ALTEA-Dosi (Anomalous Long Term E ects in Astronauts' - Dosimetry) will utilize the ALTEA hardware: a helmet- shaped device holding 6 silicon particle detectors designed to measure cosmic radiation passing through the detectors. The six identical silicon detector units (SDU) contain three sets of x-y plane silicon strip detectors. Each plane detector is 300 micrometers thick and divided into 64 strips. An event is recorded if at least all 3 x-plane detectors have signals above threshold, and these signals are the sum of the energy deposited in four adjacent strips. The geometry factor of each SDU is 250 cm<sup2< sup="">-sr and is capable of measuring particle trajectory with an angular accuracy of 1.8 degrees and can resolve individual ionizing particles of charge 4 to 28 for energies above 25 MeV/n. In previous research, an electroencephalograph (EEG) measured the brain activity of the crewmember to determine if radiation strikes caused changes in the electrophysiology of the brain in real time. A Visual Stimulator performed tests of the crewmembers' overall visual system.
ALTEA-Dosi will continuously measure the cosmic radiation, without crewmember aid or wearing of the helmet, in the International Space Station (ISS) U.S. Laboratory, Destiny. The ALTEA-Dosi data will also be compared with data collected by Intravehicular Charged Particle Directional Spectrometer (IVCPDS), and Extravhicular Charged Particle Directional Spectrometer (EVCPDS) instruments. The IVCPDS and EVCPDS instruments measure the energy and species of individual ionizing particles of charge 1 to 10, where ALTEA- Dosi measures charge of 4 to 28; therefore, these data sets complement one another allowing for the measurement of the abundances of all ions that contribute signi cantly to crew radiation exposure.