Spectroscopic Instrumentation using a Variable Focal Length, Scanning Focusing X-ray and Magic Angle Spinning NMR
Instrumentation is the bedrock of spectroscopic investigation regardless of the location on the electromagnetic spectrum being studied. This work develops an improved scanning focusing X-ray source with a variable focal length for high dose enhancement of gold-nanoparticle-containing samples, along with simulations of the resulting beam intensity, shape, and dose profile. It also introduces a 3D printed magic angle spinning (MAS) probe for low-field benchtop NMR, later extended to spin up to 8 samples simultaneously — improving signal for solid KBr and NaBr samples at a cost of a few dollars per unit. (Under embargo until 10/15/2026)
Read on eScholarship →(MAS)n, n ≤ 8
Describes a 3D printed magic angle spinning (MAS) stator capable of stably spinning single powdered solid samples in 4 mm diameter printed rotors up to 7 kHz in a benchtop magnet. Experimental 79Br NMR results for up to n = 3 simultaneously spinning samples are presented, showing that increasing the number of spinning samples increases signal size — demonstrated with powdered KBr and NaBr, including mixed-sample studies in a single probe. A stator design for spinning up to n = 8 samples simultaneously is also shown. The maximum $5 cost of these parts lowers the barrier to entry for solid state MAS NMR.
Arduino NMR
An Arduino-based NMR spectrometer for low-field applications. RF synthesis runs through an SI5351A synthesizer driving a 4-phase switch for homodyne or heterodyne demodulation, with digitally controlled attenuation for RF power output. Received signal is amplified through a dual-stage low-noise amplifier, filtered, and demodulated with a Tayloe detector (SN74LV4052ADR) into in-phase/quadrature components, sampled directly by an Arduino Giga's onboard ADC at up to 12.5 Msps per channel.