A method for analyzing an ozone concentration comprising the steps of: providing at least one catalytic chamber having an ozone decomposition path between an inlet portion and an outlet portion thereof; receiving a sample flow of gas containing ozone by the inlet portion of the at least one catalytic chamber and along the ozone decomposition path ; decomposing a totality of the ozone of the sample flow of gas into oxygen in an exothermic reaction along the ozone decomposition path of the at least one catalytic chamber ; measuring a first temperature value at a first position and measuring a second temperature value at a second position, the first and second positions being associated with the inlet and outlet portions ; providing the oxygen exiting the outlet portion of the at least one catalytic chamber into an external thermally conducting conduit ; cooling the oxygen flowing in the external thermally conducting conduit ; providing the cooled oxygen back in the at least one catalytic chamber using an internal thermally conducting conduit provided across the at least one catalytic chamber from a first arbitrary portion to a second arbitrary portion ; measuring a third temperature value at the first arbitrary portion and measuring a fourth temperature value at the second arbitrary portion ; evaluating the ozone concentration of the sample flow of gas based on the temperature difference between the second temperature value and the first temperature value and calibration data, said evaluating the ozone concentration of the sample flow of gas being further based on the temperature difference between the fourth temperature value and the third temperature value; and generating a signal indicating the ozone concentration. providing at least one catalytic chamber having an ozone decomposition path between an inlet portion and an outlet portion thereof; receiving a sample flow of gas containing ozone by the inlet portion of the at least one catalytic chamber and along the ozone decomposition path ; decomposing a totality of the ozone of the sample flow of gas into oxygen in an exothermic reaction along the ozone decomposition path of the at least one catalytic chamber ; measuring a first temperature value at a first position and measuring a second temperature value at a second position, the first and second positions being associated with the inlet and outlet portions ; providing the oxygen exiting the outlet portion of the at least one catalytic chamber into an external thermally conducting conduit ; cooling the oxygen flowing in the external thermally conducting conduit ; providing the cooled oxygen back in the at least one catalytic chamber using an internal thermally conducting conduit provided across the at least one catalytic chamber from a first arbitrary portion to a second arbitrary portion ; measuring a third temperature value at the first arbitrary portion and measuring a fourth temperature value at the second arbitrary portion ; evaluating the ozone concentration of the sample flow of gas based on the temperature difference between the second temperature value and the first temperature value and calibration data, said evaluating the ozone concentration of the sample flow of gas being further based on the temperature difference between the fourth temperature value and the third temperature value; and generating a signal indicating the ozone concentration. <EOS>