Nmr spectrometer with refrigerator cooling

Abstract

An NMR spectrometer comprising an NMR magnet system () disposed in a helium tank of a cryostat and an NMR probe head () disposed in a room temperature bore of the cryostat, which contains a cooled RF resonator () for receiving NMR signals from a sample to be investigated, and a cooled pre-amplifier (), wherein the NMR probe head () is cooled by a common multi-stage compressor-operated refrigerator (), wherein the refrigerator () comprises a cold head and several heat exchangers () at different temperature levels, wherein the refrigerator () is disposed at a spatial separation from the cryostat in a separate, evacuated and thermally insulated housing () and wherein at least one cooling circuit with cooling lines, which are thermally insulated by a transfer line () is disposed between the housing () containing the heat exchangers () and the NMR probe head (), is characterized in that additional cooling lines to an LNtank () or radiation shield () disposed in the cryostat and surrounding the helium tank are provided, and the refrigerator () also cools the LNtank () or the radiation shield (). The inventive NMR spectrometer comprises a simple and inexpensive device for matching the holding time of LNto that of LHe through cooling the LNtank using the refrigerator provided for cooling the NMR probe head and without great expense.