Area Passive Dosimeter for Life-Science Experiments in Space (Area PADLES) - 12.10.14
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JAXA Area PADLES (Area Passive Dosimeter for Life-Science Experiments in Space) is an investigation that uses area dosimeters to continuously monitor the radiation dose aboard the International Space Station (ISS). Radiation exposure can have significant biological effects on living organisms, and on the biological investigations being done on ISS and on the Japanese Experiment Module Kibo. By installing area dosimeters at 17 fixed locations inside the Kibo Module, continuous area radiation monitoring can be provided throughout the ISS Kibo program.
Science Results for Everyone
Measuring radiation in space is essential to protecting crewmembers, and is also used for developing monitors and shielding for future space vehicles. This investigation used 17 dosimeters placed on the space station to continuously monitor radiation exposure. Data showed that the particle fluxes vary by more than two factors, depending on dosimeter installation orientation. Researchers used the dosimeters to ground-test shielding effect with heavy-ion particles and to monitor area radiation from high energy accelerators. Results will support planning of life sciences experiments on the station and estimation of the shielding effects of various wall thicknesses for future spacecraft.
Japan Aerospace Exploration Agency (JAXA), Tsukuba, , Japan
Sponsoring Space Agency
Japan Aerospace Exploration Agency (JAXA)
ISS Expedition Duration
April 2008 - Ongoing
Previous ISS Missions
From Increment 17, five experiments using the PADLES system started in 2008: area radiation monitoring in Kibo (Area PADLES); dose measurements of biological samples exposed to space radiation (Bio PADLES); personal radiation dosimetry for Asian astronauts (Crew PADLES); various kinds of international cooperative experiments with ISS partners, such as the Matroshka project conducted by the German Aerospace Center in Cologne, and the ALTCRISS project conducted by the National Institute of Nuclear Physics (Dosimetric PADLES); and measurement of the directional dependence of radiation doses inside the Kibo module (Exp PADLES). Past Area PADLES schedule are shown as follows:
Area PADLES #1: Jun 1 2008 to Mar 29 2009 over Increment 17-18,
Area PADLES #2: Mar 16 2008 to Sep 12 2009 over Increment 18-19,
Area PADLES #3: Aug 29 2009 to Apr 18 2010 over Increment 19-22,
Area PADLES #4: Apr 5 2010 Aug 29 2009 to Mar 9 2011 over Increment 23-26,
Area PADLES #5: Apr 5 2011 Aug 29 2009 to May 22 2011 over Increment 26-27,
Area PADLES #6: June to Nobember 2011 over Increment 28-29 (Planed),
Area PADLES #7: December 2011 to May 2012 over Increment 30-31 (Planed),
Area PADLES #8: June to Nobemver 2012 over Increment 32-33 (Planned).
Area PADLES #9: September 2012 to March 2013 over increment 33-34. Area PADLES #10: Mar 2013 to Sep 2013 over Increment 35-36. As part of international cooperative research, Matroshka 2B_Kibo (May 2010 – Mar. 2011,
http://iss.jaxa.jp/en/kiboexp/news/matryoshka20110322.html, ) and Matroshka- R Sperical (May
2012 -, http://iss.jaxa.jp/en/kiboexp/news/120525_padles.html) experiment are conducted
onboard the Kibo. (Rev.E-Inc.43/44)
Crew personal monitoring and area monitoring in the fixed locations must be needed to ISS crews who are equivalent of radiation workers. The knowledge of the continuous radiation environment in ISS is a mandatory step toward a radiation risk assessment, needed for the planning of future manned space missions.
Each space agencys having ISS module are obligated to mesuare and monitor radiation enviroment, on the report of NCRP142's advice. This report is defined Operational Radiation Safety Program for Astronauts in Low-Earth Orbit: A Basic Framework by The National Council on Radiation Protection and Measurements and Medical Operations Requirements Document (MORD) for Space Shuttle, Rev G Section 4.5– Radiation Safety. Also, are obtained data shared for dose management of ISS crew exposure by joint agreement 'The Sharing of Radiation Measurement Data from the Internal Space Station' with SRAG/NASA, IBMP/RSS, JAXA, ESA and CSA on 2005 or international cooperative radiation research activities.
The dosimetric results obtained by area dosimeters are published in JAXA’s PADLES database (http://idb.exst.jaxa.jp/db_data/padles/NI005.html) and are utilized to support the planning of life-science experiments in Kibo and astronauts’ flights, as well as to modify simulation codes of space-radiation models for future manned space activities beyond the earth.
JAXA Area PADLES dosimeter consists of seventeen area dosimeters and the pieces of Velcro, each of which is labeled with the deployment location on the wall inside the JPM and JLP.
They are fixed to Kibo walls with tape and the tether of their casing holder. The Area PADLES holder size is 4.6 cm(w) , 4.6 cm(l) , 9 cm(t) and the weight is 24g. These are assembled and analyzed by the PADLES Group on JAXA TKSC. In the PADLES system, the CR-39 PNTDs measure space-radiation fluence as a function of LET in a LET range above 10keV/um, while the TLDs measure absorbed doses of low LET radiation (less than 10keV/um). These data can be read only after they return to Earth. A series of programs named AUTO PADLES was also developed for the rapid and systematic analysis of the PADLES dosimeters. The package preparation and method for calculating the total absorbed dose, dose equivalent, and mean quality factor over an entire LET range were described in previous papers listed in Section Publications.
Area PADLES provides information about the space radiation environment that ISS operates, and specifically the Kibo module, during the variation of solar activity. Full understanding of space radiation, and the doses surrounding crewmembers, is essential to dose management and space radiation protection.Accumulated data and knowledge are beneficial to design new active and passive types of radiation monitoring and shielding design of spacecraft in the future.
The dosimetry technique is already used for dose management of radiation workers in high energy accelelators. The high-speed microscope scanning image techniques are used in the diagnosis of cancer cells.
Mentioned above article about Unique investigation constraints. Since dosimeters can be analyzed in a terrestrial laboratory (JAXA TKSC), so dosimeters return must be needed. No observation and downlink aren't needed during measurement.
Two task are needed, Area PADLES Installation and Removal.
Tawara H, Masukawa M, Nagamatsu A, Kitajo K, Kumagai H, Yasuda N. Characteristics of Mg2SiO4:Tb (TLD-MSO-S) relevant for space radiation dosimetry. Radiation Measurements. 2011 August; 46(8): 709-716.
Nagamatsu A, Murakami K, Yokota A, Yamazaki J, Yamauchi M, Kitajo K, Kumagai H, Tawara H. Space radiation damage to HDTV camera CCDs onboard the international space station. Radiation Measurements. 2011 February; 46(2): 205-212. DOI: 10.1016/j.radmeas.2010.11.016.
Nagamatsu A, Murakami K, Kitajo K, Shimada K, Kumagai H, Tawara H. Area radiation monitoring on ISS Increments 17 to 22 using PADLES in the Japanese Experiment Module Kibo. Radiation Measurements. 2013 June; epub. DOI: 10.1016/j.radmeas.2013.05.008.
Ground Based Results Publications
Tawara H, Masukawa M, Nagamatsu A, Kitajo K, Kumagai H, Yasuda N. Measurement of a linear energy transfer distribution with antioxidant doped CR-39 correcting for the dip angle dependence of track formation sensitivity. Japanese Journal of Applied Physics. 2008 September 12; 47(9): 7324-7327. DOI: 10.1143/JJAP.47.7324.
NASA Image: ISS028E007155 - Expedition 28 Flight Engineer Satoshi Furukawa posing for a photo with Matroshka-R PADLES (Passive Dosimeter for Lifescience Experiment in Space) Area Dosimeters int the Service Module (SM).
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