A patient interface device that includes a support member sized and configured to span at least a portion of a patient’s face while remaining below the patient’s eyes responsive to the patient interface device being donned by such a patient and a sealing assembly operatively coupled to the support member such that the support member is moveable relative to the support member. The helical light-transmitting fiber is doped with a first wavelength converting material and defines a helical axis. In another embodiment, a well fluid including water, a viscosifying agent, and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is disclosed. A sensitivity correction operating unit is configured to correct a sensitivity of the transition edge sensor based on a relation obtained in advance between an output of the first heater and the peak value measured by the peak analyzing unit.