  The piece of NESTOR vacuum chamber with the ceramic insertion for DC-monitor
and RF-shields was simulated by using both transient and wake field solvers of
CST Studio Suite. For a 6 mm gap between two RF-shields the contributions of
the assembly considered to the longitudinal broadband (BB) impedance Z/n and
the loss factor kloss are 0.71 Ohm and 0.21 V/pC, correspondingly. These
estimates are the second largest after those of the RF-cavity that were
obtained till now for the NESTOR ring components.
  Contributions from a beam position monitor (BPM) are also obtained by
simulation and compared with analytical estimates obtained earlier.
  We also present in the paper the frequency content of longitudinal impedance
in the frequency range from 0 to 16 GHz for all ring components considered.
