Radiation protection of aircraft crew: publicly available database of measurements with the silicon spectrometer Liulin on board aircraft

Annual effective doses of aircrew from occupational exposure are typically up to 6 mSv, depending on the number of flight hours, route locations, and solar activity. In many cases, these doses exceed the limit for public exposure to ionizing radiation and thus ICRP recommended their monitoring. Radiation fields at aircraftaltitudes are complex and difficult to measure experimentally. For this reason, the doses are estimated via computer codes that take into account flight parameters like aircraft location and altitude, and solar activity. It is generally accepted, that these calculations should be periodically verified by measurements. Precisemeasurements with tissue equivalent proportional counters are typically short-term only as these detectors are bulky and have only limited battery life. For long-term measurements, which are needed to cover the whole 11-year solar cycle, the silicon spectrometer Liulin is better suited. Liulin is an active dosimeter which records energy deposition events occurring in the semiconductor unit, and – if appropriately calibrated – it estimates neutron and non-neutron component of the ambient dose equivalent. This paper presents a database of long-term measurements performed on board aircraft with the Liulin detector. The measurements started in 2001. For one run, Liulin was placed in the cabin of a Czech Airlines aircraft for approximately 50 days. So far 28 runs were performed, i. e. about 3 500 flights and almost 20 000 flight hours. Flights were flown from Prague to destinations with vertical cut-off rigidities ranging from 1 GV to 17 GV. The most frequent were transatlantic flights from Prague to New York and to Canada. The database comprises more than 105 records where each record contains information on: energy deposition spectra, absorbed dose rates and dose equivalent rates measured with Liulin, date and time, geographic coordinates and altitude. The data are available on the Internet and can be used for instance for verification of computational programs routinely used for estimation of aircrew exposure to cosmic radiation.14th International Congress of Radiation Researc

Publicly available database of measurements with the silicon spectrometer Liulin onboard aircraft

Aircrew members are exposed to ionizing radiation due to their work onboard aircraft. ICRP recommended the monitoring of their effective doses because they regularly exceed the limit of 1 mSv per year for the public exposure. The effective doses are routinely calculated by computer codes that take into account flight parameters like altitude, geographic position, and solar activity. This approach was preferred against personal dosimeters method because the effective dose cannot be evaluated experimentally. However, it is generally accepted, that these calculations should be periodically verified by measurements of H*(10) which is frequently used as a surrogate for effective dose. This report refers about the database (available online http://hroch.ujf.cas.cz/ similar to aircraft/) of long-term measurements with the silicon spectrometer Liulin onboard aircraft. The measurements have been performed since March 2001; so up to date, the database covers a period of 11-years (with a few interruptions) which is usually the duration of the whole solar cycle. The database comprises more than 10(5) individual records of energy deposition spectra, absorbed dose rates, and ambient dose equivalent rates. Each record contains also the information on all flight parameters needed for calculation of dosimetric quantities by the computer codes, and thus the database represent an useful tool for verification of the routine dosimetry of aircraft crews. (C) 2013 Elsevier Ltd. All rights reserved

Instrument intercomparison in the high energy mixed field at the cern-eu reference field (cerf) facility

This paper discusses an intercomparison campaign performed in the mixed radiation field at the CERN-EU (CERF) reference field facility. Various instruments were employed: conventional and extended-range rem counters including a novel instrument called LUPIN, a bubble detector using an active counting system (ABC 1260) and two tissue-equivalent proportional counters (TEPCs). The results show that the extended range instruments agree well within their uncertainties and within 1σ with the H*(10) FLUKA value. The conventional rem counters are in good agreement within their uncertainties and underestimate H*(10) as measured by the extended range instruments and as predicted by FLUKA. The TEPCs slightly overestimate the FLUKA value but they are anyhow consistent with it when taking the comparatively large total uncertainties into account, and indicate that the non-neutron part of the stray field accounts for ∼30 % of the total H*(10)

Radiation Environment at Aviation Altitudes and in Space

On the Earth, protection from cosmic radiation is provided by the magnetosphere and the atmosphere, but the radiation exposure increases with increasing altitude. Aircrew and especially space crew members are therefore exposed to an increased level of ionising radiation. Dosimetry onboard aircraft and spacecraft is however complicated by the presence of neutrons and high linear energy transfer particles. Film and thermoluminescent dosimeters, routinely used for ground-based personnel, do not reliably cover the range of particle types and energies found in cosmic radiation. Further, the radiation field onboard aircraft and spacecraft is not constant; its intensity and composition change mainly with altitude, geomagnetic position and solar activity (marginally also with the aircraft/spacecraft type, number of people aboard, amount of fuel etc.). The European Union Council directive 96/29/Euroatom of 1996 specifies that aircrews that could receive dose of >1 mSv y(-1) must be evaluated. The dose evaluation is routinely performed by computer programs, e.g. CARI-6, EPCARD, SIEVERT, PCAire, JISCARD and AVIDOS. Such calculations should however be carefully verified and validated. Measurements of the radiation field in aircraft are thus of a great importance. A promising option is the long-term deployment of active detectors, e.g. silicon spectrometer Liulin, TEPC Hawk and pixel detector Timepix. Outside the Earth\u27s protective atmosphere and magnetosphere, the environment is much harsher than at aviation altitudes. In addition to the exposure to high energetic ionising cosmic radiation, there are microgravity, lack of atmosphere, psychological and psychosocial components etc. The milieu is therefore very unfriendly for any living organism. In case of solar flares, exposures of spacecraft crews may even be lethal. In this paper, long-term measurements of the radiation environment onboard Czech aircraft performed with the Liulin since 2001, as well as measurements and simulations of dose rates on and outside the International Space Station were presented. The measured and simulated results are discussed in the context of health impact

Dose Distribution Outside the Target Volume for 170-Mev Proton Beam

Dose delivered outside the proton field during radiotherapy can potentially lead to secondary cancer development. Measurements with a 170-MeV proton beam were performed with passive detectors (track etched detectors and thermoluminescence dose-meters) in three different depths along the Bragg curve. The measurement showed an uneven decrease of the dose outside of the beam field with local enhancements. The major contribution to the delivered dose is due to high-energy protons with linear energy transfer (LET) up to 10 keV mu m(-1). However, both measurement and preliminary Monte Carlo calculation also confirmed the presence of particles with higher LET