Tag Archives: Dewar Flasks

EPR電子順磁共振儀耗材 Dewar Flasks (Cold-Finger Dewars)

Impurity Analyses – Clear Fused Quartz (CFQ) vs. Suprasil (Synthetic Quartz)
EPR Sample Tubes and Accessories
EPR Cells
Dewar Inserts
‧ Dewar Flasks (Cold-Finger Dewars)
Variable Temperature Accessories
Electrolytic Cells for EPR
Miscellaneous EPR Supplies

Dewar Flasks (Cold-Finger Dewars)
•Large Nitrogen Dewar Flasks
•Liquid Nitrogen Dewar Flask

Large Nitrogen Dewar Flasks

Want the easiest way to take your samples to liquid nitrogen temperatures?
Dewar Flasks provide you with a convenient alternative to VT systems for studies at -195°C. Wilmad makes flasks for almost all common cavity resonators including those requiring reservoirs “off-set” from the center axis. Use these for cavities with iris controls near the Dewar Flask reservoir. Select either Clear Fused Quartz (CFQ) or Suprasil “cold-fingers.” All Dewar Flasks are silvered about the reservoir. Each Dewar Flask is shipped with protective nylon meshing.

Large 150mL Dewar Flasks
For longer experiments (25-45 minute sample immersion), part number WG-853 series are for resonators requiring reservoirs ‘off-set’ from the center axis.
***Special Note: Not recommended for contemporary EPR.

Small 50mL Dewar Flasks
When you have plenty of sample signal and experiments take only 15-25 minutes, these small Dewar Flasks are ideal. They can handle up to 4mm OD sample tubes or solid samples mounted onto the end of 4mm OD quartz rods. WG-819s are for resonators requiring reservoirs ‘off-set’ from the center axis.

Technical Tip:
Keeping Dewar Flask reservoirs and “cold-fingers” clean will extend the hold time by reducing the rate of nitrogen boil.

Wilmad uses “-Q” to designate versions using Suprasil in the critical portions of the cell. All other cells are prepared from Clear Fused Quartz (CFQ).

Liquid Nitrogen Dewar Flask

Liquid nitrogen is an easily transported and economic source of coolant, whose boiling point is far below the freezing point of water without pressurization. This unique feature makes it useful for a wide range of applications in basic science research such as cell cryopreservation, sample degasification by freeze-pump-thaw cycle and cold trap for experiments involving vacuum lines.

Continuing our goal to remain the world’s leading provider of NMR and EPR consumables and accessories we’ve added a high quality Liquid Nitrogen Dewar Flask for these applications.


~30% cheaper but with equal or better quality than major manufacturers’ corresponding products

~Highly vacuumed (<10-6 torr) and fully silvered cylindrical Dewar minimizes liquid nitrogen loss during storage
~Unique 3 inch aluminum base increases stability
~Better protection for the vacuum hose
~Supplied with Black Ethafoam Stopper