Research Projects

The structures and functions of drugs, proteins, polymers, biosamples, and many others are strongly correlated. Three-dimensional knowledge of proteins at atomic resolution can provide comprehensive information about how they work, react, and bind with each other. X-ray crystallography is already available as the most powerful technique for determining three-dimensional structure, but this technique requires crystalline-ordered structures, which is not possible in proteins, drugs, and biosamples. This is why Nuclear Magnetic Resonance (NMR) spectroscopy is preferred to X-ray crystallography. NMR experiments have an excellent spectral resolution but low sensitivity compared to other spectroscopic approaches. Dynamic nuclear polarization (DNP) has emerged as a prominent technique that can significantly enhance the signal sensitivity 20 – 400 times in NMR spectroscopy. The DNP technique requires a microwave source with good tunable bandwidth. Among all other microwave sources, Gyrotron has emerged as the most promising microwave source for DNP/NMR spectroscopy applications that can produce CW power of a few tens of watts in the millimeter-wave and Sub-THz regimes with significant tunable bandwidth. Therefore, this proposal aims to design and analyze a Sub-THz gyrotron that can produce a few tens of watts of power with significant tunable bandwidth. A time-dependent, nonlinear, self-consistent Multimode code will be made using multimode theories to obtain the output power of the Gyrotron, and it will be validated with the experimental results of the Gyrotron. The RF interaction cavity will be designed in the CST Microwave Studio. Cold analysis of the cavity will be performed using a Time Domain Solver and Eigenmode Solver. Since the operating frequency is very high in the Sub-THz regime, a mesh analysis of the RF interaction cavity will be performed before the particle-in-cell (PIC) simulation. A PIC simulation of the cavity will be performed to obtain the CW output power in the desired operating mode. The results obtained from the simulation will also be compared to the Multimode results. The Ohmic loss will be calculated for the obtained output power. Thermal and structural analysis will be performed using the Fluent Solver and Static Structural Solver of the ANSYS, which will give the temperature and deformation distribution of the RF interaction cavity. The tunable bandwidth will be obtained by using a magnetic tuning scheme and a thermal tuning scheme. Both tuning schemes are different and independent of each other; therefore, tunable bandwidth from both schemes will be combined to obtain higher tunable bandwidth. If the objective of this project is achieved, it will prove to be very useful in developing a Sub-THz Gyrotron in India. It is intended to be useful not only for DNP/NMR spectroscopy applications but also for material processing, cancer therapy, and the detection of radioactive materials.