# A Compact, 395 GHz Traveling Wave Tube (TWT) Amplifier for DNP-NMR and EPR Spectroscopy

> **NIH NIH R43** · BRIDGE 12 TECHNOLOGIES, INC. · 2021 · $350,000

## Abstract

Project Summary / Abstract
We propose to develop a compact, cost-effective Traveling Wave Tube (TWT) amplifier at 395 GHz with 1.5 W
continuous wave power and 20 GHz instantaneous bandwidth for application in Dynamic Nuclear Polarization
(DNP) enhanced solid-state and solution-state NMR and Electron Paramagnetic Resonance (EPR)
spectroscopy. With DNP, the inherently small signal intensities in a NMR experiment can be enhanced by up to
two orders of magnitude. This significantly increased overall sensitivity will be highly beneficial for analytical
applications of NMR spectroscopy as well as in the structure determination of bio-macromolecules using NMR
methods.
Currently, DNP is performed with either low power solid-state sources (whose output power is limited to a few
mW at frequencies > 300 GHz) and at low temperatures in the range of 20-30 K (to compensate for low
microwave power) or with large, gyrotron systems which can generate 50 W of power. Gyrotrons are
expensive and do not possess sufficient tuning bandwidth (<0.1%) necessary for investigating a wide range of
DNP experiments and thus require expensive sweep coils in the NMR magnets. The proposed TWT will
address all the above concerns. The TWT is expected to cost less than one-fourth of the cost of a gyrotron
system, provide 20 GHz of instantaneous bandwidth and will be a compact table-top system. These
advantages will allow a larger number of researchers to take advantage of the sensitivity boost offered by DNP
in NMR experiments.
In Phase I, we will design, build and test a prototype system. The successful demonstration of such a system
in Phase I will enable us to develop a commercial product in Phase II with superior performance. The
technology is scalable and can be used at frequencies as high as 527 GHz (800 MHz NMR). A higher peak
power version of the device will advance the state-of-the-art in high field EPR spectroscopy. As an ultimate
result of this project, we expect Bridge12 to offer a commercial TWT at 395 GHz (600 MHz NMR) for DNP-
NMR and EPR spectroscopy. This will greatly accelerate structure determination of bio-macromolecules of
relevance to human disease research funded by NIH.

## Key facts

- **NIH application ID:** 10259439
- **Project number:** 1R43GM142412-01
- **Recipient organization:** BRIDGE 12 TECHNOLOGIES, INC.
- **Principal Investigator:** Jagadishwar Rao Sirigiri
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $350,000
- **Award type:** 1
- **Project period:** 2021-09-03 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10259439

## Citation

> US National Institutes of Health, RePORTER application 10259439, A Compact, 395 GHz Traveling Wave Tube (TWT) Amplifier for DNP-NMR and EPR Spectroscopy (1R43GM142412-01). Retrieved via AI Analytics 2026-09-03 from https://api.ai-analytics.org/grant/nih/10259439. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*