Session PL. There are 14 abstracts in this session.

Session: Instrumentation, poster number: 328
A multi-channel magnetic field sensor boosts sensitivity in nuclear magnetic resonance
Román Picazo
Helmholtz-Institut Mainz, Mainz, Germany
The development of powerful sensors of weak magnetic fields is crucial for spectroscopic applications, in particular for nuclear magnetic resonance (NMR). The NMR signal due to only thermal equilibrium is too weak and separating it from background noise is a challenge. Here, we present measurements of NMR magnetization gradient instead of magnetization by using a multi-channel magnetic field sensor, which is sensitive to magnetic field gradient but insensitive to common-mode magnetic field noise.

As a first application, we measure liquid-state molecules ensembles obtaining enhancement of magnetic field measurement sensitivity. We show an increase of the sensitivity of the signal while reducing the susceptibility to noise. Our technique opens a door for fundamental physics, exotic spin-dependent interactions and axion dark matter.

Session: Instrumentation, poster number: 329
An Ultra-low Cost Software-Defined Radio-based NMR spectrometer
Carl A. Michal
University of British Columbia, Vancouver, Canada
The development of an ultra-low-cost software-defined radio (SDR)-based NMR spectrometer is described. The spectrometer uses a recently released open-hardware SDR system that incorporates a complete high-performance transmitter and receiver that are connected to a host computer over USB3. Multiple boards can be used for a multi-channel (multi-transmit and multi-receive) system. The spectrometer control software provides a friendly graphical user interface for operation and data processing along with a simple but powerful (C-language based) pulse programming interface. The high-level of integration of the SDR board means a complete NMR transmit/receive channel can be assembled without soldering, for US$300 per rf channel, requiring only external power amplifiers and pre-amplifiers. The complete hardware and software system will be described

Session: Instrumentation, poster number: 330
A Large Segmented Double-Tuned Quadrature High-field MR Coil With Exceptional Tuning Stability
F. David Doty1; Glenn Doty1; Scott Deese1; JB Spitzmesser1; Daniel Arcos1; Dave McCree1; Laura Holte1; Paul Ellis1; Sylvie Clerjon2; Jean-Marie Bonny2
1Doty Scientific, Inc., Columbia, SC; 2INRA, QuaPA, AgroResonance, Saint-Genes-Champanelle, France
There is urgent need for a more satisfactory high-field whole-body double-tuned (DT) rf coil to better support the use of local coils in applications of hyperpolarized 13C methods in MRI. We present a novel HF-segmented DT coil design showing an unprecedented degree of minimization of E fields, even with long samples, with little compromise in B1 efficiency at either frequency and with greater potential for scalability to whole-body DT T/R CP coils at high fields. The design was optimized using a combination of time-domain CST simulations and frequency-domain COMSOL-RF simulations, and experimentally validated in a 200MHz/53MHz coil of 25 cm OD and 20 cm ID, fully loaded with samples from 0 to 350 mM salinity (as in salt-cured foods).

Session: Instrumentation, poster number: 331
Frequency Agile Gyrotrons for Electron Decoupling Dynamic Nuclear Polarization
Faith Scott1; Edward Saliba1; Chukun Gao1; Natalie Golota1; Brice Albert1; Nicholas Alaniva1; Erika Sesti1; Eric Choi1; Anil Jagtap2; Johannes Wittmann3; Michael Eckardt4, 5; Wolfgang Harneit5; Björn Corzilius3; Snorri Sigurdsson2; Alexander Barnes1
1Washington University in St. Louis, St. Louis, MO; 2University of Iceland, Reykjavik, Iceland; 3Goethe University Frankfurt, Frankfurt am Main, Germany; 4Johannes Gutenburg-Universität Mainz, Mainz, Germany; 5Universität Osnabrück, Osnabrück, Germany
Dynamic Nuclear Polarization (DNP) increases NMR signal intensity but is often accompanied by decreased resolution due to hyperfine line broadening. Frequency swept EPR control allows for electron decoupling which attenuates hyperfine broadening effects. We have designed and built several frequency agile gyrotrons as microwave sources for pulsed DNP and demonstrate them here with frequency swept DNP experiments. An arbitrary waveform generator changes the voltage at the anode, which changes the microwave frequency at a rate of up to 20 MHz/μs. We also present a new gyrotron designed to emit up to 300 W microwave power. Increased microwave power will increase the electron Rabi frequency at the NMR sample for more efficient DNP transfers and higher enhancement values.

Session: Instrumentation, poster number: 332
Superconducting 32 T magnet milestone reached on the path towards 30+ T HTS NMR
Hubertus W. Weijers; Arneil P. Reyes; Sanath K. Ramakrishna; Mark D. Bird
NHMFL / FSU, Tallahassee, FL
Breakthrough: The first superconducting user magnet to go well beyond the 1 GHz 1H NMR 23.5 T barrier of Nb-based Low Temperature Superconductor (LTS) magnets, was operated at 32.1 T as confirmed using 63Cu-NMR. This driven Condensed Matter Physics magnet demonstrated initial homogeneity and drift characteristics far better than expected, without shims or stabilizing technologies. With additional Bi-2212 and Bi-2223 HTS NMR magnet technology development activities, the commissioning of this 32 T magnet, expertise in shimming and stabilization, the MagLab arguably has the technology base needed to bring to far better uniformity > 30 tesla, driven superconducting NMR magnets, suitable for high resolution NMR.

Session: Instrumentation, poster number: 333
An Automated Setup for Polarization-Enhanced Broadband Nuclear Quadrupole Resonance (NQR) Spectroscopy
Jarred Glickstein; Soumyajit Mandal
Case Western Reserve, Cleveland, OH
NQR spectroscopy of 14N is emerging as a promising technique for quantitative analysis and authentication of pharmaceuticals and dietary supplements. However, the intrinsically low signal-to-noise ratio (SNR) of 14N NQR limits the accuracy of the measurement. Polarization enhancement is a useful method for significantly increasing the SNR of NQR spectra. In this work a magnet with a strong, uniform field (∼0.65T) was constructed and placed adjacent to the NQR probe. The sample was moved between the permanent magnet and probe using a sample tube which is mechanically driven by a rack and pinion. The latter allows the sample to be held at any arbitrary fixed point as needed and enables the speed of the sample’s motion to be accurately controlled.

Session: Instrumentation, poster number: 334
O-ring free, tunable pressure and temperature MAS NMR rotor capability
Flaviu Turcu1; Aurel Jurjiu1, 2; Ionut Cardan1; Vasile Muresan1; Ioan Burda1; Simion Simon1, 2
1"Babes-Bolyai" University, Physics Department, Cluj-Napoca, Romania; 2Interdisciplinary Research Institute on BioNanoSci, Cluj-Napoca, Romania
High resolution magic angle spinning (MAS) nuclear magnetic resonance (NMR) is one of the most powerful techniques for studying molecular structure and dynamics, regardless of the system phases.
In situ measurements on a system under tunable pressure and temperature is a current topic of intensive research given its prospective widespread application across fields such as biophysics/protein science materials, catalysis, geochemistry, food preservation and processing and medicine.
Because of major technical challenges intrinsic to development of sealable MAS rotor, leakage free constructions have never been achieved. Here we report the O-ring free design for tunable pressure and temperature (TPT) MAS rotor capable of leakage free and compatible with microwaves or optical irradiation.

Session: Instrumentation, poster number: 335
Cryogen Free Superconducting Magnets for Solid State NMR and DNP Applications
Eugeny Kryukov1; Jeremy Good1; Paul Jonsen2
1Cryogenic Ltd, London, United Kingdom; 2Talavera Science,, Harrogate, UK
We present 9.4 T and 12.1 T superconducting magnet systems for low temperature solid state NMR and DNP applications. The systems are equipped with integrated variable temperature inserts cooled by a single GM or PT type cryocooler to both magnet and VTI, allowing sample temperatures down to 1.3 K. We achieve magnetic field homogeneities of 2 ppm and 0.5 ppm within a 10 mm diameter sphere volume using 4 and 8 coil sets of superconducting shims respectively. Persistent mode field degradation is less than 0.1 ppm/hour, achieved via superconducting joints between coil sections.

Session: Instrumentation, poster number: 336
Experimental Benefits of Cryogen Free Technologies in Magnetic Resonance
Jeremy Good1; Eugeny Kryukov2; Paul Jonsen3
1Cryogenic Ltd, London, United Kingdom; 2Cryogenic Ltd, London, UK, London, United Kingdom; 3TalaveraScience, Harrogate, N/A
The two main uses of liquid helium in magnetic resonance is to cool superconducting magnets and for performing experiments at very low temperatures. Having become reliant on liquid helium, these experiments are disrupted when there are delivery problems with this cryogen. However, there is an alternative way forward using cold heads and these are being developed to offer more credible alternatives to liquid cryogen technologies. The use of cryogen free technology has provided unique advantages compared to their ‘wet’ versions including more experimental versatility and productivity improvements as the examples in protein EPR and quadrupolar solid state NMR demonstrate.

Session: Instrumentation, poster number: 337
Nuclear Spin Optical Rotation Detection with Low Field NMR Instrument  
Yue Zhu
Texas A&M University, College Station, Texas
The Nuclear Spin Optical Rotation (NSOR) effect describes the rotation of linearly polarized light interacting with the nuclear magnetic moment. This effect is related with the strength of the hyperfine interactions. Therefore, both information from nucleus and electron could be obtained at the same time if used with a Nuclear Magnetic Resonance (NMR) spectrometer. In this project, a low field NMR spectrometer is customized to demonstrate the ability of detecting hetero-nuclear NMR and NSOR signal simultaneously with recirculation method for the first time. In addition, the multiplet structure due to the J-coupling between different nuclei is observed at the same time. Multiple nuclei NSOR measurement enabled the determination of properties of electronic states at multiple sites in the molecule.

Session: Instrumentation, poster number: 338
A Broadband, Ultra Low-Loss Duplexer for High Field EPR Spectroscopy
Jeson Chen
Bridge12 Technology, Inc, Framingham, MA
We present the design and analysis of an ultra low-loss, broadband, quasi-optical device, for changing the polarization state of microwave radiation that employs a wire grid polarizer and a flat mirror. By changing the separation distance between the mirror and the grid polarizer of the Polarization Transforming Reflector (PTR), it is possible to change the polarization state of a linearly polarized Gaussian incident beam to clockwise and counter-clockwise polarization. This polarization-changing behavior can be attained in a quasi-optical circulator (duplexer) for high-field EPR spectroscopy to separate the incident microwave beam from the reflected beam. In this contribution we will review the PTR’s performance and discuss its relevance to HF EPR spectroscopy.

Session: Instrumentation, poster number: 339
NMR RF Switching Circuit


Joseph Asta
Merck & Co., Inc., Kenilworth, NJ
An RF switching circuit has been developed that allows a user to switch the RF transmitter path of an NMR Spectrometer using a software controlled virtual button. The switching circuit reduces the need for manual re-cabling. It is primarily applicable to NMR spectrometers with two transmitter channels connected to a probe having three channels.
The software is Java based, platform independent (Windows, Linux, MacOS, Solaris), and will function on both Agilent/Varian and Bruker spectrometers.
The RF switching circuit adds the capability at a greatly reduced cost compared to adding a third channel to an NMR Spectrometer.

Session: Instrumentation, poster number: 340
Focused Microwave Intensity for Pulsed Dynamic Nuclear Polarization in Rotating Solids
Pinhui Chen; Faith Scott; Chukun Gao; Edward Saliba; Erika Sesti; Nicholas Alaniva; Brice Albert; Natalie Golota
Washington U in St Louis, St. Louis, MO
In order to perform pulsed Dynamic Nuclear Polarization (DNP) with electron decoupling in NMR, inducing a higher electron Rabi frequency, or γB1, is essential. Our current simulated maximum γB1 is 0.70 MHz with an incident microwave output power of 5 W. Based on a high-frequency structural simulator (HFSS), the maximum γB1 implementing a Teflon lens is 3.4 MHz for our 3.2 mm rotor. However, physical restraints inside the NMR stator result in sub-optimal focus of the microwave intensity. A larger 9.5 mm rotor can accept the insertion of a lens within the rotor to focus the microwave intensity. Based on HFSS, the maximum γB1 frequency with a Teflon lens is 5.8 MHz.

Session: Instrumentation, poster number: 341
Nano-Sensors for Magnetic Resonance
Raiker Witter1, 2; Torsten Scherer2
1Tallinn University of Technology, Tallinn, Estonia; 2Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
Development of nano-spectroscopic devices provides the opportunity for investigation of micro- and nano-sized samples and for pushing the limit of detection (LOD).
For inductive detection, miniaturized coil-like structures are of relevance where the measured samples are located in the centre. The relative signal-to-noise ratio for magnetic resonance experiments significantly improves for small coil diameter.
We test the limits of manufacturing coil structures with magnetic susceptibility correction situated on substrates with low electrical losses. Dimensions below 1.0 µm are obtained.