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A 3D micromechanical compass

Cited by 88 publications

References 6 publications

Nuclear technology aspects of ITER vessel-mounted diagnostics

Nuclear technology aspects of ITER vessel-mounted diagnostics

Precise Magnetic Sensors for Navigation and Prospection

Area-efficient three-axis micromechanical magnetic sensor

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