We target to realise a future satellite mission, LiteBIRD, which will observe full sky at the second Sun-Earth Lagrangian point (L2) and measure the polarisation of the Cosmic Microwave Backgrounds (CMB).
We plan to use Transition Edge Sensor (TES) bolometers to measure the polarisation signal.Measurements of past satellite missions at L2 were disturbed by galactic cosmic rays.Therefore, we need to mitigate the effects from galactic cosmic rays to realise our mission.
Our main concern is the following process:
(1) Cosmic rays deposit energy in silicon substrate where bolometers are.
(2) The energy is propagated by phonons in the silicon substrate.
(3) When some phonons enter a bolometer, the bolometer senses it and spurious signal is created.
In this poster, at first, we show our ideas to mitigate the phonon propagation, as well as the set-up of irradiation test to verify the mitigation ideas.
Next, we show the simulated results of some configurations of parameters using a phonon simulator. Following this, we show the results of irradiation tests,
and compare them to the data from phonon simulations. Finally, we discuss our results and conclude.
|Student (Ph.D., M.Sc. or B.Sc.)||N|
|Less than 5 years of experience since completion of Ph.D||Y|