Device for determining a partial pressure of a paramagnetic and/or diamagnetic gas in a gas mixture, comprising: at least two pairs (108, 110, 112, 114, 116) of permanent magnets arranged adjacent to each other for generating a first magnetic field having a first strength and a second magnetic field having a second strength lower than the first strength; at least one first thermal conductivity sensor arranged to be exposed to the first magnetic field and at least one second thermal conductivity sensor arranged to be exposed to the second magnetic field, wherein each of the first and second thermal conductivity sensors (102, 104) comprises: • a membrane for being in thermal contact with the gas mixture, wherein the partial pressure of the gas is associated with a relation between a value of a thermal conduction between the membrane of the first thermal conductivity sensor and the gas mixture and a value of a thermal conduction between the membrane of the second thermal conductivity sensor and the gas mixture; • an electrical heating element (138, 140) for providing a predetermined amount of heat to the membrane; and • means (138, 140) for determining the temperature of the membrane which is associated with the amount of heat provided by the electrical heating element to the membrane and to the thermal conduction between the membrane and the gas; and means for calculating the partial pressure of the paramagnetic and/or diamagnetic gas in response to the temperature of the membrane of the first thermal conductivity sensor and the temperature of the membrane of the second thermal conductivity sensor; wherein the permanent magnets of each pair are respectively arranged above and below a plane containing the membrane; wherein the directions of magnetization of the two permanent magnets of each of the at least two pairs of permanent magnets are opposite to each other; wherein permanent magnets adjacent to each other create magnetic fields having the same direction in the region near the border between them; and wherein the at least one first thermal conductivity sensor is placed in the region of the plane corresponding to borders between adjacent pairs of permanent magnets and the at least one second thermal conductivity sensor is placed in the central part of the space between the permanent magnets of each pair. at least two pairs (108, 110, 112, 114, 116) of permanent magnets arranged adjacent to each other for generating a first magnetic field having a first strength and a second magnetic field having a second strength lower than the first strength; at least one first thermal conductivity sensor arranged to be exposed to the first magnetic field and at least one second thermal conductivity sensor arranged to be exposed to the second magnetic field, wherein each of the first and second thermal conductivity sensors (102, 104) comprises: • a membrane for being in thermal contact with the gas mixture, wherein the partial pressure of the gas is associated with a relation between a value of a thermal conduction between the membrane of the first thermal conductivity sensor and the gas mixture and a value of a thermal conduction between the membrane of the second thermal conductivity sensor and the gas mixture; • an electrical heating element (138, 140) for providing a predetermined amount of heat to the membrane; and • means (138, 140) for determining the temperature of the membrane which is associated with the amount of heat provided by the electrical heating element to the membrane and to the thermal conduction between the membrane and the gas; and • a membrane for being in thermal contact with the gas mixture, wherein the partial pressure of the gas is associated with a relation between a value of a thermal conduction between the membrane of the first thermal conductivity sensor and the gas mixture and a value of a thermal conduction between the membrane of the second thermal conductivity sensor and the gas mixture; • an electrical heating element (138, 140) for providing a predetermined amount of heat to the membrane; and • means (138, 140) for determining the temperature of the membrane which is associated with the amount of heat provided by the electrical heating element to the membrane and to the thermal conduction between the membrane and the gas; and means for calculating the partial pressure of the paramagnetic and/or diamagnetic gas in response to the temperature of the membrane of the first thermal conductivity sensor and the temperature of the membrane of the second thermal conductivity sensor; wherein the permanent magnets of each pair are respectively arranged above and below a plane containing the membrane; wherein the directions of magnetization of the two permanent magnets of each of the at least two pairs of permanent magnets are opposite to each other; wherein permanent magnets adjacent to each other create magnetic fields having the same direction in the region near the border between them; and wherein the at least one first thermal conductivity sensor is placed in the region of the plane corresponding to borders between adjacent pairs of permanent magnets and the at least one second thermal conductivity sensor is placed in the central part of the space between the permanent magnets of each pair.