Short‐term variation of cosmic radiation measured by aircraft under constant flight conditions

Abstract

The temporal variations in cosmic radiation on aircraft under constant flight conditions were measured by a Liulin detector. Rather than a commercial long-distance aircraft, we used a military reconnaissance aircraft performing a circular flight at a constant altitude over the Korean Peninsula. At 9144 m (30,000 ft), the mean and standard deviation of the radiation dose rate (among 35 measurements) was 2.3 and 0.17 μSv/h, respectively. The experiment yielded two observational results. First, the dose rate changed over a flight time of 5-7 h; second, no strong correlation was revealed between the cosmic rays observed from the ground-based neutron monitor and the radiation doses at aircraft altitude. These observations can provide insight into the short-term variation of cosmic radiation at aviation altitudes. When discarding various negligible factors, it is postulated that the changes in the geomagnetic field and the air density still could affect the variation of cosmic radiation at aircraft altitude. However, various factors are less known about the dependence on the cosmic radiation. Therefore, investigations of possible factors are also warranted at the monitoring points of space weather.

Global real-time dose measurements using the Automated Radiation Measurements for Aerospace Safety (ARMAS) system

“…A large number of measurements used for postflight analysis have been made using Tissue Equivalent Proportional Counters (TEPCs) under GCR background conditions and not during major space weather SEP events [ Dyer et al ., ; Beck et al ., ; Kyllönen et al ., ; European Commission Radiation Protection 140 , ; Getley et al ., ; Beck et al ., ; Latocha et al ., ; Meier et al ., ; Beck et al ., ; Dyer et al ., ; Hands and Dyer , ; Getley et al ., ; Gersey et al ., ; Tobiska et al ., , , ]. Some of the measurements have included neutron flux and dose equivalent measurements with solid‐state detectors [ Dyer et al ., ; Hands and Dyer , ; Ploc et al ., ; Lee et al ., ].…”

Assessment of spectral and angular characteristics of sub-GLE events using the global neutron monitor network

“…However, recent measurements discuss the possible contribution of radiation belt particles as well as changes in the geomagnetic field and air density to variable radiation environment in the vicinity of Earth and within the Earth's atmosphere (e.g. Lee et al, 2015;Atwell et al, 2017). In addition, some natural radio-nuclides from the Earth's crust also contribute to the atmospheric radiation, particularly in near surface region of the atmosphere (e.g.…”

Analytical Representations for Characterizing the Global Aviation Radiation Environment Based on Model and Measurement Databases

“…There have been a number of campaign and flight databases created over the past few decades that capture a wide range of dosimetric measurements. Aircraft (Dyer et al, 2009, , , ; Federico et al, ; Getley et al, ; Iles et al, ; Lee et al, ; Meier et al, ; Meier, Matthiä, et al, ; Meier, Trompier, et al, ; Ploc et al, ), balloon (Mertens, ; Mertens et al, ), and ISS (Dachev, ; Dachev et al, , ) measurements have provided valuable information.…”

“…These high northern and southern latitudes as well as cross‐equatorial flights demonstrated that spectrometers can provide reliable dose assessments for real‐time, in‐flight aircrew monitoring and provide timely alerts for solar particle events. Lee et al () also used the Liulin detector to measure the dose rate environment over the Korean peninsula on military aircraft at a constant altitude of 9 km during geomagnetically quiet to slightly disturbed conditions (0 ≤ Kp ≤ 4) during the decline of solar cycle 24. Both the Liulin and Rayhound detectors compared favorably with the TEPC and were within the generally accepted tolerance of 20% (Dyer et al, ).…”