Research Collaborate Lab Bench


The equipment and resources available at the National Biomedical EPR Center are detailed below.

EPR Spectrometers

Bruker ELEXSYS EPR Spectrometer Systems (2)
Special Features
Super X bridge, high dynamic range (90 dB), X-band, 10-inch magnet, Super Hi-Q resonator, ER 4103TM cylindrical resonator, ER 4116DM dual-mode TE102/TE012 resonator ER 4117D-R dielectric resonator, ER 4117D-M dielectric mixing resonator, ER 4119HS-WI high-sensitivity optical resonator, and liquid nitrogen cryostat. One of the ELEXSYS spectrometers is equipped with field frequency lock, helium cryostat, Bruker DICE ENDOR with ENH01252 cavity, A300 RF power amplifier (0.3–35 MHz), and 3100L RF power amplifier (250 kHz–105 MHz). Bruker E-600 series W-band CW-EPR (including W-band cylindrical resonator, W-band bridge, superconducting magnet, room temperature sweep coils, and cryostat).
Bruker ELEXSYS 580 Pulsed Spectrometer
Special Features
Pulse X-band spectrometer and Q-band with DEER, DQC, and ENDOR capabilities at cryogenic temperatures.

To measure long-range distances between paramagnetic probes and/or coupled nuclei within biomedically relevant proteins and peptides.
Bruker EMX Spectrometer
Special Features
Standard high-quality X-band research instrument.

Photoexcited paramagnetic states; spin-label studies; spin-label studies of cellular membrane fluidity and oxygen uptake.
Time-Domain ESR Spectrometer at 9 GHz with 9-inch Magnet
Special Features
Saturation recovery capability to 0.1 µs; very high speed data acquisition system.

Measurement of T1 of spin labels; measurement of transient response of spin systems to various excitations.
Low-Frequency EPR Spectrometer Station
Special Features
CW and NARS spectroscopy at 0.5–1 GHz, 1–2 GHz, 2–4 GHz, and 4–8 GHz at temperatures down to 15–20 K.

Transition metal EPR studies, protein distance measurements.
Varian E-9 EPR Multifrequency Spectrometer
Special Features
0.5–1 GHz bridge; L-band 1-2 GHz bridge; S-band 2–4 GHz bridge; C-band 4–8 GHz bridge; K-band 18 GHz bridge; Q-band 35 GHz bridge; various loop-gap resonators; liquid helium cooling at all of the above frequencies (down to 15–20 K).

Transition metal EPR; forbidden transitions; in vivo studies on mice; study of very small samples at 35 GHz.
Varian E-109 Century Series EPR Spectrometers
Special Features
Field-frequency locks; photomodulation from dc to 5 kHz; saturation transfer spectroscopy; excellent sensitivity; loop-gap resonators.

EPR of free radicals in solution; EPR of metal complexes in frozen solution; photoexcited paramagnetic states; spin-label studies; spin-label studies of cellular membrane fluidity and oxygen uptake.
Modified Varian E-110 Q-Band (35 GHz) Spectrometer Station
Special Features
High sensitivity, low phase noise Q-band microwave bridge on a varian-based console and magnet system.
Multiquantum Q-Band Spectrometer with 10-inch Bruker Magnet
Special Features
Multiquantum and saturation recovery spectroscopy at 35 GHz.

Resolution of multiple spectral components that arise from conformational equilibria.
W-Band Spectrometer
Special Features
92.5–95.5 GHz CW and saturation recovery spectrometer. Can measure T1s to 200 nS.

Specialized for use with room-temperature liquid-phase aqueous samples.


Electronic Equipment
  • Agilent E5505A Phase Noise Measurement System
  • Agilent N5242A PNA-X Network Analyzer (heads to 240 GHz)
  • Agilent E8363C PNA Network Analyzer (50 MHZ to 40 GHz)
  • Agilent N9030A PXA Signal Analyzer (3 Hz–44 GHz)
  • Agilent Spectrum Analyzers to 100 GHz
  • Agilent Microwave Power Meters to 100 GHz
  • Frequency Counters to 40 GHz
  • Agilent DSO9404 Digitizing Oscilloscope to 40 GSPS
  • Analog oscilloscopes to 400 MHz
  • Pulse, delay, and signal generators

Software resources include the following:

  • Agilent Advance Design System is a PC-based microwave circuit design, simulation, and layout system
  • Ansys High-Frequency Structure Simulator (HFSS) running on a Dell computer with dual 12-core 2.3 GHz Xeon processors with 512 GB of memory and nVidia CUDA enabled graphics processors, permitting objective (rather than intuitive) design of loop-gap resonator coils and cavities, and is useful for modeling RF field distributions
  • Ansys Maxwell 3D, a field simulator that uses finite-element analysis to solve electromagnetic problems; it is run on the same computer as Ansoft HFSS