7940018r1d1

PYLON ®

GLOSSARY OF SELECTED PYLON TERMS AND ABBREVIATIONS

MANUAL NUMBER: 7940018

Revision 1 Draft 1

Copyright © 2014 Pylon Electronics Inc. (ALL RIGHTS RESERVED)

® Registered Trademark Canada and U.S.A.

of 15

Document No.: 7940018 Rev 1 Draft 1

DISCLAIMER Pylon Electronics Inc. has attempted to ensure that this manual is complete and accurate. However, Pylon will not be held responsible for any errors and omissions in this manual including consequential damage due to the information contained herein. Please forward all comments and suggestions for improvements on the product or this manual to: Pylon Electronics Inc. 147 Colonnade Road, Ottawa, ON K2E 7L9 CANADA Phone: (613) 226-7920 Fax: (613) 226-8195 Email: [email protected] For technical support, please contact us at the above address. Please visit us on our website at www.pylonelectronics.com. Click on the Products icon.

of 15


TABLE OF CONTENTS

DISCLAIMER .............................................................................................................................................................. 2

1.0 INTRODUCTION............................................................................................................................................... 4

1.1 PURPOSE ............................................................................................................................................................ 4 1.2 SCOPE ................................................................................................................................................................ 4

2.0 GLOSSARY OF SELECTED PYLON TERMS ............................................................................................... 4

of 15


1.0 INTRODUCTION 1.1 Purpose The purpose of this manual is to provide a glossary of selected terms and abbreviations

used by Pylon. 1.2 Scope This manual covers selected terms and abbreviations that are used by Pylon for or radon

and thoron monitors, detectors, accessories, and radioactive sources. These terms and abbreviations are used in many of the manuals produced by Pylon.

2.0 GLOSSARY OF SELECTED PYLON TERMS TERM DEFINITION Active Detector In the context of Pylon instrumentation, a Detector where

the User must actively introduce the gas sample into the detector. Examples of the methodology used include pumping the gas sample into the detector or the use of a vacuum in some detectors to suck the gas sample into the detector.

Background (Bg) The Detector and the Monitor PMT and electronics all generate random signals called noise which are manifested as Counts during measurement. Within the context of radon and thoron measurement, this is called the Background. Normally, there is an attempt to minimise and / or reject this noise. In addition, the value of any remaining noise is taken into account during the calculations.

Becquerel (Bq) A radioactive unit of measure that is equal to 1 disintegration per second.

of 15


TERM DEFINITION Calibration In the context of Pylon radon instrumentation, the

processes that are performed to determine the optimum Operating Point for monitors and the Efficiency and / or Sensitivity of Detectors.

Continuous Sampling One of two types of sampling techniques used to make gas sample measurements for radon or thoron. Counting of pulses generated by the decay of radon or thoron is performed continuously with the results recorded in interval increments. Using the Sensitivity of the detector, the concentration of radon or thoron can be calculated. Average levels can be monitored with this sampling technique.

Count In the context of Pylon instrumentation, the detector converts the Alpha particles produced by the radioactive decay of radon and / or thoron gases into photons of light. These photons of light are converted to electrical pulses in the monitor which are counted over User-defined Intervals. A variety of "Count" terms are described and used for the calculations in the manuals.

of 15


TERM DEFINITION Counts Per Minute (CPM) For analysis, the total number of Counts determined

during an Interval is usually converted into Counts Per Minute. This allows the use of standard formulae to calculate the radon or thoron concentrations. The formula to convert Counts to Counts per Minute (cpm) is:

INTLEN

COUNTSCPM

Where: COUNTS = The total number of counts recorded

in the interval INTLEN = The interval length set by the User

in minutes. A variety of "CPM" terms are described and used for the calculations in the manuals.

Daughter Products (Daughters or Progeny)

Both radon and thoron gas decay into solids known as daughters, daughter products, or progeny. These daughters can be airborne or attached to surfaces. The daughters are radioactive and further decay, releasing Decay Products.

Decay Decay is part of the radioactive process. It involves the emission of Decay Products from the atoms. All radioactive elements are subject to decay.

of 15


TERM DEFINITION Decay Product Each radioactive decay produces a Decay Product. The

Decay Products consist of Alpha particles (He2+), Beta particles (e-), and Gamma energy. Any or all of these Decay Products may be produced during a radioactive decay. In the context of radon and thoron gas decays, only Alpha particles in the energy range of 5 to 10 MeV are of interest.

Detector In the context of Pylon instrumentation, a device that is used to detect the Alpha particles produced by the decay of radon or thoron gas.

Detector Background (DBg)

The Detector Background is the Background counts that are due to the Detector. There are a number of factors that can affect the detector background including but not limited to short-lived radon Daughters, long-lived radon Daughters, thoron Daughters, and other long-lived radio-isotopes. The Detector Background is constantly changing and should be checked on a regular basis by performing a System Background measurement.

Discriminator (DISC) The Discriminator is a control within the Monitor that is used to reject Noise (Background) from the system. Pulses whose energy is below the point set by the Discriminator are rejected by this circuit and not counted. The optimal setting for the set point is determined during calibration.

Disintegration A Disintegration is the emission of a Decay Product as part of the radioactive Decay process. The rate of Decay is determined by measuring the rate of Disintegration (usually in dpm).

of 15


TERM DEFINITION Disintegrations Per

Minute (DPM) Disintegrations Per Minute is a rate of radioactive decay.

Drift Aging and temperature changes cause electrical components to change. This affects parameters such as the Operating Point. The change in values of the parameters over time is known as drift.

Efficiency (E) The mathematical relationship between the number of Counts per unit of time and the number of Disintegrations per unit of time. The following formula is normally used:

DPM

CPME

Electronic Background

(EBg) The Electronic Background is the Background counts that are due to the PMT and the electronics in the Monitor. This is normally determined during the annual operating point determination. The Electronic Background changes very slowly over the course of years. Thus, over the course of a year, it can be considered to be a constant.

Equilibrium In the context of Radon measurements, Equilibrium is reached when the Radon and the Radon Daughter Products are in balance with each other. For Grab Sample measurements, the sample is considered to be at equilibrium 3.5 hours after the sample has been obtained.

Filter A component that is made of material that is designed to trap suspended matter (such as dust particles) from the fluid (e.g., air, water, etc.) passing through it.

Flow Meter A fluid flow indicating and measuring device such as a rotameter. Within the context of radon and thoron measurement, this is normally a gas sample flow measuring device.

of 15


TERM DEFINITION Flow Rate The rate of flow of a fluid. In the case of radon and thoron

measurements, this is the rate of flow of the gas sample. Examples of units of measure include litres per minute (l/min) and meters cubed / minute (m3/min).

Grab Sampling One of two types of sampling techniques used to make gas sample measurements for radon or thoron. The sample is obtained via pumping or vacuum methods (grabbed) and is normally allowed to sit undisturbed until it reaches Equilibrium. Counting of pulses generated by the decay of radon or thoron is then performed with the results recorded in interval increments. Using the Efficiency of the detector, the volume of the detector, the time between the sample collection and the counting, and other factors, the concentration of radon or thoron can be calculated. This sampling technique provides the instantaneous radon or thoron gas concentration at a specific instant in time.

High Voltage (HV) The High Voltage is a control within the Monitor that sets operating voltage of the PMT. The gain of the PMT is related to its operating voltage. i.e., The degree to which the light pulses are amplified by the PMT. The normal range for this voltage is between 600 and 1100 VDC. Higher settings will result in more of the pulses being amplified and counted. However the Background will also increase. The optimal setting for the High Voltage is determined as part of calibration.

of 15


TERM DEFINITION Interval An Interval is the name given to the period of time

determined by the User and programmed into the Monitor for which the Monitor will count the radioactive decay pulses received from the PMT. At the end of the Interval, the Monitor will store the total number of pulses for the interval and start counting from 0 for the next interval. Intervals are automatically numbered by Pylon Monitors. For analysis, the counts per interval usually need to be converted into CPM.

Kusnetz A Grab Sample measurement procedure and calculations for determining Working Levels. See Inkret, W.C., and Borak, T., "Verification of the Generalized Kusnetz Method for Measuring Potential Energy from Rn Daughters", Health Physics 4X, 261 (1985).

Light Pipe A transparent material which transmits light between a Scintillator and a PMT.

Light Pulse A photon or Light Pulse is generated whenever the scintillator in a scintillation type Detector is impacted by a Decay Product. The light pulses pass through a light pipe to the PMT where they are amplified for counting by the Monitor.

Light Shield A material which is used to shield the Scintillator in a Detector from light.

Method In the context of Pylon instrumentation, a defined means to make measurements using either Continuous Sampling or Grab Sampling techniques. Most Methods have User defined parameters.

of 15


TERM DEFINITION Monitor In the context of Pylon instrumentation, a device that is

used in conjunction with a Detector to convert the light pulses generated by the Detector to electrical pulses, amplify and discriminate the electrical pulses, and count the pulses. More advanced monitors include other features such as User-programmable automated methods, calculations, and the measurement of other parameters including but not limited to temperature and relative humidity.

NIST National Institute of Standards and Technology. NIST is the central laboratory for measurement standards and scientific data for the United States of America.

Noise See Background.

NRC National Research Council of Canada. NRC is the central laboratory for measurement standards and scientific data for Canada.

Operating Point The Operating Point is the combination of HV and Disc settings in the Monitor which results in the greatest number of pulses being counted with the minimum amount of background. It is determined during calibration.

Passive Detector In the context of Pylon instrumentation, a Detector where the gas sample passively diffuses into the Detector.

Photomultiplier Tube (PMT)

A cold cathode electron tube for detecting light pulses from a scintillator, converting them into electronic pulses and amplifying the electronic pulses for counting by the Monitor electronics. The degree of amplitude (and therefore the number of pulses counted by the Monitor) is determined by the High Voltage setting.

of 15


TERM DEFINITION PicoCurie (pCi) A radioactive unit of measure that is equal to 10-12 Curie

or 2.22 dpm.

Plateau For certain accessories, Counts made by the Monitor with different HV settings will normally yield a flatter region when plotted against the HV settings for a particular Disc setting. The flatter region of the graph is called a plateau.

QUASI Method A Method that is provided with some of Pylon's monitors. This Method provides for automated multiple Grab Sampling. The User programs the Method for the usual parameters of interval length and the number of intervals. In addition, the User programs the internal pump start and stop intervals as well as the number of loops. Each loop will provide a grab sample measurement. Although Counts are obtained for each interval, only the Counts in selected intervals are used for the manual calculations and data analysis.

Radioactivity Radioactivity is the spontaneous transformation of a nuclide into one or more different nuclides, accompanied by either decay or fission. Radioactivity can be measured by measuring the rate of decay.

Radon A colourless, odourless and chemically inert radioactive gas which occurs in various concentrations almost everywhere. It is about halfway along a chain of radioactive decay which starts with uranium. Radon decays into radon Daughters and gives off Alpha Decay Products.

of 15


TERM DEFINITION Radon Decay Chain As radioactive elements decay, they follow a specific path

of nuclides. The Radon Decay Chain is as follows: 222 Rn 218 Po 214 Pb 214 Bi 214 Po 210 Pb (RaA) (RaB) (RaC) (RaD)

Run In the context of Pylon instrumentation, a Run is a single complete measurement consisting of 1 or more Intervals of measurement. It starts when the monitor starts counting and ends when the monitor automatically stops or is stopped by the User depending on the programming. The data from each run is stored in a file and may be accessed to perform additional data manipulation and analysis.

Scintillator A material that produces light pulses when impacted by a Decay Product. ZnS(Ag) is specific to alpha radiation and is used in a number of the Pylon detectors.

Sensitivity This is a conversion factor that is used to convert the Counts into radioactive concentration units of measure such as Bq/m3 and pCi/l. The Sensitivity is determined during the Calibration process of the Detector. Concentration calculations using the Sensitivity may be automated in the monitor or used for manual or spreadsheet calculations of radon concentration.

Standard Continuous Method

A Method that is provided with some of Pylon's monitors. This Method provides for Continuous Sampling measurements. The User programs the Method for the parameters of interval length and the number of intervals. In this method, the monitor measures continuously until the programmed number of intervals is reached. Average levels can be monitored with this method.

of 15


TERM DEFINITION Standard Grab Method A Method that is provided with some of Pylon's monitors.

This Method provides for Grab Sampling measurements. The User programs the Method for the parameters of interval length and the number of intervals. The measurement is normally started after the gas sample has reached equilibrium. Point in time radon concentration levels can be determined with this method.

System Background (SBg)

The System Background is the total Background of the measurement system which includes the Monitor and the Detector. It is the sum of the Electronic Background and the Detector Background. The System Background value is the value that is used in all of the calculations as it includes all of the background counts from all sources. The System Background is easy to determine by performing the System Background measurement which is described in the manual.

Thoron A colourless, odourless and chemically inert radioactive gas which occurs naturally. It is about halfway along a chain of radioactive decay which starts with thorium. It decays into thoron daughters and gives off Alpha Decay Products.

Traceability Property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.

of 15


TERM DEFINITION Tsivoglou-Thomas A Grab Sample measurement procedure and calculations

for determining Working Levels and Daughter Product concentrations. For more information see Thomas, J.W., "Measurement of Radon Daughters in Air", Health Physics 23, 783-789, 1972.

VDC Direct current volts.

Working Level (WL) A unit of measure for radon Daughter Products. One WL is any combination of RaA, RaB, RaC, and RaC' in one litre of air that results in the ultimate total emission of 1.3 x 105 MeV of alpha energy.

Working Level Grab Method (Radon)

A Method that is provided with some of Pylon's monitors. This Method provides for radon Grab Sampling measurements to obtain the Working Level. The Method provides for fixed parameters such as interval length and the number of intervals for manually calculating the radon Working Level using both the Kusnetz and Tsivoglou-Thomas calculations. Radon Working Levels are determined with this method.

7940018r1d1

Documents