Abstract: A closed cycle cryocooler is thermally connected to an elongated, cup-shaped sample well and cools down the sample well. Gaseous helium at a relatively low pressure is introduced into the sample well so that, as the sample well is cooled by the cryocooler, the gas in the sample well is also cooled. A sample is attached to a sample stick assembly which is then lowered into the sample well where the sample is cooled by the cooled gas to carryout experiments at low temperature. The sample stick assembly is mechanically attached to the spectrometer magnets and a flexible rubber bellows connects the sample stick assembly to the sample well so that vibration generated by the cryocooler is not transferred to the sample.

Abstract: A closed cycle cryocooler system for cooling a sample includes a cryocooler that receives helium gas and provides a cooled helium gas, a flexible interface that receives the cooled helium gas and provides the cooled helium gas to a rigid stinger assembly configured and arranged to provide the cooled helium gas to a cryostat. The flexible interface may include a first gas flow path that routes gas to the rigid stinger assembly, and a second gas flow path receives return gas from the rigid stinger.

Abstract: In an electron paramagnetic resonance spectrometer, a closed cycle cryocooler is used to cool gaseous helium, which is then circulated around a sample to cool the sample by direct convection. Since the sample is not mechanically connected to the refrigerator, no vibrations are transmitted from the refrigerator to the sample and the sample can be quickly removed and replaced. The cooled helium can be passed through a Joule-Thomson expansion device before circulating the cooled helium around the sample to further cool the helium. In addition, a vacuum pump can be connected to the helium outlet after circulating the cooled helium around the sample to increase the pressure differential across the Joule-Thomson expansion device and further cool the helium. In order to raise the temperature of the cooled helium, a heater can be placed about the cooled helium line upstream from the sample.

Abstract: In an electron paramagnetic resonance spectrometer, a closed cycle cryocooler is used to cool gaseous helium, which is then circulated around a sample to cool the sample by direct convection. Since the sample is not mechanically connected to the refrigerator, no vibrations are transmitted from the refrigerator to the sample and the sample can be quickly removed and replaced. The cooled helium can be passed through a Joule-Thomson expansion device before circulating the cooled helium around the sample to further cool the helium. In addition, a vacuum pump can be connected to the helium outlet after circulating the cooled helium around the sample to increase the pressure differential across the Joule-Thomson expansion device and further cool the helium. In order to raise the temperature of the cooled helium, a heater can be placed about the cooled helium line upstream from the sample.

Abstract: A closed cycle cryocooler is thermally connected to an elongated, cup-shaped sample well and cools down the sample well. Gaseous helium at a relatively low pressure is introduced into the sample well so that, as the sample well is cooled by the cryocooler, the gas in the sample well is also cooled. A sample is attached to a sample stick assembly which is then lowered into the sample well where the sample is cooled by the cooled gas to carryout experiments at low temperature. The sample stick assembly is mechanically attached to the spectrometer magnets and a flexible rubber bellows connects the sample stick assembly to the sample well so that vibration generated by the cryocooler is not transferred to the sample.

Abstract: In an electron paramagnetic resonance spectrometer, a closed cycle cryocooler is used to cool gaseous helium, which is then circulated around a sample to cool the sample by direct convection. Since the sample is not mechanically connected to the refrigerator, no vibrations are transmitted from the refrigerator to the sample and the sample can be quickly removed and replaced. The cooled helium can be passed through a Joule-Thomson expansion device before circulating the cooled helium around the sample to further cool the helium. In addition, a vacuum pump can be connected to the helium outlet after circulating the cooled helium around the sample to increase the pressure differential across the Joule-Thomson expansion device and further cool the helium. In order to raise the temperature of the cooled helium, a heater can be placed about the cooled helium line upstream from the sample.

Abstract: A method and an apparatus for investigating the imperishability of n liquid foodstuffs using electron spin resonance (ESR) exposes samples of the foodstuffs to an elevated temperature for an extended time-period. At predetermined intervals during the period, the intensity of an ESR signal of each sample is measured and plotted vs. time in a diagram for that sample. The time of a superproportional increase in intensity is detected for each foodstuff. The number n of different foodstuffs is determined by dividing the predetermined interval by the measurement time. The n samples are investigated simultaneously by sequentially cycling the n samples through a common sample vessel. Each time, the intensity of the ESR signal of the sample is measured and then plotted in a diagram unique to that foodstuff. The sequence of foodstuffs are cycled through the sample vessel until a predetermined number m of measuring points per foodstuff has been attained.