430:
476:
20:
164:
204:. This group of primary electrons is electrostatically accelerated and focused by an electrical potential so that they strike the first dynode of the tube. The impact of a single electron on the dynode releases a number of secondary electrons which are in turn accelerated to strike the second dynode. Each subsequent dynode impact releases further electrons, and so there is a current amplifying effect at each dynode stage. Each stage is at a higher potential than the previous to provide the accelerating field.
438:
176:
369:
219:
The scintillator must be shielded from all ambient light so that external photons do not swamp the ionization events caused by incident radiation. To achieve this a thin opaque foil, such as aluminized mylar, is often used, though it must have a low enough mass to minimize undue attenuation of the
199:
The chemistry of atomic de-excitation in the scintillator produces a multitude of low-energy photons, typically near the blue end of the visible spectrum. The quantity is proportional to the energy deposited by the ionizing particle. These can be directed to the photocathode of a photomultiplier
448:
monitors, for area or personal surveys require a large detection area to ensure efficient and rapid coverage of monitored surfaces. For this a thin scintillator with a large area window and an integrated photomultiplier tube is ideally suited. They find wide application in the field of radioactive
391:
Several products have been introduced in the market utilising scintillation counters for detection of potentially dangerous gamma-emitting materials during transport. These include scintillation counters designed for freight terminals, border security, ports, weigh bridge applications, scrap metal
452:
A scintillator such as zinc sulphide is used for alpha particle detection, whilst plastic scintillators are used for beta detection. The resultant scintillation energies can be discriminated so that alpha and beta counts can be measured separately with the same detector, This technique is used in
135:(a simple microscope) to observe light flashes in the scintillator. The first commercial liquid scintillation counter was made by Lyle E. Packard and sold to Argonne Cancer Research Hospital at the University of Chicago in 1953. The production model was designed especially for
449:
contamination monitoring of personnel and the environment. Detectors are designed to have one or two scintillation materials, depending on the application. "Single phosphor" detectors are used for either alpha or beta, and "Dual phosphor" detectors are used to detect both.
207:
The resultant output signal at the anode is a measurable pulse for each group of photons from an original ionizing event in the scintillator that arrived at the photocathode and carries information about the energy of the original incident radiation. When it is fed to a
183:
When an ionizing particle passes into the scintillator material, atoms are excited along a track. For charged particles the track is the path of the particle itself. For gamma rays (uncharged), their energy is converted to an energetic electron via either the
514:
vs number of the flashes, which approximates the energy spectrum of the incident radiation, with some additional artifacts. A monochromatic gamma radiation produces a photopeak at its energy. The detector also shows response at the lower energies, caused by
416:, or HSE, has issued a user guidance note on selecting the correct radiation measurement instrument for the application concerned. This covers all radiation instrument technologies, and is a useful comparative guide to the use of scintillation detectors.
215:
The number of such pulses per unit time also gives information about the intensity of the radiation. In some applications individual pulses are not counted, but rather only the average current at the anode is used as a measure of radiation intensity.
392:
yards and contamination monitoring of nuclear waste. There are variants of scintillation counters mounted on pick-up trucks and helicopters for rapid response in case of a security situation due to
1082:
510:
tube, and a circuit for measuring the height of the pulses produced by the photomultiplier. The pulses are counted and sorted by their height, producing a x-y plot of scintillator flash
519:, two smaller escape peaks at energies 0.511 and 1.022 MeV below the photopeak for the creation of electron-positron pairs when one or both annihilation photons escape, and a
1062:
80:
Scintillation counters are widely used in radiation protection, assay of radioactive materials and physics research because they can be made inexpensively yet with good
479:
Measurement of gamma ray spectrum with a scintillation counter. A high voltage drives the counter which feeds signals to the
Multichannel Analyser (MCA) and computer.
461:
Scintillation materials are used for ambient gamma dose measurement, though a different construction is used to detect contamination, as no thin window is required.
429:
108:. There was a requirement to measure the radiation from small quantities of uranium, and his innovation was to use one of the newly available highly sensitive
736:
1067:
212:
which integrates the energy information, an output pulse is obtained which is proportional to the energy of the particle exciting the scintillator.
1072:
789:
948:
453:
both hand-held and fixed monitoring equipment, and such instruments are relatively inexpensive compared with the gas proportional detector.
273:(ZnS) is widely used as a detector of alpha particles. Zinc sulfide is the material Rutherford used to perform his scattering experiment.
372:
Scintillation probe being used to measure surface radioactive contamination. The probe is held as close to the object as practicable
691:
1193:
1113:
105:
1077:
1057:
782:
641:
495:
of input energy is fairly constant. By measuring the intensity of the flash (the number of the photons produced by the
441:
Hand-held scintillation counter reading ambient gamma dose. The position of the internal detector is shown by the cross
759:
23:
Schematic showing incident high energy photon hitting a scintillating crystal, triggering the release of low-energy
653:
707:
1098:
671:
433:
Hand-held large area alpha scintillation probe under calibration with a plate source in a bench calibration jig.
880:
1198:
1163:
1108:
1103:
775:
575:
550:
353:
248:
714:
113:
523:
peak. Higher energies can be measured when two or more photons strike the detector almost simultaneously (
131:
of uranium salts in 1896. Previously, scintillation events had to be laboriously detected by eye, using a
1183:
413:
261:(CsI) in crystalline form is used as the scintillator for the detection of protons and alpha particles.
1151:
890:
376:
Scintillation counters are used to measure radiation in a variety of applications including hand held
837:
445:
385:
1147:
1134:
1129:
381:
328:, have better intrinsic energy resolution than scintillators, and are preferred where feasible for
925:
524:
120:
51:
1188:
1155:
1052:
985:
321:
754:
Glenn F Knoll. Radiation
Detection and Measurement, third edition 2000. John Wiley and sons,
1159:
531:
chain), appearing as sum peaks with energies up to the value of two or more photopeaks added
70:
633:
Instrumentation
Between Science, State and Industry (Sociology of the Sciences Yearbook, 22)
77:), which converts the light to an electrical signal and electronics to process this signal.
980:
973:
812:
798:
201:
185:
475:
8:
995:
905:
286:
47:
344:
detectors, high efficiency is gained through the use of scintillating materials rich in
842:
832:
827:
596:
560:
540:
516:
470:
329:
252:
189:
81:
43:
885:
755:
730:
688:
637:
397:
349:
313:
116:
to accurately count the flashes of light from a scintillator subjected to radiation.
101:
19:
1026:
1021:
528:
499:
or gamma photon) it is therefore possible to discern the original photon's energy.
301:
209:
163:
920:
895:
695:
602:
565:
507:
388:, medical imaging, radiometric assay, nuclear security and nuclear plant safety.
224:
193:
168:
128:
109:
66:
32:
1011:
958:
875:
822:
545:
437:
409:
274:
244:
132:
28:
619:
1177:
865:
357:
317:
309:
262:
258:
124:
97:
62:
606:
990:
910:
847:
570:
503:
492:
377:
270:
85:
58:
491:
into high number of lower-energy photons, where the number of photons per
200:
tube which emits at most one electron for each arriving photon due to the
179:
animation of radiation scintillation counter using a photomultiplier tube.
1031:
963:
900:
520:
175:
657:
915:
767:
555:
511:
393:
240:
74:
61:
which generates photons in response to incident radiation, a sensitive
953:
870:
817:
675:
488:
325:
297:
140:
1016:
708:"Selection, use and maintenance of portable monitoring instruments"
345:
305:
266:
151:
96:
The first electronic scintillation counter was invented in 1944 by
1047:
930:
341:
236:
145:
136:
24:
368:
484:
269:
is used as a scintillator for the detection of gamma waves and
308:
in the detector, and certain scintillating materials, such as
496:
320:
of some of the elements of which they are composed. However,
227:
tube carries a detailed description of the tube's operation.
316:, achieve high electron densities as a result of the high
119:
This built upon the work of earlier researchers such as
654:"Automatic Radiation Detection and Monitoring System"
717:. 2001. Archived from the original on 6 October 2012
356:
are an efficient and practical means of quantifying
54:
material, and detecting the resultant light pulses.
239:, usually a phosphor, plastic (usually containing
1175:
735:: CS1 maint: bot: original URL status unknown (
424:
783:
84:, and can measure both the intensity and the
42:is an instrument for detecting and measuring
300:detector (per unit volume) depends upon the
949:Airborne radioactive particulate monitoring
235:The scintillator consists of a transparent
16:Instrument for measuring ionizing radiation
790:
776:
635:. Kluwer Academic Publishers. p. 270.
601:. Academic Press (New York). p. 235.
403:
400:. Hand-held units are also commonly used.
797:
672:"Automatic Radiation Detection Vehicles"
502:The spectrometer consists of a suitable
474:
436:
428:
367:
280:
174:
167:Apparatus with a scintillating crystal,
162:
18:
750:
748:
746:
630:
620:Oxford Dictionary of National Biography
598:Counting tubes, theory and applications
419:
1176:
594:
230:
1114:Radiation Protection Convention, 1960
771:
483:Scintillators often convert a single
143:which were used in metabolic studies
743:
700:
527:, within the time resolution of the
464:
277:(LiI) is used in neutron detectors.
106:University of California at Berkeley
265:(NaI) containing a small amount of
220:incident radiation being measured.
13:
171:, and data acquisition components.
50:effect of incident radiation on a
14:
1210:
322:detectors based on semiconductors
251:) that fluoresces when struck by
363:
881:Computed tomography dose index
682:
664:
646:
624:
613:
588:
27:which are then converted into
1:
715:Health & Safety Executive
689:Portable MicroR Survey Meters
581:
576:Total absorption spectroscopy
551:Liquid scintillation counting
354:Liquid scintillation counters
249:liquid scintillation counting
100:whilst he was working on the
1194:Ionising radiation detectors
425:Alpha and beta contamination
296:The quantum efficiency of a
158:
114:Radio Corporation of America
7:
534:
414:Health and Safety Executive
10:
1215:
1145:
631:Joerges, Bernward (2001).
595:Curran, Samuel C. (1949).
468:
456:
335:
284:
91:
1143:
1122:
1091:
1040:
1004:
939:
856:
838:Radioactive contamination
805:
446:Radioactive contamination
386:radioactive contamination
1146:See also the categories
1135:Radiation-induced cancer
1130:Acute radiation syndrome
382:environmental monitoring
291:
404:Diffusion cloud chamber
378:radiation survey meters
121:Antoine Henri Becquerel
88:of incident radiation.
986:Semiconductor detector
942:measurement techniques
480:
442:
434:
373:
352:neutrons efficiently.
330:gamma-ray spectrometry
180:
172:
127:whilst working on the
35:
31:and multiplied in the
1005:Protection techniques
969:Scintillation counter
478:
440:
432:
371:
281:Detector efficiencies
178:
166:
71:charge-coupled device
40:scintillation counter
22:
1199:Radiation protection
1164:Radiation protection
981:Radiation monitoring
974:Proportional counter
859:quantities and units
813:Background radiation
799:Radiation protection
420:Radiation protection
324:, notably hyperpure
202:photoelectric effect
186:photoelectric effect
996:Whole-body counting
906:Mean glandular dose
843:Radioactive sources
287:Counting efficiency
231:Detection materials
223:The article on the
73:(CCD) camera, or a
1184:Particle detectors
833:Internal dosimetry
828:Ionizing radiation
694:2009-12-07 at the
561:Pandemonium effect
541:Gamma spectroscopy
517:Compton scattering
481:
471:Gamma spectroscopy
443:
435:
374:
253:ionizing radiation
190:Compton scattering
181:
173:
123:, who discovered
112:tubes made by the
82:quantum efficiency
44:ionizing radiation
36:
1171:
1170:
1152:Radiation effects
1123:Radiation effects
886:Counts per minute
465:As a spectrometer
398:radioactive waste
314:bismuth germanate
102:Manhattan Project
98:Sir Samuel Curran
57:It consists of a
1206:
1027:Radon mitigation
1022:Potassium iodide
940:Instruments and
792:
785:
778:
769:
768:
762:
752:
741:
740:
734:
726:
724:
722:
712:
704:
698:
686:
680:
679:
674:. Archived from
668:
662:
661:
656:. Archived from
650:
644:
636:
628:
622:
617:
611:
610:
592:
529:data acquisition
493:megaelectronvolt
380:, personnel and
210:charge amplifier
1214:
1213:
1209:
1208:
1207:
1205:
1204:
1203:
1174:
1173:
1172:
1167:
1166:
1148:Medical physics
1139:
1118:
1087:
1036:
1000:
941:
935:
896:Equivalent dose
858:
852:
801:
796:
766:
765:
753:
744:
728:
727:
720:
718:
710:
706:
705:
701:
696:Wayback Machine
687:
683:
670:
669:
665:
652:
651:
647:
629:
625:
618:
614:
593:
589:
584:
566:Photon counting
537:
508:photomultiplier
487:of high energy
473:
467:
459:
427:
422:
406:
366:
340:In the case of
338:
294:
289:
283:
233:
225:photomultiplier
194:pair production
169:photomultiplier
161:
129:phosphorescence
110:photomultiplier
94:
67:photomultiplier
33:photomultiplier
17:
12:
11:
5:
1212:
1202:
1201:
1196:
1191:
1186:
1169:
1168:
1144:
1141:
1140:
1138:
1137:
1132:
1126:
1124:
1120:
1119:
1117:
1116:
1111:
1106:
1101:
1095:
1093:
1089:
1088:
1086:
1085:
1080:
1075:
1070:
1065:
1060:
1055:
1050:
1044:
1042:
1038:
1037:
1035:
1034:
1029:
1024:
1019:
1014:
1012:Lead shielding
1008:
1006:
1002:
1001:
999:
998:
993:
988:
983:
977:
976:
971:
966:
961:
959:Geiger counter
956:
951:
945:
943:
937:
936:
934:
933:
928:
923:
918:
913:
908:
903:
898:
893:
891:Effective dose
888:
883:
878:
876:Committed dose
873:
868:
862:
860:
854:
853:
851:
850:
845:
840:
835:
830:
825:
823:Health physics
820:
815:
809:
807:
803:
802:
795:
794:
787:
780:
772:
764:
763:
742:
699:
681:
678:on 2014-08-14.
663:
660:on 2014-08-14.
645:
642:978-1402002427
623:
612:
586:
585:
583:
580:
579:
578:
573:
568:
563:
558:
553:
548:
546:Geiger counter
543:
536:
533:
469:Main article:
466:
463:
458:
455:
426:
423:
421:
418:
410:United Kingdom
405:
402:
365:
362:
358:beta radiation
337:
334:
318:atomic numbers
293:
290:
282:
279:
275:Lithium iodide
245:organic liquid
232:
229:
160:
157:
133:spinthariscope
93:
90:
69:tube (PMT), a
29:photoelectrons
15:
9:
6:
4:
3:
2:
1211:
1200:
1197:
1195:
1192:
1190:
1189:Spectrometers
1187:
1185:
1182:
1181:
1179:
1165:
1161:
1157:
1156:Radioactivity
1153:
1149:
1142:
1136:
1133:
1131:
1128:
1127:
1125:
1121:
1115:
1112:
1110:
1107:
1105:
1102:
1100:
1097:
1096:
1094:
1090:
1084:
1081:
1079:
1076:
1074:
1071:
1069:
1066:
1064:
1061:
1059:
1056:
1054:
1051:
1049:
1046:
1045:
1043:
1041:Organisations
1039:
1033:
1030:
1028:
1025:
1023:
1020:
1018:
1015:
1013:
1010:
1009:
1007:
1003:
997:
994:
992:
989:
987:
984:
982:
979:
978:
975:
972:
970:
967:
965:
962:
960:
957:
955:
952:
950:
947:
946:
944:
938:
932:
929:
927:
924:
922:
919:
917:
914:
912:
909:
907:
904:
902:
899:
897:
894:
892:
889:
887:
884:
882:
879:
877:
874:
872:
869:
867:
866:Absorbed dose
864:
863:
861:
855:
849:
846:
844:
841:
839:
836:
834:
831:
829:
826:
824:
821:
819:
816:
814:
811:
810:
808:
806:Main articles
804:
800:
793:
788:
786:
781:
779:
774:
773:
770:
761:
760:0-471-07338-5
757:
751:
749:
747:
738:
732:
716:
709:
703:
697:
693:
690:
685:
677:
673:
667:
659:
655:
649:
643:
639:
634:
627:
621:
616:
608:
604:
600:
599:
591:
587:
577:
574:
572:
569:
567:
564:
562:
559:
557:
554:
552:
549:
547:
544:
542:
539:
538:
532:
530:
526:
522:
518:
513:
509:
505:
500:
498:
494:
490:
486:
477:
472:
462:
454:
450:
447:
439:
431:
417:
415:
411:
401:
399:
395:
389:
387:
383:
379:
370:
361:
359:
355:
351:
347:
343:
333:
331:
327:
323:
319:
315:
311:
310:sodium iodide
307:
303:
299:
288:
278:
276:
272:
268:
264:
263:Sodium iodide
260:
259:Cesium iodide
256:
254:
250:
246:
242:
238:
228:
226:
221:
217:
213:
211:
205:
203:
197:
195:
191:
187:
177:
170:
165:
156:
154:
153:
148:
147:
142:
138:
134:
130:
126:
125:radioactivity
122:
117:
115:
111:
107:
103:
99:
89:
87:
83:
78:
76:
72:
68:
64:
63:photodetector
60:
55:
53:
52:scintillating
49:
46:by using the
45:
41:
34:
30:
26:
21:
1160:Radiobiology
991:Survey meter
968:
911:Monitor unit
857:Measurement
848:Radiobiology
719:. Retrieved
702:
684:
676:the original
666:
658:the original
648:
632:
626:
615:
597:
590:
571:Scintigraphy
504:scintillator
501:
482:
460:
451:
444:
407:
390:
375:
364:Applications
339:
295:
271:zinc sulfide
257:
234:
222:
218:
214:
206:
198:
182:
150:
144:
118:
95:
79:
59:scintillator
56:
39:
37:
1032:Respirators
964:Ion chamber
521:backscatter
506:crystal, a
394:dirty bombs
65:(usually a
1178:Categories
1092:Regulation
582:References
556:Lucas cell
512:brightness
285:See also:
241:anthracene
75:photodiode
48:excitation
1104:NRC (USA)
1053:HPS (USA)
954:Dosimeter
871:Becquerel
818:Dosimetry
721:6 October
607:17868379M
489:radiation
326:germanium
306:electrons
298:gamma-ray
159:Operation
141:carbon-14
1109:ONR (UK)
1099:IRR (UK)
1078:SRP (UK)
1017:Glovebox
921:Roentgen
731:cite web
692:Archived
535:See also
346:hydrogen
267:thallium
152:in vitro
1083:UNSCEAR
1048:Euratom
931:Sievert
525:pile-up
408:In the
350:scatter
342:neutron
336:Neutron
302:density
237:crystal
146:in vivo
137:tritium
104:at the
92:History
25:photons
1162:, and
758:
640:
605:
485:photon
412:, the
86:energy
711:(PDF)
497:x-ray
457:Gamma
348:that
292:Gamma
247:(see
243:) or
1073:IRPA
1068:ICRP
1063:ICRU
1058:IAEA
901:Gray
756:ISBN
737:link
723:2012
638:ISBN
384:for
312:and
149:and
139:and
926:Rem
916:Rad
396:or
304:of
192:or
1180::
1158:,
1154:,
1150:,
745:^
733:}}
729:{{
713:.
603:OL
360:.
332:.
255:.
196:.
188:,
155:.
38:A
791:e
784:t
777:v
739:)
725:.
609:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
