Delayed fluorescence resulting from triplet–triplet annihilation in crystalline 9,10-diphenylanthracene was observed by means of steady-state fluorescence measurements under magnetic fields of ≤10 T. At five specific magnetic fields, four peaks and one dip in the magnetic field dependence of fluorescence intensity were observed, proving that exchange-coupled triplet pairs were generated in the course of triplet–triplet annihilation. The dip was in the opposite direction predicted for singlet channel triplet–triplet annihilation. Further analysis using the stochastic Liouville equation confirmed that the closest exchange-coupled triplet pair in crystalline 9,10-diphenylanthracene is quenched via both triplet channel and singlet channel triplet–triplet annihilation.

We measured the vibration of a prototype superconducting magnetic bearing (SMB) operating at liquid nitrogen temperature. This prototype system was designed as a breadboard model for LiteBIRD low-frequency telescope (LFT) polarization modulator unit. We set an upper limit of the vibration amplitude at 36 µm at the rotational synchronous frequency. During the rotation, the amplitude of the magnetic field produced varies. From this setup, we compute the static and AC amplitude of the magnetic fields produced by the SMB magnet at the location of the LFT focal plane as 0.24 G and 3 × 10 −5 G, respectively. From the AC amplitude, we compute TES critical temperature variation of 7 × 10 −8 K and fractional change of the SQUID flux is δ Φ/Φ 0 | ac = 3.1 × 10 −5 . The mechanical vibration can be also estimated to be 3.6 × 10 −2 N at the rotation mechanism location.