Basic considerations about experimental approaches to the B-mode of the   CMB Polarization
  The B-mode detection of Cosmic Microwave Background polarization will require new technological developments, able to get sensitivities at least 2 orders of magnitude better than for the E-mode. This really ambitious goal cannot be reached simply by either improving the present technology or by adding more detectors to current design, at least in the frame of having a new space mission operating within a decade. Thus, the scientific community have to take important decisions about the most suitable technologies on which converge the needed effort. Basically, at present two receiver families do exist: bolometric and radiometric. Both of them are continuoulsly improving their basic performances, but the optimal approach to B-modes may require some decisions have to be taken in short time scale. In any case, radiometric and bolometric receivers have to deal with some common sources of systematics as well as they both require some cryogenics. Thus, we should expect that systematics and cryogenics may play as watershed line in designing future experiments aimed at measuring the B-mode of Cosmic Microwave Background. 
S. Cortiglioni (INAF-IASF Bologna), E. Carretti (INAF-IRA)