Open access peer-reviewed chapter

Gamma Background Radiations and Measurements with Applications

By Lubna A. Al-Asadi

Submitted: September 6th 2018Reviewed: December 21st 2018Published: February 27th 2019

DOI: 10.5772/intechopen.83721

Downloaded: 453

Abstract

This chapter deals with gamma background radiation that is exposed to two major natural sources: normal sources that are earthly gamma rays and astronomical rays. Earthbound gamma rays from radionuclide elements such as thorium, potassium, and uranium. Also, in building and enhancing materials such as medical plants, building purposes, some vegetables and fruits commonly used in markets and soil. The measurements of gamma background radiation differ according to the purpose. So, there are many instruments used such as HPGe detector, NaI (TI) detector, CR-39, a dosimeter, and SSNDT detector. This research will explain in detail the studies and the mechanism for each detector and how it works and the application (practical) studies for each one. The purpose of calculating gamma background radiation is to be in the safe side for human being according to the international union specified with a standard limitation of world average value or with a specific value ranged (standard values) according to the case study in medical, food, or building materials.

Keywords

  • terrestrial gamma rays
  • natural gamma ray
  • background radiation
  • detectors
  • annual effective dose
  • absorbed dose

1. Introduction

How do γ-rays compare with other types of radiation? “Radiation” in common language describes “energy packages” that travel on straight paths. “Electromagnetic radiation” is characterized by variations of electric and magnetic fields in space and time. Another type of “radiation” is “cosmic rays,” very energetic particles discovered early in the twentieth century in the upper atmosphere of the Earth and known to pervade interstellar space. These particles are called “cosmic radiation” because with their high energies they propagate at the speed of light and in certain aspects behave like photons of similar energies [1].

Gamma radiation represents the most energetic part of the electromagnetic spectrum ( Figure 1 ). Therefore, it is natural that it provides information about the liveliest procedures and wonders in the universe [2].

Figure 1.

The electromagnetic spectrum from radio to γ-ray energies. The electromagnetic radiation can be characterized by its photon energy (measured in eV), by its frequency (measured in Hz) or by its wavelength (measured in m) [2].

In general, there are three noteworthy sources: earthly radiation, grandiose radiation, and interior radiation due to the admission of regular radionuclides through inward breath (for the most part radon) and ingestion. Additionally, the most three radionuclide components are thorium (232Th), potassium (40K), and uranium (238U). Natural radiation sources consolidate the ground, rocks, air, building materials, and drinking water supplies. Big amount of radiation rises up out of sun situated, galactic and extragalactic transmissions and contains decidedly charged particles, muons, neutrons, and gamma radiation.

Inward radiation is in our body because of what we eat and drink and the air we unwind. Common radiation in a general sense relies upon topographical and geological conditions. In this way, the portion ratios of both enormous and earthbound gamma radiation will be found to vary depending upon where the estimations are made [3, 4, 5].

As the research shows the relationship between the gamma-ray and living beings and all gamma radiation in the earth, it will explain in detail the mechanisms (according to the user of the detector) to calculate gamma background radiation and the measurements depending on the international standard values.

2. Methods of measuring gamma rays

This section explains the most common detectors used in the measurement of gamma background radiation and equipped with the international practical recent researches, to let the researchers who have worked in this field have the basic knowledge on these devices by knowing the mechanism of how they work and how to calculate gamma background radiation.

2.1 Radiation dosimetry

A radiation dosimeter is a gadget, instrument, or framework that measures or assesses specifically or in a roundabout way, the amounts presentation, KERMA, proportional portion, or when they again their time auxiliaries (rates), or related amounts of ionizing radiation. A dosimeter close by its scrutinize is insinuated as a dosimetry structure.

Estimation of a dosimetric aggregate is the course toward finding the respect of the total likely utilizing dosimetry frameworks. The delayed consequence of estimation is the estimation of a dosimetric aggregate imparted as the aftereffect of a numerical regard and a reasonable unit. To fill in as a radiation dosimeter, the dosimeter must have no short of what one physical property that is a component of the intentional dosimetric sum and that can be used for radiation dosimetry with the real arrangement. With the ultimate objective to be significant, radiation dosimeters must show a couple of appealing characteristics.

For instance, in radiotherapy, correct information of both the consumed portion of water at a predefined point and its spatial appropriation are of significance, also the likelihood of determining the portion to an organ of enthusiasm for the patient [6]. In radiation, preparing dosimetry is utilized to evaluate the vitality kept in a material or consumed by a human from radiation sources.

Diverse dosimetry frameworks are utilized for various purposes in industry and research light offices, which have distinctive prerequisites for portion conclusions. Radiation wellbeing norms and issues including the radiation safety of people against radiation presentation have their very own dosimetry metrology.

Radiation dosimeters and dosimetry frameworks come in numerous shapes and structures and they depend on various physical impacts for capacity and readout of the dosimetric flag. The below table demonstrates the most regularly utilized of dosimetric frameworks, and the qualities and shortcomings of these four dosimeters are outlined. The four most commonly used radiation dosimeters are [6]:

  • Ionization chambers

  • Radiographic films

  • TLDs

  • Diodes

Dosimetry typeAdvantageDisadvantage
Ionization chambersAccurate and precise.
Recommended for beam calibration.
Necessary corrections well understood.
Instant readout.
Connecting cables required.
High voltage supply required.
Many corrections required for high energy beam dosimetry.
Radiographic films(2-D) spatial goals.
Thin: does not irritate the pillar.
Darkroom and preparing offices required.
Preparing hard to control variety among movies and clumps.
Needs legitimate alignment against ionization chamber estimations.
Energy reliance issues can’t be utilized for pillar alignment.
TLDsSmall in size: point portion estimations conceivable.
Numerous TLDs can be uncovered in a solitary presentation.
Accessible in different structures such as some similar tissue identical.
Not costly.
Flag deleted amid readout.
Simple to lose perusing.
No moment readout.
Precise outcomes require care readout and alignment tedious.
Not suggested for shaft calibration.
DiodesLittle size.
High affectability.
Moment readout.
No outer inclination voltage basic instrumentation.
Requires partner joins Variability of alteration with temperature.
Change in affectability with the aggregated portion.
Uncommon consideration expected to guarantee consistency of reaction.
Can’t be utilized for pillar adjustment.

Radiation dosimetry is a part of physical science investigating diverse strategies for the quantitative assurance of vitality, which is stored in a given material by ionizing radiation, either through an immediate or aberrant presentation. Dosimetry manages conclusions and computations of amounts (portion) that depict the vitality ingested in a material and to some degree its rate of the statement (portion rate). Dosimetry conclusions that are performed by presenting a dosimeter to a radiation source help in assessing the radiation-prompted impacts, physical, substance, and additionally organic, on a lighted material [7]. Figure 2 shows a Science Photo Library/Getty Images [8].

Figure 2.

Science Photo Library/Getty Images [8].

Know the most recent research to calculate gamma background radiation is measurements of gamma background radiation in Lorestan, Iran.

The researcher used a G.M. detector (RDS-110) “Inspector Alert model RAP RS1, S.E. international, Inc, USA”. The outcome demonstrates the normal yearly powerful portion for gamma base radiation in Lorestan area has been 0.72 mSv, with the scope of 0.3–0.6 mSv which was more than the worldwide esteem (0.48 mSv). A poor coefficient relationship in-between was noticed elevating and retaining portion rates [9].

Another research study used the same device and the same properties. Indoor and outdoor absorbed dose rates were measured in the select region of AL-Qizweenia Najaf in Iraq [10]. Many studies in the gamma field of background radiation were conducted in different cities of Iraq [11, 12, 13]. All values of these studies compared with limitation of world average values.

2.2 Radiographic films (NaI scintillation detector)

There was an expansive glitter phenomenon in 1948 which was accounted for. It caused by including a follow amount of thallium (Tl) into a precious stone of sodium iodide (NaI). This identifier, in which sodium iodide (NaI) was utilized for radiation estimations, was based on the fact that recently it had been produced by HORIBA. They had the advancement of the NaI(Tl) plate for gamma cameras began during the 1970s.

In the first place, gems with breadths of 1–3 inches were utilized as indicators for atomic material science tests, natural radiation estimations at atomic power plants, or radioimmunoassay. Furthermore, mosaic-type precious stones were likewise created to relate to vast estimated gems notwithstanding the gems with a distance across of around 5 inches. After the expansive estimated gamma camera was created, bigger and bigger precious stones have been requested each year, and researchers have been making a decent attempt to get ever bigger measured NaI(Tl) gems as of late, and Figure 3 shows atypical scintillation detector [14].

Figure 3.

Atypical scintillation detector [14].

An elective strategy for assurance of exercises of regular, techno genic, and aftermath radionuclide in natural examples was proposed. The strategy utilized a broadly accessible shine spectrometer and depended on the disintegration of tests’ γ-spectra into ghastly segments of discrete radionuclide bunches with the assistance of standard sources. The technique was tested on water, soil, and coal which could be effectively utilized in field (endeavor) conditions (without fluid nitrogen for the indicator cooling) [15].

There were many local and international studies used NaI(Tl) detector to evaluate natural or terrestrial of radionuclide or gamma background radiation with a difference of accuracy and efficiency of the device and sometimes equipped with a software program of the trace elements.

In 2013, a nearby report discusses uranium (238U), thorium (232Th), and potassium (40K) with the explicit movement (10) in a few types of vegetables that is accessible at the market in Iraq. Tests had been estimated, and inner risk file, radium identical, and the yearly compelling portion of (40K) in all examples were resolved. The gamma spectrometry methodology with a NaI(Tl) pointer was used for radiometric estimations, outcomes were contrasted and worldwide prescribed qualities and were observed to be inside the global dimension [16].

An investigation was conducted on radionuclides (226Ra, 232Th, and 40K) of natural radioactivity estimations and assessment of radiological hazards in the silt of Oguta Lake, South East Nigeria. NaI(Tl) indicator “(show: Bicron, Pre-intensifier model:2001, Amplifier model:2020, ADC model:8075, HVPS model:3105)” was utilized for the gamma-beam spectrometry estimations. The identifier has a goal of 8% at 0.665 MeV line of 137Cs, which is equipped for recognizing the gamma-beam energies of the radionuclides of enthusiasm for this examination. The investigation could fill in as critical radiometric pattern information whereupon future epidemiological examinations and ecological observing activities could be based [17].

Another examination enduring gamma producers in biscuit samples expired in Iraq, estimated the common radioactivity couple to seemingly perpetual gamma producers in children roll by gamma spectroscopy and appraisal radiation risk records which are the radium comparable action, the delegate of gamma level file, the interior danger file, and yearly powerful portion in kids. The gamma spectrum from each sample was recorded using detector NaI(Tl), and the volume of the crystal is (“3 × 3”), a PC-based multichannel analyzer (4096 channel) and processed using the MAESTRO-32 software. The estimations of eexpress activity, radiation risk records, and a yearly viable portion in all examples in this investigation are discovered lower than the overall middle incentive for all gatherings. Along these lines, these qualities are observed to be protected [18].

Three types of research are in the same field (used NaI detector). First one is in Kütahya, Turkey. The examination of common radioactivity from 238U, 232Th, and 40K in 357 soil tests gathered from territory of Kütahya was completed utilizing a NaI(Tl) gamma-beam spectroscopy. Explicit exercises of 238U, 232Th, and 40K in the dirt examples were assessed. The locator was coupled to a full-featured 16 K channel fused multichannel analyzer “(Canberra DSA-1000).” It is joined with a PC for getting an examination and with reasonable programming “(Genie 2000).”

The identifier was covered in a 0.5 cm thickness lead shield, giving a disguise of the establishment gamma-bar radiation present in the exploration office. The NaI(Tl) gamma-bar spectrometer has high efficiency, and in a similar manner, it might be used for the customary radioactivity. The outcomes acquired in this examination were analyzed inside the cutoff points of values gotten in different urban areas of Turkey, those in different nations [19].

Second research estimated normal radioactivity in chosen tests of therapeutic plants in Iraq, where characteristic dimensions of radiation in some chosen therapeutic plants existing in the Iraqi stores were assessed to decide any action fixation, radium comparable, and inner risk file due to the radionuclide, of 238U, 232Th, and in addition 40K, which happens normally. The movement fixation is recognized by gamma-beam spectroscopy and NaI(Tl). Estimations are done by embracing frameworks of gamma spectrometry from ORTEC, furnished with a high productivity sparkle indicator, a NaI(Tl) locator of (3″ × 3″) precious stone measurement, with goals 9.2% for 137Cs (661.7 keV). A lead shield with a thickness of (10 cm) was put around the finder to decrease the foundation, with a 0.3 cm layer of copper to debilitate X-rays discharged by the lead shield. The spectra were seen disconnected utilizing the ORTEC Maestro-32 information obtaining and examination framework. Regular radionuclides and development of the radium similar to the remedial plant tests were far underneath the world for the ingestion of typically happening radionuclide, as given in UNSCEAR 2000 report [20].

Third research in some vegetables and fruits commonly used in Najaf Governorate, Iraq, determined the natural radioactivity levels. The points of the present work were to gauge the explicit action and yearly compelling portion because of the admission of vegetables and organic products gathered from the nearby market in Najaf governorate. Characteristic radioactivity was estimated in tests utilizing gamma beam spectrometer. Gamma-ray spectroscopy with scintillation detector NaI(TI) from ORTEC had an active area of “3 × 3” inches, the efficiency of 4.6% at the 662 KeV, and energy resolution 7.9%. The qualities found for explicit action and the yearly powerful portion in all examples in this investigation were lower than overall middle qualities for all gatherings as indicated by UNSCEAR (2000) and ICRP (1996) individually; subsequently, these qualities are observed to be sheltered [21].

Also, a study in Turkey for the three radionuclide elements (226Ra, 232 Th, and 40K) had been made in some granite samples. The action grouping of primordial radionuclides in rock tests was assessed by utilizing (3 × 3) NaI(Tl) indicator-based gamma-beam spectrometry. This gamma spectrometer has vitality goals 8% for 662 keV and the relative checking productivity about 20%. It was critical that the productivity adjustment of the framework ought to be made before estimation for the right outcome. Estimation of radioactivity for, 14 various types of stone examples have been breaking down for their regular radioactivity content. The end was: the 40K action focus levels in stone examples in these investigations were lower than fixation estimations of various examinations on the planet. A few examples and other stone examples were not observed to be reasonable for utilizing in the human life regions due to every single radiological incentive in these examples are higher than CLV [22].

2.3 TLD detector (thermoluminescence detector)

Roentgen in 1928 was held onto as a unit to describe radiation introduction. Roentgen evaluates the number of electrons made in air, yet not the genuine damage following in a man.

In 1953, a unit known as a rad (100 ergs g−1) was grasped to portray the proportion of essentialness spared in a material. Clearly, it was found that different sorts of radiation affected the tissue in the body all of a sudden. Another unit was made to address this, known as a rem. A rem is proportionate to a rad duplicated by a factor known as a “Quality Factor” (Q) which numerically portrays the relative trademark impact of the express kind of radiation. As these new units of measure were made and executed, new radiation materials and exposure instruments were delivered with the objective that contradictory exposures and doses could be accurately evaluated [23].

Although extremely accurate active radiation detectors are now available, TLDs are small, inexpensive, and if the correct material is chosen, tissue equivalent. They can be used to detect photons, beta particles, and slow neutrons, and with appropriate filters, they can be used to determine the shallow and deep dose. Their biggest advantage is long-term deplorability, possible due to a power source being unnecessary until readout. This allows time-efficient monitoring of typically uninhabited areas. In order to ensure accurate results from long deployments in diverse interior and exterior environments, various aspects of their performance must be examined. This work serves to improve the effectiveness of TLD systems by analyzing several factors which may affect the sensitivity and precision of TLD measurements, as well as determining a practical minimum detectable dose incorporating those factors.

TLDs must be individually calibrated, meaning that the amount of signal response to a known dose must be measured before use. The light response to doses generally between 0.1 mGy and 10 Gy, but varying by material, has a two linear relationship with dose. This makes calibration at only one dose necessary if staying within the linear range [24]. Figure 4 below shows the thermoluminescence detector (model THERMO SCIENTIFIC 4500 TLD READER) in the laboratory at Ankara University, Institute of nuclear sciences [25].

Figure 4.

THERMO SCIENTIFIC 4500 TLD READER [25].

Some examples of modern researches will be taken. Researches of detector will show it had much application with different branches in physical science. First one in network communication in which the point is to seek after an ordinary free quality review in Czech radiotherapy focuses and to help state supervision. The results appears to be that there are 34 radiotherapy focuses in the Czech Republic. They experience the essential method of the TLD review routinely at regular intervals.

On the off chance that an inside demonstrates a deviation outside the acknowledgment level, it is evaluated more frequently. Step by step, a large portion of the checked shafts conform to the acknowledgment level.

Results were for the most part inside as far as possible for the estimations on-hub, though for off-hub focuses they fell past the limit all the more oftentimes, particularly for set-ups with in-homogeneities, diagonal occurrence, and wedges.

The outcomes demonstrate the significance of the national TLD quality affirmation arrange. It has added to the enhancement of clinical dosimetry in the Czech Republic. What’s more, it causes administrative specialist to screen successfully and consistently radiotherapy focuses [26].

An exploration in therapeutic material science including patients and apparition dosimetry in the two cases, thermoluminescence dosimetry (TLD) is the most suitable strategy for estimating the assimilated portion. In this chapter, thermoluminescence wonder and in addition the utilization of TLD in radiodiagnosis and radiotherapy for in vivo or in apparition estimations is talked about. A few aftereffects of estimations made in radiotherapy and radio diagnosis utilizing natively constructed LiF: Mg, Cu, P + PTFE TLD are exhibited [27].

In nuclear atomic material science, an examination in the robust assurance of successful nuclear numbers for electron together with “TLD-100 and TLD-100H thermoluminescent dosimeters,” lithium fluoride thermoluminescent dosimeters (TLD) are frequently not completed for clinical dosimetry. The little physical enormity of TLDs makes them applicable, for instance, little field estimation, in vivo dosimetry, and estimation of out-of-field bits of essential structures. The most exhaustively used TLD can’t avoid being “TLD-100 (LiF: Mg, Ti),” and for applications requiring higher affectability to low-parcels, TLD-100H (LiF: Mg, Cu, P) is consistently used. The radiological properties of these TLDs are along these lines of significant interest. All of a sudden, in this examination, convincing atomic numbers for radiative, collisional, and mean electron association frames is resolved for “TLD-100 and TLD-100H” dosimeters over the essential expansion of 1 keV–100 MeV. This is applied by using a solid, essentialness subordinate system for calculation instead of normal power-law approximations. The effect of dopant obsessions and unwanted impacts is further analyzed. The two TLDs show relative convincing atomic numbers, generally ranging from 5.77 to 6.51. Differentiations rising up out of the particular dopants are most enunciated in low-imperativeness radiative effects. The TLDs have atomic numbers around (1.48–2.06) events than that of water [28].

Measurement of computed tomography dose profile with pitch variation uses Gafchromic XR-QA2 and thermoluminescence dosimeter (TLD). This examination was meant to point the examples of portion profile on a grown-up and pediatric head filter. They thought about estimation depended on portion profile along the z-hub turn at peripheries and focus apparition with an assortment of the pitch, that is, 0.75, 1, and 1.5 for grown-up and pediatric head convention, keeping whatever is left of the sweep parameters steady.

Estimations were performed on homogeneous, round, and void PMMA ghost with widths of 16 and 10 cm utilizing XR-QA2 Gafchromic film and TLD as dosimeters. The estimation result showed a diminishing in the part about half and 47% for grown-up and pediatric head check with the advancement of pitch. Part profile for adult and pediatric head channel traditions has configuration twist with the most outrageous bit in the inside and inclination of symmetry near the edges, with difference in the dimension length along z-center point bearing incomprehension to the estimation position in the nebulous vision [29].

A research related with nuclear physics was unfolding neutron spectra from the simulated response of thermoluminescence dosimeters, and neutron spectrometry utilizing a solitary circle containing dosimeters has been produced as of late, as a powerful swap for Bonner circle spectrometry. The purpose of the examination is spreading out the neutron essentialness spectra using the GRNN fake neural framework, from the response of thermoluminescence dosimeters, TLDs, arranged inside a polyethylene circle. The spectrometer was reproduced using MCNP5.

TLD-600 and TLD-700 dosimeters were replicated in different positions all over. By then, the GRNN was used for neutron spectrum gauge, using the TLDs’ readings. Examination of spectra foreseen by the framework with real spectra shows that the single-circle dosimeter is an incredible instrument in spreading out neutron spectra [30].

Solid state physic took apart with thermoluminescence detector, preliminary studies of thermoluminescence dosimeter “(TLD) CaSO4: Dy Synthesis. thermoluminescence dosimeter (TLD) CaSO4: Dy” was orchestrated by coprecipitation.

The TLD was seen after radiation introduction to Strontium-90. The thermoluminescence drive was scrutinized using a TLD Reader Harshaw 3500. The thermoluminescent response obtained was 59.29 nC. By then, refortifying was driven with the temperature vacillated at 700, 800, and 900°C. The thermoluminescent control got at temperatures of 700–900°C was 66.12, 169.45, and 552.37 nC independently. The affectability of the TLD extended in light of the retoughening temperature rise. Despite viewing the thermoluminescence properties, a relationship was made between the TLD got from this attempt distinctive things with a current TLD in the market. At long last, likewise, the gleam bend attributes of the TLD were watched [31].

The U.S. Naval force utilizes the “Harshaw 8840/8841 dosimetric (DT-702/PD)” framework, which utilizes LiF: Mg, Cu, P thermoluminescent dosimeters (TLDs), created and delivered by Thermo Fisher Scientific (TFS). The dosimeter comprises four LiF: Mg, Cu, P components, mounted in Teflon on an aluminum card and put in a possessor made from plastic. The possessor consists of an interesting channel for each chip made of copper.

The Naval Dosimetry Center (NDC) has created and tried another nondamaging method, which empowers the check and the assessment of installed channels in the possessors. Testing depends on weakening estimations of low-vitality radiation transmitted through each channel in an agent test gathering of possessors to confirm that right channel type and thickness are available. The deliberate reaction proportions are then contrasted and the normal reaction proportions. Moreover, every component’s deliberate reaction is contrasted with the mean reaction of the gathering. The test was organized and endeavored to recognize basic singularities, for instance, missing copper or tin channels, twofold copper or twofold tin channels, or diverse discords that may influence TLD response extents. In the midst of the execution of the made strategy, testing revealed a possessor with a twofold copper channel. To finish the assessment, the effect of the qualifications on limit testing was destitute down. The examination uncovered disappointments in capacity testing orders III and IV when these dosimeters were edified to high-significance betas [32].

2.4 Diode detector

The diode indicator is the least difficult and most essential type of abundancy tweak, AM locator, and it distinguishes the envelope of the AM flag as shown in Figure 5 . The AM diode locator could be worked only on a diode with couple of different segments, and therefore it is a minimal effort circuit hinder inside a general recipient. Because of its expense and comfort, the AM diode envelope identifier has been broadly utilized for a long time in transistor compact radios.

Figure 5.

Circuit of an envelope locator as utilized in an AM radio collector [33].

2.4.1 AM diode detection process

In changing the RF hail, the AM diode discoverer gives a yield proportionate to the envelope of one part of the banner, and this implies an envelope locator. In context of the errand of the diode marker, it may every so often be implied as an envelope discoverer. The moving toward abundancy changed RF hail includes a waveform of both positive and negative going voltages as shown in Figure 6 . Any stable transducer would not respond to that.

Figure 6.

AM diode envelop detection process [33].

The diode envelope discoverer changes the waveform leaving only the positive or negative segment of the waveform. The high repeat part of this is filtered through, normally using a capacitor that outlines the low pass channel and suitable “fills” in the high repeat segments, leaving a waveform to which a transducer like two or three earphones or an enhancer could respond to and convert into sound waves.

2.4.2 Focal points and drawbacks of a diode envelope locator

The AM diode envelope discoverer had been viably used to quite a while. The most envelope pointer purposes of intrigue are: ease that means the diode indicator just requires the utilization of a couple of ease parts. This means it is perfect for use in transistor (and valve/vacuum tube) radios utilizing discrete segments, effortlessness means utilizing not a lot of parts, and the diode AM identifier was definitely not hard to complete. It was dependable and did not need any setup, while an envelope identifier inconveniences are:

2.4.2.1 Contortion

As the diode indicator is nondirect, it presents mutilation onto the identified sound flag.

2.4.2.2 Particular blurring

One of the issues a significant part of the time experienced on the short and medium wavebands where the AM transmissions are found is that of express darkening. The diode envelope identifier cannot battle the impacts of this on how some different locators are capable, and therefore, contortion happens when specific blurring happens.

2.4.2.3 Affectability

The diode locator is not as precarious as some remarkable sorts. On the off chance that silicon diodes are utilized, these have a turn-on voltage of around 0.6 volts, and therefore, germanium or Schottky diodes are utilized which have a lower turn-on voltage of around 0.2–0.3 volts. Without a doubt, even with the utilization of the Schottky diode, the diode envelope identifier still experiences a pore estimation of affectability.

The AM diode envelope indicator has been accessible for a long time. Despite the fact that abundancy balance is utilized less nowadays, and different types of AM finder can be effortlessly consolidated into coordinated circuits, the basic diode identifier still has a few points of interest [33].

After a brief explanation about diode detector, some recent applications of diode detector will be discussed.

In remedial material science, in light of the way is that the skin diode is made on a thin epitaxial layer and bundled utilizing the “drop-in” advancement. It was portrayed comparably as rate hugeness isolate, segment linearity, and section rate reliance and benchmarked against the Attix ionization chamber. The reaction of the skin diode in the enhancement zone of the rate importance divide touch of a 6 MV clinical photon bar was explored. The radiation hardness of the skin diode up to an amassed bit of 80 kGy using photons from a Co-60 gamma source was surveyed [34].

Another application in the same field is evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery; the little fields and sharp angles regularly experienced in proton radiosurgery require high spatial goal dosimetric estimations, particularly underneath 1–2 cm measurements. The radiochromic film gives high goals; however, it requires postprocessing and unique taking care of. Promising choices are diode identifiers with little delicate volumes (SV) that are able to do high goals and continuous portion obtaining.

In this investigation, the analyst assessed the PTW PR60020 proton dosimetry diode utilizing radiation fields and shaft energies pertinent to radiosurgery applications [35].

Schottky diode is well know; therefore, we have given examples. The first one is calculating the diode junction resistance variations with RF power of a series Schottky diode detector. Based on the Ritz-Galerkin method, this research provides a simple formula that can be used to calculate the differential input impedance and frequency response of a diode detector. Calculated results are presented for several circuit configurations that are confirmed by ADS [36].

The second example is high-resolution Schottky CdTe diode detector, with a Schottky intersection created on the Te face of a top-notch CdTe semiconductor by dissipating indium, and they have possessed the capacity to accomplish a CdTe diode including high vitality goals. The identifiers demonstrate the best execution when they utilize a moderately thin locator of 1 mm. The high vitality goals of the CdTe diode are exceptionally alluring for hard X-beam and gamma-beam recognition. Particularly, an extensive CdTe diode with measurements bigger than 20 × 20 mm can possibly supplant shine locators because of its high ceasing force and vitality goals of 3 keV at 100 keV. Numerous ideas dependent on high goal CdTe diodes are currently being examined, and model indicators are being created [37].

3. HPGe detector

Semiconductor identifiers are basically strong state analogs of gas-filled ionization chambers. Since the strong indicator materials utilized in semiconductor identifiers are 2000 to multiple times more than gases, they have the much better halting force and are considerably more productive finders for X-rays and γ-rays.

Semiconductor indicators regularly are poor electrical transmitters; when they were ionized by an ionizing radiation event, the electrical charge delivered could be gathered by an outer connected voltage, for what its worth with gas-filled locators. This guideline could not be connected utilizing a leading material for the locator (e.g., a square of metal) on the grounds that such a material would direct a lot of current even without ionizing occasions. Protectors (e.g., glass) are not appropriate identifier materials either on the grounds that they don’t lead even within the sight of ionizing radiation. Subsequently, just semiconductor materials can work as “strong ionization chambers.”

The most by and large used semiconductor locator materials are silicon (Si) and germanium (Ge). Even more starting late, cadmium telluride (CdTe) or cadmium zinc telluride (CZT) has been utilized as the major material in insignificant atomic medicine checking and imaging gadgets. One ionization is made per 3–5 eV of radiation importance consumed. By examination, this propelling power for gases (air) is around 34 eV for each ionization. Subsequently, a semiconductor locator not exclusively is more fruitful shield of radiation, in any case, passes on an electrical standard that is around various events more prominent (per unit of radiation centrality ingested) than a gas-filled pioneer. The flag is sufficiently enormous to allow recognizing verification and checking of individual radiation occasions. Also, the proportion of the electrical banner is relating to the proportion of radiation imperativeness acclimatized. Thusly, semiconductor discoverers can be used for essentialness explicit radiation counting [38].

The most advantage of HPGe high purity germanium detectors (HPGe) is the best energy resolution among all detector types. In principle, they work like reverse biased diodes; energy deposition by nuclear radiation causes the flow of a current, which is processed by front-end electronics [39]. Figure 7 shows a geometrical dimension of the investigated detector (mm).

Figure 7.

A geometrical dimension of the investigated detector (mm) [39].

In 2018, many international studies are about gamma background radiation and using HPGe detector. One of these studies is treating illnesses for many years all over the world. The aim of this study is to determine the radioactivity levels in some anti-carcinogenic medicinal plants that are often used to treat illnesses in Turkey.

The analysis of 226Ra, 232Th, 40K, and 137Cs activity concentration of medicinal plants was performed using a high-resolution gamma-ray spectrometer with HpGe detector. Total committed effective dose value due to ingestion was determined as 55.04 μSv y−1 for these medicinal plants and has no risk to public health [40].

A study to analyze natural radioactivity level contents in Nigeria and China and a typical radioactive substance in tiles manufactured in Nigeria and tiles imported from China were evaluated using gamma-shaft spectroscopy. High purity germanium identifier was used to check the combinations of a couple of radioisotopes present in 17 trial of various tiles from Nigeria and China. The mean estimation of annual viable gamma dosages and the lifetime dangers to procure in this examination is not as much as that of the worldwide reference estimation of 370 Bq/kg for the two sorts of tiles [41].

Another place in Nigeria studied building material purpose, which evaluated the activity concentration of natural radionuclides (226Ra, 232Th, and 40K) for fifteen (15) different brands of tile samples, is used for building purposes in Nigeria. The tile samples were analyzed using high purity germanium gamma detector. The deliberate centralizations of these radioactive materials were related with different past outcomes got from comparable tile materials utilized in different nations and observed to be in great concurrence with the global standard, and be that as it may, the tiles are suggested for adornment purposes in Nigeria [42].

A research in Amman calculated hazard indices and annual effective dose due to terrestrial radioactivity in the urban areas of south Amman. The extricated qualities are, by and large, tantamount to the relating ones acquired from different locales in Jordan and different nations and they all fall inside the normal overall reaches. Consequently, the foundation in these regions is actually equivalent to the esteem run of the mill of the upper piece of the Earth’s outside layer. Hence, all the samples investigated can be considered as safe materials for use in building constructions [43].

The radioactivity groupings of 226Ra, 232Th, and 40K in 24 tests of normal and made building materials ordinarily utilized in Bangladesh were estimated utilizing HPGe gamma-beam spectrometer. Outcomes were contrasted and the world normal and furthermore with the detailed information. The radium equal action, the assimilated portion rate, yearly successful portion, outer and inside peril records, gamma file, alpha file, yearly gonadal portion equal, and overabundance lifetime malignancy chance were additionally assessed to assess the potential radiation dangers related with these building materials.

All models under investigation were seen to be inside the recommended prosperity limit and don’t speak to any essential radiation risks. This examination can be used as a sort of viewpoint for more expansive examinations of a comparable subject in future [44].

The radiological risk from building stone interfaces in Jordanian houses was determined depending on gamma-ray spectrometric techniques. Building stone samples collected from seven types mostly used in Jordanian houses have been analyzed for the naturally occurring radioactive radionuclides. Moreover, different radiological hazardous parameters (absorbed dose, annual effective dose equivalent, AGDE, ELCR, and AUI) were calculated. The results were lower than those of published world average values. Also, the obtained values were comparable with the presented data of other building materials used in Jordan [45].

Two researches in 2017, first one is Evaluation of Natural Radioactivity and its Radiation Hazards in Some Building and Decorative Materials in Iraq, 29 examples of various kinds of building materials, for example, blocks, bond, earthenware, rock, marble, paint, mortar, sand, and soil were examined by a gamma spectrometer dependent on HPGe locator. The outcomes demonstrated that all the building materials in Iraq are sheltered with the exception of the materials that utilized as improving materials that must be directed [46].

The second one is in north focal of Nigeria; measurement of the radiation portion dispersion is critical in surveying the wellbeing hazard a populace and fill in as a kind of perspective in archiving changes to ecological radioactivity in soil because of man-made exercises. The mean assimilated portion rate, yearly successful portion, and gamma radiation record assessed were 66.2 nGyh−1, 81.2 μSvy−1, and 1.05 individually which are higher than as far as possible for ordinary foundation radiation. In this manner, it is argued that individuals living in these areas might be presented to higher radiation [47].

There are numerous examinations in Turkey about radioactivity levels and malignancy hazard. Turkey, particularly its northern piece, was one of the nations which were defiled by the Chernobyl mishap. In the Northeastern area of Turkey, there was a city named Rize, which was intensely affected by the Chernobyl atomic mishap.

The action convergences of characteristic (226Ra, 232Th, and 40K) and artificial (137Cs) were estimations in soil tests gathered from 132 distinct focuses in Rize territory of Turkey utilizing gamma spectrometry with HPGe identifier. The open-air assimilated portion rates (D) because of earthbound gamma rays for soil have been determined due to agrarian zone and lived in the encompassing. It is essential to decide foundation radiation level with the end goal to assess the wellbeing dangers.

Yearly viable gamma dosages and the presence dangers of disease were higher than the world’s normal. Besides contrast with the World’s normal, the existence time danger of malignancy is multiplied for a large portion of the territories [48].

In Egypt, south Sinai granite is generally utilized in the development of homes as a building material. It contains the common radionuclides, 238U and 232Th, and their descendants together with 40K. This guarantees the significance of the evaluation of radiation levels and the related radiological dangers to which the populace may be uncovered. Gamma shaft spectra of standard radioactivity from the 238U and 232Th game-plan and from 40K of eight (tending to 40 gathered models) shake tests collected from Saint Katherine district, South Sinai, Egypt, had been assessed utilizing a gamma-column spectrometer with HPGe identifier. From the exploratory and computational work on normal radioactivity of Egyptian shake tests, we can complete the going with:

First, the region from where they collected the granite samples, South Sinai Governorate, Egypt contains 238U, 232Th, and 40K radionuclides with obsessions higher, comparable and lower than beyond what many would consider possible. Second, the radium tantamount activity is not actually beyond what many would consider possible. Thirdly, the danger lists, the dimension lists, and the actors use lists that are not exactly the world set criteria. Fourth, the Clark esteem is equivalent to around five which implies that district from where they took the rock tests isn’t financial for uranium mining and extraction [49].

Southwestern of Nigeria (226Ra, 232Th, and 40K) and artificial (137Cs) were measured using (HPGe) detector (Canberra Industries Inc.). The outdoor absorbed dose rates in the air at about 1.0 m height were estimated from the activity concentrations and dose rate conversion factors for the radionuclides. The annual outdoor effective dose equivalent rates were also estimated for urban and rural areas of the state using the calculated absorbed dose rates in air. The results showed that area named (Igbeti and Eruwa) soils contain the highest level of natural radioactivity, while Egbeda soil contains the lowest level. The study showed that healthy burden caused by natural background radiation from soils on inhabitant area of study is generally low and carried insignificant radiation hazard except for two locations (Igbeti and Eruwa) [50].

A second study in Malaysia 2013, the radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate, and annual effective dose, and also, the mean lifetime dose and lifetime cancer risk for each person living in the area with an average lifetime (70 years). Two strategies have been utilized to assess outer exposures in this examination. The first was a provoke estimation of outside gamma segment rates.

The observation was taken at 497 zones in the Kluang District at 1 m above the ground utilizing two NaI-based gamma locators. The second system depended upon surveyed action revolves around soil tests and the gamma divide (Dc) from the gatherings of 238U, 232Th, and 40K. The advancement groupings of 226Ra, 232Th, and 40K in soil were acquired by utilizing the HPGe gamma spectrometer. The advancement fixations decided for 57 soil tests. The rationale for affirmation of the gamma segment rates from the fixations was gotten a handle on from United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000 [51].

The fundamental goal of this examination is to decide the action centralizations of primordial radionuclides in soil tests gathered from various of studying locale areas in India such as Ramanagara, Tumkur, and Karnataka districts, using gamma bar spectrometry and besides the radiological dangers records identified with based on soil tests. The radiological hazard files of the common radioactivity have been determined and contrasted and the globally affirmed qualities. The convergence of these radionuclides with various sizes and depth of the dirt examples was contemplated. They were found to pursue [52]:

The 232Th and 40K action focus was seen to be marginally higher than the world normal values reported by UNSCEAR (2000). The normal 226Ra fixation in soil tests of the contemplated zone was observed to be like the world normal.

The assessed normal action grouping of 226Ra, 232Th, and 40K in soil tests of those contemplated zones observed to be higher than the Indian normal.

Results acquired had demonstrated radiological dangers, for example, gamma list, radium equal movement, external peril record, and indoor risk list are well inside the world normal esteem. At last, it is presumed that the radiation discharged from the radionuclides present in the dirt of the examination zone doesn’t represent any radiological wellbeing risk to the general population of the zone.

The normal indoor and open-air ingested portion rate for the dirt examples of investigation zone were marginally higher than the world normal estimations of 75 nGy h−1 for indoor what’s more, 59 nGy h−1 for open air.

Results show that ordinary indoor, outdoors amazing part, and a total yearly convincing bit in view of trademark radioactivity of soil tests is lower than the typical national and world endorsed estimation of 1 mSv y−1.

Movement assembly of primordial radionuclides increases with an addition in grain gauge.

Information procured in this examination will fill in as a benchmark for looking over the radiation presentation of the inhabitants.

4. Conclusions

This section manages gamma foundation radiation which uncovered with two noteworthy normal sources; earthly gamma rays and astronomical rays.

Recent studies in building materials, medical plants, building purposes, some vegetables and fruits commonly used in markets, and different soil samples in various countries in the world. The measurements of gamma background radiation differ according to the purpose. Each type of detectors is explained which are: radiographic films (scintillation detector), TLD detector (thermoluminescence detector), diode detector, and HPGe detector. The mechanism for each detector is provided with recently applied researches for the past 10 years, focusing on used gamma background radiations measurements.

Acknowledgments

The author expresses a deep sense of gratitude to Kufa University, Faculty of Science, for providing the scientific support to do this work. The author is grateful to Dr. Basim Almayahi, University of Kufa (basimnajaf@yahoo.com), for assisting throughout conducting the present chapter.

Conflict of interest

The author declares that she has no conflicts of interest.

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Lubna A. Al-Asadi (February 27th 2019). Gamma Background Radiations and Measurements with Applications, Use of Gamma Radiation Techniques in Peaceful Applications, Basim A. Almayah, IntechOpen, DOI: 10.5772/intechopen.83721. Available from:

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