LiteBIRD is a proposed JAXA satellite mission to measure the CMB B-mode polarization with unprecedented sensitivity ( \sigma _ { r } \sim 0.001 ) . To achieve this goal , 4676 state-of-the-art TES bolometers will observe the whole sky for 3 years from L2 . These detectors , as well as the SQUID readout , are extremely susceptible to EMI and other instrumental disturbances e.g . static magnetic field and vibration . As a result , careful analysis of the interference between the detector system and the rest of the telescope instruments is essential . This study is particularly important during the early phase of the project , in order to address potential problems before the final assembly of the whole instrument . We report our plan for the preparation of a cryogenic testbed to study the interaction between the detectors and other subsystems , especially a polarization modulator unit consisting of a magnetically-rotating half wave plate . We also present the requirements , current status and preliminary results .