Project Info

Electronics Control and Readout for Quantum Hall Sensor

Wouter Van De Pontseele
wouter.vandepontseele@mines.edu

Project Goals and Description:

This project will purchase a Paragraf graphene Hall probe for cryogenic (mK) low-field measurements and develop a single-channel, low-cost readout so students can do high-sensitivity field measurements without buying a full commercial unit. The work is interesting because it blends cryogenic instrumentation needs with practical low-noise electronics design and calibration.

This project aims to deploy a Paragraf Cryogenic mK Low Magnetic Field Graphene Hall probe (EGHKX03P03, S‑PCB only, “Engineering Proof”) and build a university-budget readout chain that can resolve small magnetic fields in cryogenic experiments while maintaining good linearity and low drift. The sensor family is designed for cryogenic operation (down to mK) and has a 4-terminal symmetric Hall element that supports “spinning current” style measurement, which is widely used to suppress offset and reduce low-frequency (1/f) noise in Hall readout systems.​​

Key goals and why they matter:

  • Create a single-channel readout that uses a constant-current bias (preferred over constant-voltage bias to avoid nonlinearity from field-dependent resistance).​

  • Implement phase-swapped/spinning-current measurements (rotate bias and sense connections using analog switching) and compute a differenced output (e.g., phase subtraction/averaging) to cancel offset and slow drift.​​

  • Benchmark performance (noise floor, resolution, linearity) versus vendor specifications such as sensitivity (up to ~1700 V/A/T at 300 K for the X03) and stated linearity bounds.​

  • Produce a documented, reusable “open” readout recipe (schematic + firmware/software + test procedure) appropriate for a cryostat environment (long cables, thermal EMFs, pickup).​

  • Deliverables: working readout prototype, calibration procedure, and a short internal technical note enabling future students to reproduce measurements quickly and reliably.

More Information:

Grand Challenge: Engineer the tools of scientific discovery.

  • Paragraf “GHS Basic Readout” technical note (biasing, constant-current recommendation, interpreting Hall output).​

  • Paragraf EGHSX03Q02 and EGHKX03P05 datasheets (performance metrics, pin pairing symmetry, cryogenic operating range).​

  • Paragraf MiST reference manual sections describing SCMT/spinning-current suppression concepts and system-level error sources (useful as a conceptual reference even if MiST isn’t purchased).​

  • Background on spinning-current offset/1/f-noise suppression in Hall systems (e.g., literature on four-phase spinning schemes).​

  • Optional component starting points: ADG5434 quad SPDT switch product information; AD8429 low-noise instrumentation amplifier product information.​

Primary Contacts:

Wouter Van De Pontseele, (email wouter.vandepontseele@mines.edu) | Jake Croft, (email TBD) | Joseph Templet | Rosie Warburton, (email TBD)

Student Preparation

Qualifications

  • Basic analog electronics (op-amps/instrumentation amps, noise, grounding, filtering)

  • Comfort with lab instruments (AWG, low-noise DC supply/current source, DMM/nanovoltmeter or DAQ)

  • Ability to solder/assemble small electronics and follow ESD-safe handling practices (strongly preferred for sensor work).

TIME COMMITMENT (HRS/WK)

5

SKILLS/TECHNIQUES GAINED

  • Low-noise measurement design: bias-current cleanliness, offset/drift mechanisms, cabling/pickup mitigation.​

  • Spinning-current style modulation/demodulation and quantitative noise analysis (time-series logging, spectra, Allan deviation if appropriate).​

  • Practical calibration workflow across temperature/field conditions and validation against vendor spec metrics (sensitivity/linearity).​

MENTORING PLAN

  • Bi-Weekly 30–45 min technical check-ins plus one longer design review at each milestone (requirements → prototype → cryo test → calibration writeup)

  • Pair the student with a “first build” bench test plan (room-temp characterization) before any cryostat deployment, then iterate based on measured noise/offset behavior

  • Maintain shared documentation (schematics, test logs, and a short operating procedure) and require brief written updates to build good engineering habits

Preferred Student Status

Junior
Senior
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