The document defines key terms related to measuring radon levels, including types of measurement devices, units of radioactivity, and concepts like accuracy, precision, and quality control. It distinguishes between active devices that continuously monitor radon versus passive devices like electret ion chambers. Background levels, calibration, and factors that can impact equilibrium ratios are also explained.
QUALIFICATION OF UV-VISIBLE SPECTROPHOTOMETER, FTIR, DSC, HPLCAnupriyaNR
Analytical method qualification consists of a simplified evaluation of a subset of validation characteristics with a goal to demonstrate that an analytical method is scientifically sound and suitable for its intended use. In contrast to validation, analytical method qualification is performed without predefined acceptability criteria. Qualification may be performed as a prerequisite to method validation, or when an assay for product knowledge has not yet been established as a test for a critical product quality attribute. Qualification of equipment is pre-requisite for validation of the process in which the equipment is being used. Many types of equipment have measuring devices on them. Calibration of measuring devices is a part of qualification. Calibration of measuring devices is important, as the data is often collected through them. If the data collected is not from measuring devices that have been calibrated, the data cannot be relied upon. Thus the whole validation exercise can be questioned.
QUALIFICATION OF UV-VISIBLE SPECTROPHOTOMETER, FTIR, DSC, HPLCAnupriyaNR
Analytical method qualification consists of a simplified evaluation of a subset of validation characteristics with a goal to demonstrate that an analytical method is scientifically sound and suitable for its intended use. In contrast to validation, analytical method qualification is performed without predefined acceptability criteria. Qualification may be performed as a prerequisite to method validation, or when an assay for product knowledge has not yet been established as a test for a critical product quality attribute. Qualification of equipment is pre-requisite for validation of the process in which the equipment is being used. Many types of equipment have measuring devices on them. Calibration of measuring devices is a part of qualification. Calibration of measuring devices is important, as the data is often collected through them. If the data collected is not from measuring devices that have been calibrated, the data cannot be relied upon. Thus the whole validation exercise can be questioned.
ENVIRONMENTALLY CORRECTED RSSI BASED REAL TIME LOCATION DETECTION SYSTEMijcsit
RSSI based localization techniques are effected by environmental factors which cause the RF signalsemitted from transmitter nodes fluctuate in time domain. These variations generate fluctuations on distance calculations and result false object position detection during localization.Smoothing procedures must be applied on distance values either collectively or individually to minimize these fluctuations. In this
study,proposed detection system has two main phases. Firstly, calibration of RSSI values with respect to distances and calculation of environmental coefficient for each ransmitter.Secondly, position estimation of objects by applyingiterative trilateration on smoothed distance values. A smoothing algorithm is employed to minimize the dynamic fluctuations of RF signals received from each reference transmitter node. Distances between the reference nodes and the objects are calculated by deploying environmental
coefficients. Experimental measurements are carried out to measure the sensitivity of the system. Results show that the proposed system can be deployed as a viable position detection system in indoors and outdoors.
6th Training Course on Radiation Protection for Radiation Workers and RCOs of BAEC, Medical Facilities & Industries
Training Institute, AERE, Savar, BAEC
24 - 29 October 2021
This presentation was a plenary talk on environmental forensics delivered at the 2011 Dioxin Conference in Brussels (www.dioxin2011.org). The presentation focused on the topic of environmental forensics investigations and techniques and their application to the field of persistent organic pollutants (POPs).
High-accuracy laser spectrometers for wireless trace-gas sensor networksClinton Smith
The subject of this dissertation is the development of a wireless sensor network composed of instruments which employ both VCSELs and QCLs for accurate, highly sensitive, and reliable long-term monitoring of environmental trace-gases. The dissertation focuses on the development of low-power instruments and calibration methods that ensure the reliability of long-term measurements.
First the field deployment of a low-power, portable, wireless laser spectroscopic sensor node for atmospheric CO2 monitoring is demonstrated. The sensor node shows 0.14 ppmv Hz^-1/2 1 sigma measurement sensitivity of CO2 concentration changes. It was first used to measure top-soil respiration rates in the laboratory and on forest floors in the field.
Then after a long-term field deployment to further assess instrument performance, new design solutions were implemented to improve fringe-limited precision of the nodes to 4-7 ppmv against a 400 ppmv CO2 background, making their performance comparable to higher power consuming commercial trace-gas analyzers. Three optimized nodes were then deployed into mixed landscapes as part of a solar powered CO2 monitoring wireless network. The three node network monitored CO2 in a grassy/woody courtyard, on top of the roof of an engineering building, and next to a road in the Princeton area. These works show that ultra-low powered VCSEL based sensor nodes can be placed in off-the-grid environments for autonomous distributed geographic monitoring of trace-gases in a manner which is impossible with current commercial techniques.
Next, this dissertation covers two techniques that were developed for the real-time calibration of laser-based trace-gas measurements. The first technique used an in-line reference gas cell and employed wavelength modulation spectroscopy (WMS) at higher harmonics to simultaneously probe the sample and reference spectra. The second technique used a revolving in-line reference cell to suppress background and other non-spectroscopic signals. These techniques were designed for eventual inclusion as a real-time calibration source for field deployable trace-gas sensors and wireless sensor networks.
Finally, this dissertation demonstrates the use of the CW injection current into a VCSEL in an external cavity configuration to tune the cavity emission's self-oscillation frequency and show through simulation and experiment that the tuning is dependent on VCSEL birefringence change.
Dissertation PDF at www.clintonjsmith.com
It will guide to about the air sampling process which is essential step before you proceed for any type of research regarding air pollution, pollutants and health effects.
Laser-Based Standoff Methane Sensors for Enhancing Coal Miner SafetyClinton Smith
This presentation shows a demonstration of the PSI & Heath Consultants Remote Methane Leak Detector (RMLD) being applied to remote detection of methane within coal mines to supplement existing technology to further enhance coal miner safety.
It is a multi-element analysis technique that will separate a sample into its constituent atoms and ions and excite it to a higher energy level.
Cause them to emit light with a distinct wavelength, which will be analyzed.
Air Quality Sampling and Monitoring: Stack sampling, instrumentation and methods of analysis of SO2, CO etc, legislation for control of air pollution and automobile
pollution
An evaporative light scattering detector (ELSD) is a detector used or analysis of compounds where UV detection might be a restriction and therefore used where compounds do not efficiently absorb UV radiation, such as sugars, antivirals, antibiotics, fatty acids, lipids, oils, phospholipids, polymers, surfactants, terpenoids and triglycerides.ELSDs is related to the charged aerosol detector (CAD) and like the CAD, falls under the category of destructive detectors.
ENVIRONMENTALLY CORRECTED RSSI BASED REAL TIME LOCATION DETECTION SYSTEMijcsit
RSSI based localization techniques are effected by environmental factors which cause the RF signalsemitted from transmitter nodes fluctuate in time domain. These variations generate fluctuations on distance calculations and result false object position detection during localization.Smoothing procedures must be applied on distance values either collectively or individually to minimize these fluctuations. In this
study,proposed detection system has two main phases. Firstly, calibration of RSSI values with respect to distances and calculation of environmental coefficient for each ransmitter.Secondly, position estimation of objects by applyingiterative trilateration on smoothed distance values. A smoothing algorithm is employed to minimize the dynamic fluctuations of RF signals received from each reference transmitter node. Distances between the reference nodes and the objects are calculated by deploying environmental
coefficients. Experimental measurements are carried out to measure the sensitivity of the system. Results show that the proposed system can be deployed as a viable position detection system in indoors and outdoors.
6th Training Course on Radiation Protection for Radiation Workers and RCOs of BAEC, Medical Facilities & Industries
Training Institute, AERE, Savar, BAEC
24 - 29 October 2021
This presentation was a plenary talk on environmental forensics delivered at the 2011 Dioxin Conference in Brussels (www.dioxin2011.org). The presentation focused on the topic of environmental forensics investigations and techniques and their application to the field of persistent organic pollutants (POPs).
High-accuracy laser spectrometers for wireless trace-gas sensor networksClinton Smith
The subject of this dissertation is the development of a wireless sensor network composed of instruments which employ both VCSELs and QCLs for accurate, highly sensitive, and reliable long-term monitoring of environmental trace-gases. The dissertation focuses on the development of low-power instruments and calibration methods that ensure the reliability of long-term measurements.
First the field deployment of a low-power, portable, wireless laser spectroscopic sensor node for atmospheric CO2 monitoring is demonstrated. The sensor node shows 0.14 ppmv Hz^-1/2 1 sigma measurement sensitivity of CO2 concentration changes. It was first used to measure top-soil respiration rates in the laboratory and on forest floors in the field.
Then after a long-term field deployment to further assess instrument performance, new design solutions were implemented to improve fringe-limited precision of the nodes to 4-7 ppmv against a 400 ppmv CO2 background, making their performance comparable to higher power consuming commercial trace-gas analyzers. Three optimized nodes were then deployed into mixed landscapes as part of a solar powered CO2 monitoring wireless network. The three node network monitored CO2 in a grassy/woody courtyard, on top of the roof of an engineering building, and next to a road in the Princeton area. These works show that ultra-low powered VCSEL based sensor nodes can be placed in off-the-grid environments for autonomous distributed geographic monitoring of trace-gases in a manner which is impossible with current commercial techniques.
Next, this dissertation covers two techniques that were developed for the real-time calibration of laser-based trace-gas measurements. The first technique used an in-line reference gas cell and employed wavelength modulation spectroscopy (WMS) at higher harmonics to simultaneously probe the sample and reference spectra. The second technique used a revolving in-line reference cell to suppress background and other non-spectroscopic signals. These techniques were designed for eventual inclusion as a real-time calibration source for field deployable trace-gas sensors and wireless sensor networks.
Finally, this dissertation demonstrates the use of the CW injection current into a VCSEL in an external cavity configuration to tune the cavity emission's self-oscillation frequency and show through simulation and experiment that the tuning is dependent on VCSEL birefringence change.
Dissertation PDF at www.clintonjsmith.com
It will guide to about the air sampling process which is essential step before you proceed for any type of research regarding air pollution, pollutants and health effects.
Laser-Based Standoff Methane Sensors for Enhancing Coal Miner SafetyClinton Smith
This presentation shows a demonstration of the PSI & Heath Consultants Remote Methane Leak Detector (RMLD) being applied to remote detection of methane within coal mines to supplement existing technology to further enhance coal miner safety.
It is a multi-element analysis technique that will separate a sample into its constituent atoms and ions and excite it to a higher energy level.
Cause them to emit light with a distinct wavelength, which will be analyzed.
Air Quality Sampling and Monitoring: Stack sampling, instrumentation and methods of analysis of SO2, CO etc, legislation for control of air pollution and automobile
pollution
An evaporative light scattering detector (ELSD) is a detector used or analysis of compounds where UV detection might be a restriction and therefore used where compounds do not efficiently absorb UV radiation, such as sugars, antivirals, antibiotics, fatty acids, lipids, oils, phospholipids, polymers, surfactants, terpenoids and triglycerides.ELSDs is related to the charged aerosol detector (CAD) and like the CAD, falls under the category of destructive detectors.
Final year project: To Design and Test a low cost Gamma Ray detectorChristopher Mitchell
Smartphone cameras have the ability to be converted into ionising radiation detectors by covering the lens. The lens detects high-energy photons emitted by a variety of gamma radiation sources. The gamma detector is limited by its inability to differentiate between the energies of the radiation fields it is detecting, however the detector can be calibrated to give the estimated dose (μSv/hr). It has the ability to be used as a personal dosimeter. The detector is not very sensitive and is subject to thermal noise. The radiation intensity detected varies from phone to phone. However linearity plots of counts versus dose rate can be obtained regardless of noise or sensitivity values. The measurements of the detector are sensitive to the position and angle of the source. The following parameters were tested as part of this investigation: Calibration of device with sources, thermal noise, distance of source, shielding effects, resolving time of detector, variance of count rate with angle and absolute efficiency comparison to semiconductor detectors. The detector follows the radiation theory tested such as the inverse square law and the law of absorption. The Smartphone detector is a low cost dose meter that can provide estimated dose readings of radiation sources, although it is not as efficient as other semiconductor detectors, this low cost detector is much cheaper than its professional detector counterparts and there are more smartphones available than detectors. So the smartphone at times may be the best gamma detector available.
RADIATIONS UNITS AND IT’S MEASUREMENT BY SAGAR CHAULAGAIN.pptxSagar Chaulagain
This presentation includes introduction to radiation, the basic knowledge of various radiations units, types of detectors which are being used to measure that radiation units and this presentation includes personal monitoring devices likes film badge dosimeter, thermoluminescent dosimeter (TLD), Optically stimulated luminescent dosimeter (OSL) and pocket dosimeters. in these slides very simple english language is used and the arrangement of the topics in the presentation is well managed . these presentation is usually for the radiographers and a radiotechnologist for which the basic knowledge of radiation units and it's measurements is crucial.
Units of Radiation Measurements, Quality Specification, Half-Value Thickness,...Dr. Dheeraj Kumar
Radiation measurements are essential for quantifying radiation exposure, absorbed dose, and activity, providing crucial information for medical physics and radiology.
Liquid Sensing: Visible light absorption spectroscopy and colorimetry are two fundamental tools used in chemical analysis. Most of these light-based systems use photodiodes as the light sensor, and require similar high input impedance signal chains. This session examines the different components of a photodiode amplifier signal chain, including a programmable gain transimpedance amplifier, a hardware lock-in amplifier, and a Σ-Δ ADC that can measure a sample and reference channel to greatly reduce any measurement error due to variations in intensity of the light source.
Gas Sensing: Many industrial processes involve toxic compounds, and it is important to know when dangerous concentrations exist. Electrochemical sensors offer several advantages for instruments that detect or measure the concentration of toxic gases. This session will describe a portable toxic gas detector using an electrochemical sensor. The system presented here includes a potentiostat circuit to drive the sensor, as well as a transimpedance amplifier to take the very small output current from the sensor and translate it to a voltage that can take advantage of the full-scale input of an ADC.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Welocme to ViralQR, your best QR code generator.ViralQR
Welcome to ViralQR, your best QR code generator available on the market!
At ViralQR, we design static and dynamic QR codes. Our mission is to make business operations easier and customer engagement more powerful through the use of QR technology. Be it a small-scale business or a huge enterprise, our easy-to-use platform provides multiple choices that can be tailored according to your company's branding and marketing strategies.
Our Vision
We are here to make the process of creating QR codes easy and smooth, thus enhancing customer interaction and making business more fluid. We very strongly believe in the ability of QR codes to change the world for businesses in their interaction with customers and are set on making that technology accessible and usable far and wide.
Our Achievements
Ever since its inception, we have successfully served many clients by offering QR codes in their marketing, service delivery, and collection of feedback across various industries. Our platform has been recognized for its ease of use and amazing features, which helped a business to make QR codes.
Our Services
At ViralQR, here is a comprehensive suite of services that caters to your very needs:
Static QR Codes: Create free static QR codes. These QR codes are able to store significant information such as URLs, vCards, plain text, emails and SMS, Wi-Fi credentials, and Bitcoin addresses.
Dynamic QR codes: These also have all the advanced features but are subscription-based. They can directly link to PDF files, images, micro-landing pages, social accounts, review forms, business pages, and applications. In addition, they can be branded with CTAs, frames, patterns, colors, and logos to enhance your branding.
Pricing and Packages
Additionally, there is a 14-day free offer to ViralQR, which is an exceptional opportunity for new users to take a feel of this platform. One can easily subscribe from there and experience the full dynamic of using QR codes. The subscription plans are not only meant for business; they are priced very flexibly so that literally every business could afford to benefit from our service.
Why choose us?
ViralQR will provide services for marketing, advertising, catering, retail, and the like. The QR codes can be posted on fliers, packaging, merchandise, and banners, as well as to substitute for cash and cards in a restaurant or coffee shop. With QR codes integrated into your business, improve customer engagement and streamline operations.
Comprehensive Analytics
Subscribers of ViralQR receive detailed analytics and tracking tools in light of having a view of the core values of QR code performance. Our analytics dashboard shows aggregate views and unique views, as well as detailed information about each impression, including time, device, browser, and estimated location by city and country.
So, thank you for choosing ViralQR; we have an offer of nothing but the best in terms of QR code services to meet business diversity!
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
The Art of the Pitch: WordPress Relationships and Sales
Radon glossary
1. Radon Glossary of Terms
Accuracy: The degree of agreement of a measurement (X) with an accepted reference or
true value (T); usually expressed as the difference between the two values (X – T), or the
difference as a percentage of the reference or true value (100[X – T]/T), and sometimes
expressed as a ratio (X/T).
Active radon/radon decay product measurement device: A radon or radon decay
product measurement system which uses a sampling device, detector, and measurement
system integrated as a complete unit or as separate, but portable, components. Active
devices include continuous radon monitors, continuous working level monitors, and grab
radon gas and grab working level measurement systems, but does not include devices
such as electret ion chamber devices, activated carbon or other adsorbent systems, or
alpha track devices.
Alpha particle: Two neutrons and two protons bound as a single particle that is emitted
from the nucleus of certain radioactive isotopes in the process of decay.
Background count rate: The counting rate obtained on a given instrument with a
background counting sample. Typical reference background counting samples are:
Empty planchet: for G-M detectors, internal proportional counters, low background
beta counters, alpha spectrometers.
Scintillation vial containing scintillant and sample known to contain no
radioactivity: for liquid scintillation counters.
Container filled with distilled water: for gamma spectrometers.
Background measurements: Measurements made with either active instruments
exposed to a radon-free gas, such as aged air or nitrogen, or for passive detectors by
analyzing unexposed detectors. Results are subtracted from the actual field measurements
before calculating the reported concentration. Background levels may be due to electronic
noise of the analysis system, leakage of radon into the detector, detector response to
gamma radiation, or other causes.
Background radiation: Radiation arising from radioactive material other than that under
consideration. Background radiation due to cosmic rays and natural radioactivity is
always present; background radiation may also be due to the presence of radioactive
substances in building materials.
2. Radon Glossary of Terms
Bias: A systematic (consistent) error in test results. Bias can exist between test results
and the true value (absolute bias, or lack of accuracy), or between results from different
sources (relative bias). For example, if different laboratories analyze a homogeneous and
stable blind sample, the relative biases among the laboratories would be measured by the
differences existing among the results from the different laboratories. However, if the
true value of the blind sample were known, the absolute bias or lack of accuracy from the
true value would be known for each laboratory. See Systematic error.
Blank sample: A control sample in which the detector is unexposed and submitted for
analysis. Often used to determine detector background values.
Blind spikes: Detectors exposed to known radon or decay product concentrations and
submitted for analysis without being labeled as such. Used to evaluate the accuracy of the
measurement.
Calibrate: To determine the response or reading of an instrument relative to a series of
known values over the range of the instrument; results are used to develop correction or
calibration factors.
Check source: A radioactive source, not necessarily calibrated, which is used to confirm
the continuing satisfactory operation of an instrument.
Coefficient of variation (COV), relative standard deviation (RSD): A measure of
precision, calculated as the standard deviation (s or s) of a set of values divided by the
average (Xave or µ), and usually multiplied by 100 to be expressed as a percentage.
COV = RSD = / x 100 for a sample,
COV' = RSD' = / x 100 for a population
See Relative percent difference.
curie (Ci): A standard measurement for radioactivity, specifically the rate of decay for a
gram of radium – 37 billion decays per second. A unit of radioactivity equal to 3.7 x 1010
disintegrations per second.
3. Radon Glossary of Terms
Duplicate measurements: Two measurements made concurrently and in the same
location, or side-by-side. Used to evaluate the precision of the measurement method.
Electron: An elementary constituent of an atom that orbits the nucleus and has a negative
charge. Beta decay is radioactive decay in which an electron is emitted from a nucleus.
Electron volt (eV): One eV is equivalent to the energy gained by an electron in passing
through a potential difference of one volt. One unit of energy = 1.6 x 10-12 ergs = 1.6 x
10-19 joules; 1 MeV = 106 eV.
Equilibrium, radioactive: A state in which the formation of atoms by decay of a parent
radioactive isotope is equal to its rate of disintegration by radioactive decay.
Equilibrium ratio, radioactive: The total concentration of radon decay products (RDPs)
present divided by the concentration that would exist if the RDPs were in radioactive
equilibrium with the radon gas concentration which is present. At equilibrium (i.e., at an
equilibrium ratio of 1.0), 1 WL of RDPs would be present when the radon concentration
was 100 pCi/L. The ratio is never 1.0 in a house. Due to ventilation and plate-out, the
RDPs never reach equilibrium in a house environment. A commonly assumed
equilibrium ratio is 0.5 (i.e., the progeny are halfway toward equilibrium), in which case
1 WL corresponds to 200 pCi/L. However, equilibrium ratios vary with time and
location, and ratios of 0.3 to 0.7 are commonly observed. Large buildings, including
schools, often contain equilibrium ratios less than 0.5.
Exposure time: The length of time a specific mail-in device must be in contact with
radon or radon decay products to get an accurate radon measurement. Also called
exposure period, exposure parameters, or duration of exposure.
Gamma radiation: Short-wavelength electromagnetic radiation of nuclear origin, with
energies between 10 keV to 9 MeV.
Integrating device: A device that measures a single average concentration value over a
period of time. Also called a time integrating device.
4. Radon Glossary of Terms
Ion: An electrically charged atom in which the number of electrons does not equal the
number of protons.
Ionization: The process whereby a neutral atom or molecule becomes negatively or
positively charged by acquiring or losing an electron.
Ionizing radiation: Any type of radiation capable of producing ionization in materials it
contacts; includes high-energy charged particles such as alpha and beta rays, and non-
particulate radiation such as gamma rays and X-rays. In contrast to wave radiation (e.g.,
visible light and radio waves) in which waves do not ionize adjacent atoms as they move.
Lower limit of detection (LLD): The smallest amount of sample activity which will
yield a net count for which there is confidence at a predetermined level that activity is
present. For a five percent probability of concluding falsely that activity is present, the
LLD is approximately equal to 4.65 times the standard deviation of the background
counts (assuming large numbers of counts where Gaussian statistics can be used [ANSI
1989, Pasternack and Harley 1971, U.S. DOE 1990]).
Passive radon/radon decay product measurement device: A radon or radon decay
product measurement system in which the sampling device, detector, and measurement
system do not function as a complete, integrated unit. Passive devices include electret ion
chamber devices, activated carbon or other adsorbent systems, or alpha track devices, but
does not include continuous radon/radon decay product monitors, or grab radon/radon
decay product measurement systems.
picocurie (pCi): One pCi is one trillionth of a curie, 0.037 disintegrations per second, or
2.22 disintegrations per minute.
picocurie per liter (pCi/L): A unit of radioactivity corresponding to one decay every 27
seconds in a volume of one liter, or 0.037 decays per second in every liter of air.
Pooled estimate of variance: An estimate of precision derived from different sets of
duplicates, calculated as follows:
S2dp = s2d1 (n1 - 1) + S2ds (n2 - 1)/(n1 - 1) + (n2 - 1)
5. Radon Glossary of Terms
where:
S2dp = pooled variance;
S2d1 = variance observed with the first group of detectors or equipment;
S2d2 = variance observed with the second group of detectors or equipment;
n1 = sample size of the first group of detectors or equipment; and
n2 = sample size of the second group of detectors or equipment.
Precision: A measure of mutual agreement among individual measurements of the same
property, usually under prescribed and similar conditions. Most desirably expressed in
terms of the standard deviation, but can be expressed in terms of the variance, pooled
estimate of variance, range, relative percent difference, or other statistic.
Quality assurance: A complete program designed to produce results which are valid,
scientifically defensible, and of known precision, bias, and accuracy. Includes planning,
documentation, and quality control activities.
Quality control: The system of activities to ensure a quality product, including
measurements made to ensure and monitor data quality. Includes calibrations, duplicate,
blank, and spiked measurements, interlaboratory comparisons, and audits.
Radon (Rn): A colorless, odorless, naturally occurring, radioactive, inert, gaseous
element formed by radioactive decay of radium (Ra) atoms. The atomic number is 86.
Although other isotopes of radon occur in nature, radon in indoor air is almost
exclusively Rn-222.
Radon chamber: An airtight enclosure in which operators can induce and control
different levels of radon gas and radon decay products. Volume is such that samples can
be taken without affecting the levels of either radon or its decay products within the
chamber.
Random error: Variations of repeated measurements that are random in nature and not
predictable individually. The causes of random error are assumed to be indeterminate or
non-assignable. The distribution of random errors is assumed generally to be normal
(Gaussian).
6. Radon Glossary of Terms
Range: The difference between the maximum and minimum values of a set of values.
When the number of values is small (i.e., eight or less), the range is a relatively sensitive
(efficient) measure of variability. As the number of values increases above eight, the
efficiency of the range (as an estimator of the variability) decreases rapidly. The range, or
difference between two paired values, is of particular importance in air pollution
measurement, since in many situations duplicate measurements are performed as part of
the quality assurance program.
Relative percent difference (RPD): A measure of precision, calculated by:
Rd% = [X1 - X2}/Xave x 100
where:
X1 = concentration observed with the first detector or equipment;
X2 = concentration observed with the second detector, equipment, or absolute value; and
Xave = average concentration = ((X1 + X2) / 2)
The relative percent difference (RPD) and coefficient of variation (COV) provide a
measure of precision, but they are not equal. Below are example duplicate radon results
and the corresponding values of relative percent difference and coefficient of variation: