Integrated absolute full energy peak efficiency: A measure of photon registration efficiency.

Integrated absolute full energy peak efficiency (IAFEPE) is a measure of photon registration efficiency using the γ-ray spectrometry method. We have derived appropriate formulas and theoretical explanations of IAFEPE for the first time. IAFEPE is a definite integral (Riemann integral) of the photon registration efficiency function within the detection energy range. IAFEPE, along with associated quantities such as mass integrated absolute full energy peak efficiency and surface integrated absolute full energy peak efficiency, allows for the quantitative validation of measurement conditions.

Radon emission fluctuation as a result of biochar application into the soil.

The presented research was focused on the analysis of the impact of biochar application into the soil on the radon exhalation process as a new issue of radiation protection in agriculture. Field measurements of the radon exhalation rate utilizing two methods-active and passive as well as laboratory measurements of the radon emanation coefficient were performed. In laboratory a soil samples with sunflower husk biochar were analysed using the accumulation chamber technique. At the final step the assessment of the effective dose for humans coming from radon exhalation from soil depending on biochar dose applied were evaluated. The doses of biochar applied in the analysed experimental fields were 0, 20, 40, 60, 80, and 100 Mg ha-1. The results show that biochar application into the soil contribute to a decrease in the emanation coefficient from a value around 7% to less than 2% with a simultaneous decrease in the radon exhalation rate from 4.4 to 14.8 mBq m-2 s-1 when the biochar dose increase from 0 to 100 Mg ha-1.

Effect of Fine Size-Fractionated Sunflower Husk Biochar on Water Retention Properties of Arable Sandy Soil.

Biochar application has been reported to improve the physical, chemical, and hydrological properties of soil. However, the information about the size fraction composition of the applied biochar as a factor that may have an impact on the properties of soil-biochar mixtures is often underappreciated. Our research shows how sunflower husk biochar (pyrolyzed at 650 °C) can modify the water retention characteristics of arable sandy soil depending on the biochar dose (up to 9.52 wt.%) and particle size (<50 µm, 50-100 µm, 100-250 µm). For comparison, we used soil samples mixed with biochar passed through 2 mm sieve and an unamended reference. The addition of sieved biochar to the soil caused a 30% increase in the available water content (AWC) in comparing to the soil without biochar. However, the most notable improvement (doubling the reference AWC value from 0.078 m3 m-3 to 0.157 m3 m-3) was observed at the lowest doses of biochar (0.95 and 2.24 wt.%) and for the finest size fractions (below 100 µm). The water retention effects on sandy soil are explained as the interplay between the dose, the size of biochar particles, and the porous properties of biochar fractions.

Impact of soil incorporation of biochar on environmental radioactivity.

Biochar (charcoal made from biomass in the pyrolysis process) has found broad application in agriculture. It helps to improve both the physical and chemical properties of soil through decontamination of heavy metals and pesticides. This work examines the potential for biochar application to improve the radiological condition of soil. We investigated the activity concentration of natural and anthropogenic radionuclides in soil samples collected from fields treated with various doses of biochar (in 1-100 Mg ha-1 ). In addition, we directly measured radon emission rate at the experimental fields. The analyses were performed using gamma spectrometry and an active method for radon emission using an AlphaGUARD instrument equipped with an accumulation box. The results of activity concentration assessments for six radionuclides, five natural and one anthropogenic, show that the only effect of biochar application into the soil is associated with the reduction of soil bulk density by this material. The radon emission rate increased by 6 mBq m-1 s-1 , on average, depending on the biochar dose (from 1 to 100 Mg ha-1 ). Our results demonstrate that application of biochar into soil kept without vegetation had a limited influence on the radioactivity in the environment.

Spatio-Temporal Mapping of L-Band Microwave Emission on a Heterogeneous Area with ELBARA III Passive Radiometer.

Water resources on Earth become one of the main concerns for society. Therefore, remote sensing methods are still under development in order to improve the picture of the global water cycle. In this context, the microwave bands are the most suitable to study land-water resources. The Soil Moisture and Ocean Salinity (SMOS), satellite mission of the European Space Agency (ESA), is dedicated for studies of the water in soil over land and salinity of oceans. The part of calibration/validation activities in order to improve soil moisture retrieval algorithms over land is done with ground-based passive radiometers. The European Space Agency L-band Microwave Radiometer (ELBARA III) located near the Bubnów wetland in Poland is capable of mapping microwave emissivity at the local scale, due to the azimuthal and vertical movement of the horn antenna. In this paper, we present results of the spatio-temporal mapping of the brightness temperatures on the heterogeneous area of the Bubnów test-site consisting of an area with variable organic matter (OM) content and different type of vegetation. The soil moisture (SM) was retrieved with the L-band microwave emission of the biosphere (L-MEB) model with simplified roughness parametrization (SRP) coupling roughness and optical depth parameters. Estimated soil moisture values were compared with in-situ data from the automatic agrometeorological station. The results show that on the areas with a relatively low OM content (4-6%-cultivated field) there was good agreement between measured and estimated SM values. Further increase in OM content, starting from approximately 6% (meadow wetland), caused an increase in bias, root mean square error (RMSE), and unbiased RMSE (ubRMSE) values and a general drop in correlation coefficient (R). Despite a span of obtained R values, we found that time-averaged estimated SM using the L-MEB SRP approach strongly correlated with OM contents.

Calibration factor fluctuation for radiological protection instruments used in Nuclear Medicine Departments - experience from CLOR.

BACKGROUND: The calibration of the dosimetric instruments is a basis of safety of the people working with the ionization radiation. The necessity of calibration is especially important in the institutions where the open radioactive sources are used. The paper presents the abilities of CLOR's radiological protection instruments calibration facility and the important conclusions from calibrations results for group of instruments used in Nuclear Medicine Department in Poland. MATERIALS AND METHODS: The results for five types of instruments dedicated for dose rate as well as for contamination measurements were presented. Analyzes were based on the results presented at calibration certificated of chosen instruments. RESULTS: It has been shown that the calibration factor might fluctuate by 50% in period of one year for particular instrument as well as for more than 100% for two instruments of the same type. CONCLUSIONS: The presented results prove the importance of the calibration process and it is evidence that the calibration process of the radiation protection instruments should be performed periodically for the test of dose rate measurements as well as for contamination measurements abilities.

Radiation hazards in PF-1000 plasma generator fusion research (part 3).

Plasma experiments conducted on the PF-1000 device generate the release of neutrons and ionizing radiation that are the source of immediate exposure to personnel. Neutron activation of materials in the research device and the surroundings is a source of ongoing radiation exposure to the same personnel. Having reported on personnel exposure from ionizing radiation and neutron activation, we now aim to characterize exposure from direct neutron emission generated by the device, and describe the process of ensuring measurement accuracy.

Individual dose monitoring of the nuclear medicine departments staff controlled by Central Laboratory for Radiological Protection.

Presented paper describes the results of the individual doses measurements for ionizing radiation, carried out by the Laboratory of Individual and Environmental Doses Monitoring (PDIS) of the Central Laboratory for Radiological Protection in Warsaw (CLOR) for the medical staff employees in several nuclear medicine (NM) departments across Poland. In total there are48 NM departments in operation in Poland [1] (consultation in Nuclear Atomic Agency). Presented results were collected over the period from January 2011 to December 2011 at eight NM departments located in Krakow, Warszawa (two departments), Rzeszow (two departments), Opole, Przemysl and Gorzow Wielkopolski. For radiation monitoring three kinds of thermo luminescence dosimeters (TLD) were used. The first TLD h collected information about whole body (C) effective dose, the second dosimeter was mounted in the ring (P) meanwhile the third on the wrist (N) of the tested person. Reading of TLDs was performed in quarterly periods. As a good approximation of effective and equivalent dose assessment of operational quantities both the individual dose equivalent Hp(10) and the Hp(0.07) were used. The analysis of the data was performed using two methods The first method was based on quarterly estimations of Hp(10)q and Hp(0.07)q while the second measured cumulative annual doses Hp(10)a and Hp(0.07)a. The highest recorded value of the radiation dose for quarterly assessments reached 24.4 mSv and was recorded by the wrist type dosimeter worn by a worker involved in source preparation procedure. The mean values of Hp(10)q(C type dosimeter) and Hp(0.07)q (P and N type dosimeter) for all monitored departments were respectively 0.46 mSv and 3.29 mSv. There was a strong correlation between the performed job and the value of the received dose. The highest doses always were absorbed by those staff members who were involved in sources preparation. The highest annual cumulative dose for a particular worker in the considered time period was 4.22 mSv for Hp(10)a and 67.7 mSv for Hp(0.07)a. In 2011 no case of exceeding the allowed dose limits was noted.

Exposure to ionizing radiation of workers in Poland.

Results of individual monitoring of occupied workers based on the doses estimations carried out by Central Laboratory for Radiological Protection (CLOR) in Warsaw has been presented. In 2011, about 5000 persons from 330 institutions were monitored. Monitoring service in CLOR is based on two doses assessment methods, Kodak films and MCP-N thermo luminescent detectors. Presented results show that 97% of registered doses were less than 1 mSv and only about 0.1% of assigned doses were higher than 20 mSv. The monitored workers were divided in four groups: medical, scientific, industrial and others. Six cases of excess of the 20 mSv annual dose limit were registered in medical, three in scientific and three in industrial group. The average annual dose in each particular group was calculated: 0.51 mSv in medical, 0.62 mSv in scientific, 0.48 mSv in industrial and 0.44 mSv in others.