# Innovative Instrumentation for High Magnetic Field DNP NMR

> **NIH NIH R01** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2024 · $518,992

## Abstract

The proposed research is focused on innovative instrumentation that will enable fundamental advances in the
field of Dynamic Nuclear Polarization (DNP) NMR at high magnetic fields, making this powerful technique far
more readily available and useful to the national and international biomedical research communities. In DNP
NMR, a high frequency microwave source is used to irradiate electron - nuclear transitions, thereby transferring
the high spin polarization in the electron spin reservoir to the nuclear spin system through hyperfine and dipolar
interactions. The resulting enhancements in NMR signals dramatically reduce data acquisition times, and thus
DNP NMR is now considered a major advance in NMR spectroscopy. Recently, new biological insights were
obtained using DNP on highly complex systems like HIV-1 capsid proteins, needle-like structures from bacterial
secretion systems or in-cell proteins. In DNP experiments at the high magnetic fields where contemporary NMR
research is conducted, the required microwave frequency is in the terahertz (THz) regime: 460 GHz, 527 GHz
and 593 GHz for g=2 electrons at 700 MHz, 800 MHz and 900 MHz 1H NMR frequencies respectively. However,
the enhancement in the DNP NMR signal falls off rapidly with increasing magnetic field and correspondingly
increasing microwave frequency. Time domain DNP techniques such as Nuclear Orientation via Electron Spin
Locking (NOVEL), Time Optimized (TOP) DNP and the Integrated Solid Effect (ISE) do not fall off with increasing
magnetic field and are thus very attractive at high magnetic fields. However, these techniques are currently
limited to low magnetic field NMR spectrometers due to the lack of the high power, pulsed THz sources and
instrumentation required to perform pulsed DNP experiments at high magnetic field. NOVEL requires large Rabi
frequencies (>10 MHz) in pulses of a few nanoseconds. The required power levels are in the kilowatt range and
are further exacerbated by the poor electromagnetic field coupling into the sample in the present-day magic
angle spinning (MAS) sample holders. Our pioneering research will provide the instrumentation needed for high
magnetic field DNP NMR by developing pulsed gyrotron oscillators capable of generating > 5 kW output power
at 460 GHz and higher. We will also develop a laser driven semiconductor switch that will be used to form the
nanosecond scale pulses needed for NOVEL experiments. For TOP DNP, we will use reflection of the gyrotron
output to produce the required train of nanosecond scale pulses. We will demonstrate a frequency swept gyrotron
source by using fast voltage control of the gyrotron’s electron gun to meet the requirements of ISE experiments.
The proposed research will use available gyrotron magnets, power supplies and a 460 GHz DNP NMR
spectrometer to speed up the research and reduce costs. The efficacy of these techniques will be demonstrated
in DNP NMR experiments at 460 GHz using an available spectrometer. Collectiv...

## Key facts

- **NIH application ID:** 10749028
- **Project number:** 5R01EB004866-16
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** RICHARD J TEMKIN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $518,992
- **Award type:** 5
- **Project period:** 2006-02-07 → 2025-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10749028

## Citation

> US National Institutes of Health, RePORTER application 10749028, Innovative Instrumentation for High Magnetic Field DNP NMR (5R01EB004866-16). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10749028. Licensed CC0.

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