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

Uncertainties in linear energy transfer spectra measured with track-etched detectors in space

Polyallyldiglycol carbonate-based track-etched detectors can measure linear energy transfer (LET) spectra of charged particles. Accuracy of the spectra is affected by many factors whose effects are difficult to quantify. Typically, only uncertainty arising from the randomness of particle detection is reported in scientific literature. The aim of this paper is to classify the sources of uncertainties of an LET spectrum measurement and provide a simple model for the calculation of the combined uncertainty. The model was used for a spectrum measured with the track-etched detector (Harzlas TD-1) on board of the International Space Station from May-October 2009. For some spectrum bins the largest contribution to the combined uncertainty came from the uncertainty arising from the randomness of particle detection. For other bins it came from the uncertainty of the calibration curve. Contribution from the cross talk between bins was small for most of the bins as the width of the bins was relatively large compared to the intrinsic resolution of the track-etched detector. The analysis showed that sources of uncertainties other than the randomness of particle detection should not, in general, be neglected

N.B.: When citing this work, cite the original article. Original Publication:

The potential of dual-energy computed tomography for quantitative decomposition of soft tissues to water, protein and lipid in brachytherap

Liulin silicon semiconductor spectrometers as cosmic ray monitors at the high mountain observatories Jungfraujoch and Lomnický stit

Currently, most cosmic ray data are obtained by detectors on satellites, aircraft, high-altitude balloons and ground (neutron monitors). In our work, we examined whether Liulin semiconductor spectrometers (simple silicon planar diode detectors with spectrometric properties) located at high mountain observatories could contribute new information to the monitoring of cosmic rays by analyzing data from selected solar events between 2005 and 2013. The decision thresholds and detection limits of these detectors placed at Jungfraujoch (Switzerland; 3475 m a.s.l.; vertical cut-off rigidity 4.5 GV) and Lomnicky stıt (Slovakia; 2633 m a.s.l.; vertical cut-off rigidity 3.84 GV) highmountain observatories were determined. The data showed that only the strongest variations of the cosmic ray flux in this period were detectable. The main limitation in the performance of these detectors is their small sensitive volume and low sensitivity of the PIN photodiode to neutrons