Patent ID: 7106061

Claim:
A probe head for nuclear magnetic resonance measurements in which at least a first kind of nuclei with a first, higher resonance frequency and a second kind of nuclei with a second, lower resonance frequency are excited within a magnetic field, said probe head comprising: a) a first input/output terminal for feeding a signal of said first, higher resonance frequency for exciting said first kind of nuclei and for receiving, resp., a resonance signal emitted by said first kind of nuclei; b) a second input/output terminal for feeding a signal of said second, lower resonance frequency for exciting nuclei of said second kind of nuclei and for receiving, resp., a resonance signal emitted by said second kind of nuclei; c) a measuring coil cooperating with a sample, said measuring coil having a first terminal end and a second terminal end, said first terminal end being coupled to said first input/output terminal and said second terminal end being coupled to said second input/output terminal; d) a first stop circuit tuned to signals of said higher resonance frequency of said first kind of nuclei, said first stop circuit being arranged between said second terminal end and said second input/output terminal, said first stop circuit, further, comprising a first line having a length equalling a quarter wave length of said higher resonance frequency of said first kind of nuclei, said first line being arranged in series with said measuring coil.