ANSI IEEE N42 31-2003 Measurement Procedures for Resolution and Efficiency of Wide-Bandgap Semiconductor Detectors of Ionizing Radiation.pdf

1、ANSI N42.31-2003IEEE StandardsN42.31American National Standard forMeasurement Procedures forResolution and Efficiency ofWide-Bandgap SemiconductorDetectors of Ionizing RadiationPublished by The Institute of Electrical and Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USA20 Augus

2、t 2003Accredited by the American National Standards InstituteSponsored by theNational Committee on Radiation Instrumentation, N42IEEE StandardsPrint: SH95166PDF: SS95166ANSI N42.31-2003American National Standard for Measurement Procedures for Resolution and Efficiency of Wide-Bandgap Semiconductor D

3、etectors of Ionizing RadiationSponsorNational Committee on Radiation Instrumentation, N42Accredited by the American National Standards InstituteSecretariatThe Institute of Electrical and Electronics Engineers, Inc.Approved 20 February 2003American National Standards InstituteAbstract: Standard measu

4、rement and test procedures are established for wide-bandgapsemiconductor detectors such as cadmium telluride (CdTe), cadmium-zinc-telluride (CdZnTe), andmercuric iodide (HgI2) that can be used at room temperature for the detection and quantitativecharacterization of gamma-rays, X-rays, and charged p

5、articles. Standard terminology anddescriptions of the principal features of the detectors are included. Included in this standard is anannex on interfering electromagnetic noise, which is a factor in such measurements.Keywords: cadmium telluride, cadmium zinc telluride, CdTe, charged particle, CZT,

6、electron-holepair, gamma rays, HgI, ionizing radiation, ion pair, MCA, mercuric iodide, multichannel analyzer,semiconductor detector, X-rayThe Institute of Electrical and Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USACopyright 2003 by the Institute of Electrical and Electroni

7、c Engineers, Inc.All rights reserved. Published 20 August 2003. Printed in the United States of America.Print: ISBN 0-7381-3798-7 SH95166PDF: ISBN 0-7381-3799-5 SS95166No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written

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17、btained through the Copyright Clearance Center.iv Copyright 2003 IEEE. All rights reserved.Introduction(This introduction is not part of ANSI N42.31-2003, American National Standard for Measurement Procedures forResolution and Efficiency of Wide-Bandgap Semiconductor Detectors of Ionizing Radiation.

18、)This standard is the responsibility of the Accredited American Standards Committee on Radiation Instrumentation, N42.The standard was approved on N42 letter ballot of 10 July 2002.ParticipantsAt the time it approved this standard, the Accredited Standards Committee on Radiation Instrumentation, N42

19、, had thefollowing members:Louis Costrell, ChairMichael P. Unterweger, Vice ChairSue Vogel, Administrative SecretaryOrganization Represented Name of RepresentativeAmerican Conference of Governmental Industrial Hygienists. Jesse LiebermanBattelle NW Laboratories Joseph C. McDonaldBicron . Joseph G. B

20、ellianChew, M.H. Jack M. SelbyCommerce Dept, U.S., NIST .Louis Costrell.Michael P. Unterweger (Alt.)Eberline Instruments .Mitchell TruittEnergy Dept, U.S., OHER/PCSRD Natesch VaramaEntergy-ANO .Ron SchwartzFemo-TECH Inc. . Richard StraubGamma-Metrics . Ernesto A. CorteGeneral Activities Inc. Karl Re

21、initzHealth Physics Society Joseph StencelInstitute of Electrical gamma rays, X-rays, and chargedparticles are covered. The measurement procedures described herein apply primarily to detector elementshaving planar, hemispherical, or other geometries in which charge carriers of both polarities contri

22、bute tothe output signal. When the devices are an integral part of a system, it may not be possible for a user to maketests on the detector alone. In this instance, tests on the detector element must be established by mutualagreement between the manufacturer and the user.1.2 PurposeThe purpose of th

23、is standard is to establish terminology and test procedures that have the same meaning toboth manufacturers and users. Not all tests described in this standard are mandatory, but those used tospecify performance shall be made in accordance with the procedures described herein. (Use of the word“shall

24、” indicates a mandatory requirement, “must” a physical one, and “should” means “recommended.”)1.3 AbbreviationsAbbreviations, defined in 3.3, are used liberally throughout this document.ANSIStd N42.31-2003 AMERICAN NATIONAL STANDARD FOR MEASUREMENT PROCEDURES FOR RESOLUTION2 Copyright 2003 IEEE. All

25、 rights reserved.2. ReferencesStandards referred to herein are listed below. The details of the test instruments and the test proceduresdescribed in two of the standardsIEEE Std 301-1988 and IEEE Std 325-1996are closely related tothose described in this document and are recommended as adjuncts to it

26、.DOE Report DOE/ER-0457T (May 1990), Standard NIM Instrumentation System.1IEEE Std 194-1977, IEEE Standard Pulse Terms and Definitions.2,3,4IEEE Std 300-1988 (Reaff 1993), IEEE Standard Test Procedures for Semiconductor Charged-ParticleDetectors.IEEE Std 301-1988, IEEE Standard Test Procedures for A

27、mplifiers and Preamplifiers used with Detectorsof Ionizing Radiation.IEEE Std 325-1996, IEEE Standard Test Procedures for Germanium Gamma-Ray Detectors.IEEE Std 759-1984, IEEE Standard Test Procedures for Semiconductor X-Ray Energy Spectrometers.IEEE Std 1160-1993, IEEE Standard Test Procedures for

28、High-Purity Germanium Crystals for RadiationDetectors.3. Definitions, symbols, and abbreviations3.1 DefinitionsSpecialized terms used in this standard plus some others that are relevant appear in this subclause. Most ofthe technical terms within the definitions are themselves defined here but, with

29、a few exceptions, are notcross-referenced. Terms used infrequently in the document are defined where they appear; they may or maynot be defined in this subclause.3.1.1 active region: A region of a detector in which charge created by ionizing radiation contributessignificantly to the output signal.3.

30、1.2 amplifier: An electronic instrument for increasing the amplitude of a signal.3.1.3 amplifier shaping time: A nonspecific indication of the shaped-pulse width issuing from a pulseamplifier.3.1.4 amplifier time constant: A misnomer for the width of the shaped pulse issuing from a pulse amplifier.S

31、ee: shaping-time index (t0.5).1Available from Louis Costrell, NIM Committee Chairman, or Michael Unterweger, NIM Committee Vice-chairman, both at NationalInstitute of Standards and Technology, Radiation Physics Division or from the National Technical Information Service, U.S. Dept. ofCommerce, Sprin

32、gfield, VA 22161.2The IEEE standards or products referred to in Clause 2 are trademarks owned by the Institute of Electrical and Electronics Engineers,Incorporated.3IEEE Std 194-1977 has been withdrawn; however, copies can be obtained from Global Engineering, 15 Inverness Way East, Engle-wood, CO 80

33、112-5704, USA, tel. (303) 792-2181 (http:/ publications are available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway,NJ 08855-1331, USA (http:/standards.ieee.org/).ANSIAND EFFICIENCY OF WIDE-BANDGAP SEMICONDUCTOR DETECTORS Std N42.31-2003Copyrigh

34、t 2003 IEEE. All rights reserved. 33.1.5 analog-to-digital converter (ADC): An instrument that digitally encodes electrical pulses accordingto their amplitudes. An ADC is usually part of a multichannel analyzer (MCA).3.1.6 area (of all or part of a spectral line): The counts accumulated within a sel

35、ected number of channelsin a spectral line.3.1.7 background: Unwanted counts that appear in a spectrum due to ambient radiation, to a test sourcecontaining emitters other than the desired ones, or to spectral distortions caused by pulse pile-up.3.1.8 background (ambient): The spectrum of ionizing ra

36、diation observed when a test source is replaced bya blank which is identical to the test source except for the absence of radioactivity.3.1.9 ballistic deficit (BD): The loss in signal amplitude that occurs when the charge collection time in adetector is a significant fraction of the amplifiers diff

37、erentiating time constant.3.1.10 bandgap: The energy difference between the bottom of the conduction band and the top of thevalence band.3.1.11 baseline (of an electrical pulse): The average of the levels from which a pulse departs and to whichit returns in the absence of an overlapping pulse (IEEE

38、Std 194-1977).3.1.12 baseline restorer (BLR): A circuit that rapidly restores the baseline following an amplifiers outputpulse (or train of pulses) to the level that existed before the pulse.3.1.13 bias, detector: The voltage applied to a detector to produce the electric field that sweeps out thesig

39、nal charge. 3.1.14 bias resistor: The resistor through which the bias voltage is applied to a detector.3.1.15 bipolar pulse: A signal pulse having two lobes, one above and the other below the baseline. Whenproduced by a linear filter network, the two lobes have the same area but not necessarily the

40、same peakamplitude.3.1.16 capacitance, detector: The electrical capacitance measured between terminals of the detector underspecified conditions of bias and frequency and with the amplitude of the signal used for the capacitancedetermination being small compared with the bandgap of the semiconductor

41、 comprising the detector.3.1.17 carrier: See: charge carrier.3.1.18 center line: See: peak center line.3.1.19 channel: Refers to the channels in a multichannel analyzer.3.1.20 charge carrier: A mobile electron or hole.3.1.21 charge collection time: The time required for a charge produced by an ioniz

42、ing event to be collectedat the terminal of a detector under the influence of the detector bias voltage.3.1.22 charge-sensitive preamplifier: An amplifier, preceding the main amplifier, in which the outputamplitude is proportional to the charge injected at its input and virtually independent of dete

43、ctor capacitance(IEEE Std 301-1988).3.1.23 contact: A conducting area applied to the surface of a detector to make electrical contact with it.ANSIStd N42.31-2003 AMERICAN NATIONAL STANDARD FOR MEASUREMENT PROCEDURES FOR RESOLUTION4 Copyright 2003 IEEE. All rights reserved.3.1.24 CR differentiator: A

44、 high-pass electrical filter section comprising a capacitor in series with thesignal path followed by a resistor across the path.3.1.25 (CR)m-(RC)n shaping: In an amplifier, the pulse shape produced by m CR high-pass filter sections(differentiators) in conjunction with n RC low-pass filter sections

45、(integrators), all with the same timeconstant. If the input signal is a step function and no other high-pass sections are in the signal path, the pulseshape is unipolar if m = 1, bipolar if m = 2. For unipolar pulses, the waveform is described by Ktnet/, whereK is a constant, t is time, and is the t

46、ime constant of the differentiator.3.1.26 dead layer: In a semiconductor detector, a layer (frequently associated with a contact region) inwhich no significant part of the energy lost by photons or particles can contribute to the resulting signal.3.1.27 dead time: The interval during which the secon

47、d of two events is lost or is recorded with an error inits amplitude.3.1.28 decay time constant: In the absence of a low-pass network preceding the point of observation, thetime for a single-exponential waveform to decay to the fraction 1/e of its original amplitude.3.1.29 depletion region: A region

48、 in which the mobile charge-carrier density is insufficient to neutralize thenet fixed charge density of donors and acceptors. In a diode-type semiconductor radiation detector, thedepletion region is the active (sensitive) region.3.1.30 depletion voltage: The voltage at which a junction detector bec

49、omes fully depleted.3.1.31 detector element: The semiconductor crystal including its contacts.3.1.32 detector, semiconductor radiation: A semiconductor device in which the production and motion ofexcess free carriers is used for the detection and measurement of incident particles or photons.3.1.33 differentiator: A high-pass filter network (usually a CR section) in which the waveform of the outputsignal approximates the mathematical derivative of the input waveform.3.1.34 discriminator: A circuit having a threshold below which signals applied to