JAXA's PADLES dosimeters have been utilized in many international collaborative projects.

Dosimetric PADLES is "international collaborative experiments in the field of space radiation measurement" using the PADLES radiation dose measurement system.

At the ICCHIBAN project, Intercomparison of the Response of Space Radiation Dosimeters and Spectrometers to Heavy Ion Beams at the Accelerator Facilities, high measurement accuracy of the PADLES dosimeter was evaluated.

JAXA also has many experiment experiences with the radiation dose measurements onboard the ISS. JAXA has been participating in the MATROSHKA project, series of experiment that installed the Phantoms*1 on the outside and inside of the ISS to evaluate the radiation dose on Extravehicular Activity (EVA), and the ALTCRISS project, the experiment that uses tissue equivalent materials*2 to evaluate radiation influence that depends on shielding material.

*1 Phantom
This is a human mannequin without limb that simulates a human body. It is composed of materials equivalent to human tissue with respect to radiation dose. It simulates the reactions that occur in the internal environment of a human body when exposed to space radiation.
*2 Tissue equivalent material
This is materials equivalent to human tissues in each body structures and organs with respect to radiation dose.

1. MATROSHKA project

MATROSHKA patch logo

This is an international multi-user experiment led by the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt : DLR). For measuring the radiation doses of astronauts during inside and outside activities on the ISS, the MATROSHKA Phantom that human mannequins composed of human bones and simulated organs was installed on the outside and inside of the ISS. The experiment began on February 2004.


JAXA°«s PADLES dosimeter was set up to head of the MATROSHKA Phantom.

The MATROSHKA Phantom which put in the radiation detector of each country was wore a poncho (left), put in a shield container (center), then covered outer of multilayer thermal insulation (right).

The MATROSHKA Phantom measured the space radiation dose for about one year after installed outside wall of the Zvezda Service Module of the ISS (below).

MATROSHKA Phantom installed on Russian service module(SM), Zvezda
The MATROSHKA Phantom on the Zvezda Service Module of the ISS

Three organizations of JAXA/ESA/ROSCOSMOS conducted the MATROSHKA2 experiment together in the Japanese Experiment Module, Kibo from 2010.

The PADLES dosimeter was launched on the Progress M-05M (37P) on April 29, 2010. And then a Cosmonaut installed 25 dosimeters in the MATROSHKA Phantom body. The Phantom was installed in Kibo by JAXA astronaut Noguchi. After carrying out measurement for about 11 months, the dosimeter was returned on the Soyuz TMA-M (24S) on March 16, 2011.

JAXA astronaut Noguchi (right) with the Phantom which put in the dosimeter on May 2010 (Credit: NASA)

On May 2010, the situation of the Phantom which put in the dosimeter and JAXA astronaut Noguchi°«s work, image from Kibo onboard camera (Credit: NASA)
On March 10, 2011, the Phantom was uninstalled and moved from Kibo to the russian module by ESA astronaut Paolo Nespoli. (Credit: NASA)
On March 10, 2011, the Phantom was uninstalled and moved from Kibo to the russian module by ESA astronaut Paolo Nespoli, image from Kibo onboard camera (Credit: NASA)

2. ALTCRISS project

ALTCRISS (Alteino Long Term Monitoring of Cosmic Rays on the International Space Station) is an international collaborative experiment led by the National Institute of Nuclear Physics (Istituto Nazionale di Fisica Nucleare : INFN). This experiment investigated effectiveness of the shielding materials and thickness of the ISS crew cabins by installing dosimeters to the shielding block inside the Zvezda Service Module of the ISS.

The experiment began on October 2005, and four measurement runs have been completed so far. The measured data are now being processed at each participating organizations.

Dosimeters installed on the shielding block inside the Russian service module, Zvezda
Installed dosimeters (indicate by allows) on the shielding block inside the Zvezda Service Module of the ISS

3. BRADOS / Space-ICCHIBAN project

BRADOS (Theme name : Acquisition of Data About the Radiological, Electromagnetic and Different Physical Environments on Board ISS, and Their Effects on the Safety of the Crew, Space Equipment and Materials) is an international collaborative experiment led by IMBP and NIRS and in which ISS partners participates. This is the intercomparison experiments of the performance using the different passive radiation dosimeters and deep dose impact experiments in the same time and a same location.

The experiment began on May 2007, and three measurement runs have been completed so far. The measured data are now being processed at each participating organizations.

The constitution of the JAXA dosimeter which it carried by SI- phase2 experiment. A polycarbonate case is distributed so that each country has same condition.The dosimeter of each country is put in an aluminum container case to keep the same condition, and it is installed in Russia service module.
(left) The constitution of the JAXA dosimeter for the SI- phase2 experiment. A polycarbonate case is distributed so that each country has same condition.
(right) The dosimeter of each country is put in an aluminum container case to keep the same condition, and it is installed in the Zvezda Service Module of the ISS.