Gamma background and neutron flux measurements at Basic Ecological   Observatory Moussala
  The Basic Ecological Observatory (BEO) Moussala is located at 2925m above sea level and one of the main activities is connected with gamma background and neutron dose rate monitoring. The neutron and gamma measurements are carried out with help of site radiation monitor Harwell Type 3208-1. The dose rate of ambient gamma background is measured with SBN-90, improved with the embedded microprocessor system using automatic PC based system. A cross check and inter calibration with existing TLD (thermo luminescent dosimeters) at BEO Moussala which is a part of the monitoring network of INRNE is presented. A polyethylene sphere with a layer of lead serving as a neutron breeder, extending the energy range from about 40 MeV to several hundred MeV is presented as a project in development. Another project in development is the construction of active detector based on SNM-15 detectors for a dose rate measurement of cosmic neutrons is described. Preliminary study of the performances of the detectors are carried out. A further project for muonic telescope similar to the yet developed is discussed. 
Y. Dimov, M. Guelev, L. Hristov, P.Ivanov, A. Mishev, A. Nishev, J.   Stamenov and B. Vachev