  The BiPo project is dedicated to the measurement of extremely low radioactive
contaminations of SuperNEMO beta-beta source foils (208Tl < 2 microBq/kg and
214Bi < 10 microBq/kg). A modular BiPo1 prototype with its 20 modules and its
shielding test facility is running in the Modane Underground Laboratory since
February, 2008. The goal of this prototype is to study the backgrounds and
particularly the surface contamination of plastic scintillators. After 2
months, a preliminary upper limit on the sensitivity of a 10 m2 BiPo detector
in 208Tl contamination of selenium source foils can be extrapolated to:
A(208Tl) < 7.5 microBq/kg (90 % C.L.).
