Microscopy Suite Equipment Fees

Fees/rates for use of equipment in the Microscopy Suite determined through analysis by Government Costing, University of Illinois. In effect starting July 1, 2018; subject to change.

PVT 3D Manual Critical Point Dryer

Critical point drying is commonly used as the final step in the ethanol dehydration of biological samples before they are sputter-coated and imaged using the scanning electron microscope. Critical point drying may also be performed on materials samples, for example those for which air-drying would result in capillary-force-induced collapse of a fragile structure. A sample is brought to the critical point dryer still immersed in 100% ethanol. The chamber is then filled with enough 100% ethanol to completely cover the sample, and the sample is quickly transferred to the chamber. The chamber is then sealed, cooled, and valves are opened to let liquid CO2 in, forcing ethanol out, until liquid CO2 completely replaces the ethanol. At this point the chamber is sealed again and gently heated. Once the chamber pressure exceeds 1072 PSI and the temperature exceeds 31 C, all of the CO2 in the chamber becomes super critical. Above its critical point, the liquid and gas phases of CO2 are in equilibrium, and the CO2 may be slowly drained from the chamber (and the sample) as a gas. Gaseous CO2 leaves the sample without causing the physical destruction one would normally see, for example, when a worm dries out on a sidewalk, as the water in the worm changes phase, from liquid to gas.


  • Advanced auto-pressure and temperature control
  • 1.25" ID chamber and 1.25" height

For additional information about this piece of equipment, see the Calendars, Contacts, and Fees pages.

Primary Contacts
Manufacturer Tousimis
Equipment Model Samdri-PVT-3D
Location B650 R
Phone Numbers (217) 333-5493, (217) 265-5071


* The fee for use is added to our purchase cost for the specific precious metal (gold, gold-palladium, or platinum) expended during coating. Gold and gold-palladium are charged at $0.30/nm, and platinum is charged at $0.45/nm. The added fee is easy to determine for the dual-metal evaporator, for which total thicknesses are reported in nm. For the sputter coaters, at 65 mTorr and 40 mA, gold coats at 3 nm/10 seconds, gold-palladium coats at 1 nm/10 seconds, and platinum coats at 1 nm/10 seconds. So a standard 70-second coat of gold will cost an additional (21 x 0.30) $6.30, a 70-second coat of gold-palladium will cost (7 x 0.30) $2.10, and a 70-second coat of platinum will cost (7 x 0.45) $3.15.

**The Xradia NanoCT system requires staff setup of the sample before X-ray collection.

***The actual hourly cost for this instrument is $91.31. The Beckman Institute subsidizes the TEM at a rate of $41.31 per hour for Internal university users. Enterprise Works users are charged the full $91.31 per hour.