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DO-RA Innovative Technology for Space Radiation Monitoring Onboard Civilian Aircrafts

V. Elin¹, O. Sharts ², A. Kairis ³, M. Merkin ⁴

Introduction

Currently, the interaction with Internet of Things online (IoT and IIoT) became much easier and accessible after creating various ecosystems which are taking into account the individual demands for modern innovative technologies from consumers.

This type of ecosystem may be attributed to newly created “Aviation system for monitoring of cosmic ionizing radiation exposure to flight crew and passengers” with the use of modern innovative DO-RA technologies http://intersofteurasia.ru/o-radiaczii/620.html.

It is well known that during the air flights which billions of people use annually, we make our travel at the altitudes of 10-12 km above the ground. During these flights, air passengers and flight personnel are exposed to space ionizing radiation. At the same time, the level of space ionizing radiation at the used heights of flights can significantly exceed the permissible norms, for instance, by 20-25 times. As a result, both frequent flyers and aviation personnel get a highly negative long-term impact on their body and immune system.

Our article will allow each person to understand the possible risks for themselves in the case of frequent flights and what is more important - to take a due care to minimize the damage to their health and the health of people around during the flights of civil aviation airlines.

1. Introduction and the problem of space radiation

When getting on board, people usually do not think that something can disturb tem during the flight except thunderstorms or turbulence zones at the standard flight corridor of the civil aviation - altitudes of 10-12 km.

As is known, at the end of the last century, civil aviation used lower corridors for the flights - altitudes of 6,0 - 8,0 km above the ground surface. But the modern requirements of the ecological situation for the noise of aircraft engines, its emissions, as well as fuel economy per flight mile, made the pilots to fly away from the ground, closer to the stars due to less air resistance during the flights and financial optimization of passengers’ carriage.

2. Above only stars

During each flight around the world, I did not miss the opportunity to test DO-RA Project developments (http://DO-RA.ru) in the field of environmental monitoring. In particular – I took the measurements of the level of ionizing radiation with DO-RA device. As a result, I discovered the following features of the flights: 

- During the take-off of the aircraft in Chambery, France the radiation background was only 0.10 mSv/ h.

- At the altitude of 3,000 m the background radiation fluctuated between 0.15-0.18 mSv/h.

- At the altitude of 6,000 m the level of background radiation was within 0.30-0.34 mSv/h.

- At the altitude of 8.800 m the level of background radiation was already 0.72-0.76 mSv/h.

- At the altitude of 10.100 m the level of background radiation rose to 1.02-1.12 mSv/h.

- Finally, at the maximum height of the route, namely at the height of 10.700 m the background radiation was 1.22-1.35 mSv/h.

- When landing in Moscow, Domodedovo airport, all measured data on radiation background was confirmed with 100 % accuracy at the same heights.

It turns out that despite day flights are very comfortable for passengers in terms of biological clock and schedule, they expose our body to increased radiation level in comparison with night flights. Geographical direction of the flight does not make sense in this case. The reason for this is excessive cosmic and solar radiation, as well as more discharged air, and, as a result, less effective natural protection from matter particles.

In order not avoid misinformation and not to fall into the trap of my own delusions, this paper will provide examples available on open sources, which can open our eyes to the ionizing radiation which facing us every day and attacking us during the air flights. As is known, humans do not have any sense organs which can identify radiation in order to take necessary measures to reduce its harmful impact on the body and prevent future contact with dangerous radioactive environment.

Remember the saying: "Knowledge is power." The ignorance of the harmful impact of ionizing radiation on the human body, do not free us from its negative effects!

3. Cosmic rays and solar radiation

It is considered that cosmic radiation is ionizing radiation continuously falling on the surface of the Earth from the global space. It is formed in the Earth's atmosphere as a result of the interaction between radiation air components’ atoms.

There are two types of the cosmic rays - primary and secondary. Primary cosmic radiation (CR-1) is a stream of elementary particles that fall on the Earth's surface from space. It occurs due to the eruption and evaporation of matter from the surface of stars and nebula of space. CR-1 consists of protons (92%), alpha particles (7%), isotopes of lithium, beryllium, boron, carbon, nitrogen, oxygen, etc. (1%). Primary cosmic radiation (CR-1) is characterized by high penetrating ability.

Furthermore, cosmic radiation is divided into the following types by origin: (i) extragalactic, (ii) galactic and (iii) solar.

Most of the primary cosmic radiation occurs within our Galaxy, its energy is extremely high - up to 1019 eV.

Solar radiation occurs mainly in solar flares, which occur with Sun’s 11-year Solar Cycle. Its energy does not exceed 40 MeV. This does not lead to a noticeable increase in the radiation dose level on the Earth's surface.

The average energy of cosmic rays is 1010 eV, so they are detrimental to any living thing. The atmosphere serves as a kind of shield that protects biological objects from the effects of cosmic particles, and only a few particles can reach the surface of the Earth.

The interaction of cosmic particles with atoms of elements in the atmosphere generates secondary cosmic radiation (CR-2). It consists of mesons, electrons, positrons, protons, neutrons, gamma quanta, i.e. almost all currently known particles. 

Primary cosmic rays burst into the atmosphere and gradually lose their energy, wasting it on numerous collisions with nucleus of air atoms. As a result, we get the fragments, acquiring part of the primary particle’s energy. These fragments become factors of ionization, which destroy and ionize other atoms of the air gases, in other words, they turn into secondary cosmic radiation particles (CR-2). 

CR-2 arises as a result of electron-photon and electron-nuclear interactions. In the electron-photon process, the charged particle interacts with the field of the atom's nucleus, generating photons that form pairs of electrons and positrons. These particles, in turn, cause the appearance of new photons. The electron-nuclear process is caused by the interaction of primary particles with the nucleus of air atoms whose energy is not less than 3x109 eV. There is a number of new particles – mesons, protons, neutrons as a result of this interaction. Secondary cosmic radiation reaches its maximum level at the altitude of 20-30 km, at the lower altitudes the processes of CR-2 absorption prevail over the processes of its formation.

The intensity of cosmic radiation depends on the latitude and altitude. Since the cosmic rays are mainly charged particles, they deviate in a magnetic field in the area above the equator and gathered in the form of craters in the poles areas. Only particles with low energy are able to reach the Earth's surface in the polar regions (no need to overcome the magnetic field). Therefore, the intensity of cosmic radiation at the poles increases due to these rays. In the Equatorial region, only particles that have maximum energies are able to overcome the deflection effect of the magnetic field and reach the surface.

The average dose rate of cosmic radiation of the inhabitants of the Earth is approximately 0.3 mSv/year, but on the level of London-Moscow-New York it reaches 0.5 mSv / year.

3.1. Units of ionizing radiation measurement

Equivalent dose (two units):

REM – is the roentgen equivalent man (in some sources – RAD radiation absorbed dose). It is a unit of equivalent dose, effective dose, and committed dose which are measures of the health effect of low levels of ionizing radiation on the human body. Generally:

1 REM = 1 RAD* K = 100 erg / g * K = 0.01 Gray * K = 0.01 J/kg * K = 0.01 Sievert

At the coefficient of radiation quality K=1, that is, for x-ray, gamma, beta radiation, electrons and positrons, 1 REM corresponds to the equivalent dose of 1 RAD.

1 REM = 1 RAD = 100 ergs / g = 0.01 Gray = 0.01 j / kg = 0.01 Sievert

The following fact should be particularly noted. Back in the '50s it was found that if the exposure dose in 1 xu air absorbs 83.8-88.0 erg/g (physical equivalent of x-ray), the biological tissue absorbs 93-95 erg/g (biological equivalent of x-ray). Therefore, it turns out that in the evaluation of doses can be considered (with minimal error), that the exposure dose of 1 x - ray for biological tissue corresponds (equivalent) to absorbed dose of 1 rad and equivalent dose of 1 rem (at K=1). Roughly speaking, 1R, 1 rad and 1 rem – all these units are equivalent to each other.

Sievert (SV) is a derived unit of ionizing radiation dose in the International System of Units (SI) and is a measure of the health effect of low levels of ionizing radiation on the human body. 1 SV compared to the physical quantity absorbed dose measured by the unit Gray (Gy). 

In General: 1 SV = 1 Gy. K = 1 j / kg. K = 100 RAD K = 100 REM 

When K=1 (for x-rays, gamma-rays, beta-radiation, electrons and positrons) 1 SV corresponds to the absorbed dose of 1 Gy: 1 SV = 1 Gy = 1 j/kg = 100 rad = 100 rem.

For the purposes of routine radiation protection, it is desirable to characterize the potential irradiation of individuals in terms of a single dose equivalent quantity that would exist in a phantom approximating the human body. Ambient dose equivalent, H*(d), was defined in ICRU Report 51 as the dose equivalent that would be produced by an expanded and aligned radiation field at a depth d in the ICRU sphere. The recommended reference depths are 10 mm for strongly penetrating radiation and 0.07 mm for weakly penetrating radiation, respectively. As an operational quantity in radiation protection, H*(d) shall serve as a conservative and directly measurable estimate of protection quantities, e.g. effective dose E, which in turn are intended to give an indication of the risk associated with radiation exposure. The situation attains increased complexity in radiation environments being composed of a variety of charged and uncharged particles in a broad energetic spectrum. Radiation fields of similarly complex nature are encountered onboard aircraft and in space.

In conclusion, once again we recall that for x-ray, gamma and beta radiation, electrons and positrons, the values of x-ray, RAD and REM, as well as (separately) the values of Gray and Sievert are equal in the evaluation of human radiation exposure. 

3.2. Radiation Safety Norms - NRB-99/2009

Completing an excursion into the physics of the process, we would like to note that due to the active and negative effect of ionizing radiation on the human body and its systems (including immune system), special radiation standards for the flight personnel have been introduced in aviation. These rules limit the flights of the aircraft crew at the rate of maximum 80 flight hours per month, maximum 240 flight hours per quarter and maximum 800 flight hours per year per person.

These flight time norms are taken from the Order of the Ministry of Transport of the Russian Federation No. 139 of November 21, 2015, which is drafted in accordance with  the ICAO International Standards and Recommended Practices (SARPs), paragraph 7.6: "The standards of flight and service flight time for the flight crew members are determined by the standards of the State Aviation Agencies of the countries participants of the ICAO". However, such an hourly counting of the flight hours is now quite an archaic and vicious control system for the flight crew members and that's why.

It is one thing to fly parallel to the equator over the most populated European or Asian continents and quite another thing to make air travel across the poles. And even more so, it is problematic for the health to fly in the period of solar storms. At such moments, when flying, the power of the equivalent dose of the flight crew may differ significantly and do not match with the real norms of the average flight hours.

General health effects of cosmic radiation on different levels of the human body are shown at Figure 3.

During the existence of the radiology science, studying the impact of ionizing radiation on the human body and animals, revealed long-term and reliable statistics on the effects of radiation, expressed in the risks of disease of certain human organs.

The data on disease risks is taken from the official document - Radiation Safety Norms NRB 99/2009 (see Figure 4).

3.3. Civil Aviation Flights Statistics  

International civil aviation statistics provide the following numbers. In 2016, the world aviation transported 3.7 billion passengers, with all airlines of the world committed 10 billion flight hours (ICAO and ATOR statistics). There are civil flights growth forecasts by 4.6% per year until 2034 (UAC data). Although even in 2016 air transportation increased by 6% (ICAO and ATOR statistics).

In 2017, a record number of passengers were transported on regular flights worldwide – more than 4 billion people, which is on 7% higher than in 2016, when there was also a significant increase in relation to the previous period.

At the same time, there are more than 70 million people flying more than 30 times per year according to the ICAO statistics of frequent flyers. In this regard, it can be confidently argued that the market potential of personal radiation monitoring is quite huge and ready for steady and stable growth.

4. DO-RA Technologies:

Personal Radiation Dosimeter for the Flight Crew:

•    Matrix, solid state detectors of radiation with the PIN diode structure
•    Electronics reading based on discrete components or ASIC chip
•    The device has a Wireless Communications Transfer Protocol
•    Software for the various operational systems
•    Design documentation in international IPC format
•    All devices are combined into a single system based on a server solution

DO-RA.Avia Basic Technical Characteristics:

Dimensions (WxDxH), mm: 29.1 x 7 x 62
Operating Temperatures: From 0 to + 55ºС
Sensor Type: Self-generated silicon detector DoRaSi
Gamma and Beta radiation detection: Detected
Maximum error: +/‐10% after 60 seconds of measuring
Data Transfer Interface: Bluetooth low energy (BLE)
Supported mobile operating systems: Apple iOS, Google Android 2.x, 3.x,4.x, WP, Java ME; а также ОС: Windows, Linux, Mac OS.

DO-RA Project Server Solution:

A prototype of the server component for the DO-RA.Avia device software was created;
Keeping records of the number of users;
Maintenance of the system operation Protocol (self-monitoring);
Self-diagnostics, including control of the stored data volume, time and load characteristics control, the number of processed requests, the number of erroneous requests, etc.;
Receiving data from registered mobile devices with reference to coordinates, heights and time of measurement;
Long-term storage of measurement results;
Updating the map of radiation monitoring data;
Providing data monitoring system in the form of maps;
Provision of REST API to external information systems for access to data collection and storage systems, and also data processing system;

• More than 89 patents for inventions and utility models, certificates for software      codes, including: Russia, EurAsEC, USA, Japan, Korea, China, India, EU

• Russian Patents: RU № 109625; 124101; 116296; 116725; 117226; 2484554; 133943; 136194; 140489; 88973; 156901; 156906; 156907; 145480; 2545502; 159972; 125008; 126484; 2575939; 167308

• International Patents: № 025350; 74126; 14797; US 9547089 B2; US 8738077 B2; Korean: 20-0479248; CN 2033537453 U; JP 3189486