Gyrotron Microwave Source

The gyrotron includes a sealed custom-designed gyrotron tube, superconducting magnet, and control system, all designed to provide high stability, reliability, and ease of operation. Beam propagation to the sample is ensured by high microwave beam quality and corrugated waveguide. The sample is polarized in-situ in a low-temperature NMR MAS probe. 

1H NMR Frequency WB NMR Magnet Gyrotron Frequency Gyrotron Magnet
400 MHz 400/89 Ascend DNP 263 GHz 4.8 T cryogen-free
600 MHz 600/89 Ascend DNP 395 GHz 7.2 T cryogen-free
800 MHz 800/89 USP RS 527 GHz 9.7 T cryogen-free
Technical DNP ENC 2016

263 GHz Klystron Microwave Source

The 263 GHz klystron is a continuous-wave  microwave source designed and manufactured for extended DNP NMR at 400 MHz 1H frequency and 100 K sample temperature.  The klystron provides a DNP option with lower purchase price, operating costs, footprint, and facility requirements compared to the gyrotron product line while retaining high DNP sensitivity and stability.  At 5 W output power, it reaches 90-100% DNP efficiency on biological samples and small molecules in frozen solution while dense material samples perform at > 80% compared to the 263 GHz gyrotron.

The system assembly consists  of: (1) extended interaction klystron oscillator (EIK), (2) a control system with graphical user interface, safety interlocks, power supply and cooling network, and (3) a low-loss microwave transmission line.  It is compatible with a 400 WB Ascend DNP solid-state NMR spectrometer and Bruker low-temperature MAS (LTMAS) probes. 

263 GHz Klystron

LT MAS Probe

  • Low sample temperature (~ 100 K)
  • Cold sample coil and RF circuit
  • 3.2 mm MAS rotor (17 kHz max at 100 K) 
  • WB triple resonance probe (H/C/N)
  • Insert/eject of cold samples
  • Dry low-temperature nitrogen gas supply
  • 3 lines:  bearing, drive and VT
  • Automatic refill of liquid nitrogen supply
  • Waveguide for microwave irradiation
  • Long term operation (days, weeks)

1.9 mm DNP MAS Probe

DNP experiments are performed at low temperature (100 K) for efficient transfer of polarization from electron spins to nuclear spins. Until recently, the spinning frequency at 100 K was limited to 15 kHz with a 3.2 mm rotor. With the introduction of the Bruker 1.9 mm low-temperature MAS (LTMAS) probe, DNP experiments can now be performed at up to 25 kHz MAS frequency for enhanced spectral resolution. The 1.9 mm probe includes pneumatic insert/eject capability at ambient and cold temperature. The ability to change samples while the probe remains cold is critical for optimal use of experiment time. The probe is available with HCN or HX NMR circuits.

Control Systems

  • User Interface
  • Controls and regulation
  • Temps, voltages, water cooling, gyrotron magnet
DNP-NMR Spectrometer