Progress of shielding effect characteristics with water-filled tools for space radiation in 2010-2016

The shielding effect with water-filled tools, called “Protective curtain”, for space radiation was experimentally verified in the Russian Segment of International Space Station (ISS). The Protective curtain consists of a stack board made of the hygienic wipes and towels for ISS crews. The passive dosimeters consisted of a combination of luminescence detectors (TLDs: LiF:Mg,Ti, CaSO4:Dy and Al2O3:C and OSLDs: Al2O3:C) and plastic nuclear track detectors (PNTDs: CR-39 HARZLAS/TD-1). Totally 12 passive dosimeter packages were installed in front of/behind the Protective Curtain with 6.3 g/cm2 in mass thickness for measuring the dose reduction rate. The experiment was launched in June 2010 and has been continued by March 2016 through 6 sessions. The dose reduction rate which is the dose ratio with/without Protective Curtain varies from 53 to 93 % in absorbed doses and from 52 to 97 % in equivalent dose, respectively. The observed dose includes secondary radiations such as neutrons and target fragments as we can see in LET spectra. In this presentation, we will show the recent progress of shielding effect characteristics of Protective Curtain and long term dose variations related to the ISS orbital parameters and solar activity.42nd COSPAR Scientific Assembl