156:
386:
1614:
402:
422:
1626:
1578:
1602:
155:
438:
experiment, using at least two instruments monitoring neutron intensities with audible alerts, and preparing a plan for operating methods and any contingencies that might occur during similar experiments. Additionally, discussions and designs for remote-controlled test devices were initiated, eventually leading to the creation of the
385:
335:
bricks in an incremental fashion around a plutonium core. The purpose of the neutron reflector was to reduce the mass required for the plutonium core to attain criticality. He was moving the final brick over the assembly, but neutron counters alerted
Daghlian to the fact that the addition of that
437:
As a result of the incident, safety regulations for the project were scrutinized and revised. A special committee was established to review any similar experiments and recommend appropriate safety procedures. This change of procedures included needing a minimum of two people involved in such an
456:
In 2000, the city of New London erected a memorial stone and flagpole in
Calkins Park to honor Daghlian. His surname is misspelled "Daghiian" on the monument. The monument bears an inscription: "though not in uniform, he died in service to his country."
421:
375:, and his sister and widowed mother were flown out to care for him. He fell into a coma and died 25 days after the accident. He was the first known fatality caused by a criticality accident. His body was returned to New London, where he was buried at
44:
401:
340:. As he withdrew his hand, he inadvertently dropped the brick onto the center of the assembly. Since the assembly was nearly in the critical state, the accidental addition of that brick caused the reaction to go immediately into the
351:
Daghlian reacted immediately after dropping the brick and attempted to knock the brick off the assembly without success. He was forced to disassemble part of the tungsten-carbide pile in order to halt the reaction.
1453:
1676:
1515:
427:
Harry K. Daghlian's blistered and burnt hand, photographed on August 30, 1945, after he received his fatal radiation dose. He died 16 days after this photo was taken.
395:(with sunglasses) and Harry Daghlian Jr. (seated middle) during the Trinity Test preparation in July 1945. Both physicists died following supercriticality accidents.
376:
118:
449:, a colleague of Daghlian's, was killed in 1946 while performing criticality tests on the same plutonium core. After these two incidents it became known as the "
1468:
1701:
1666:
1716:
1696:
1691:
1033:
895:
1721:
1681:
1360:
1656:
839:
786:
1613:
679:
280:
128:
1661:
453:", and all similar criticality experiments were halted until remote-controlled assembly devices were more fully developed and available.
746:
619:
McLaughlin, Thomas P.; Monahan, Shean P.; Pruvost, Norman L.; Frolov, Vladimir V.; Ryazanov, Boris G.; Sviridov, Victor I. (May 2000),
530:
584:
1711:
1686:
913:
726:
637:
562:
888:
633:
501:
271:. He had a sister, Helen, and a brother, Edward. Soon after his birth the family moved across state to the coastal town of
1592:
1671:
1520:
671:
1488:
230:
779:
A Summary of
Accidents and Incidents Involving Radiation in Atomic Energy Activities, June 1945 through December 1955
1581:
881:
1630:
1606:
1463:
1458:
356:
1545:
1078:
937:
108:
1540:
1437:
992:
445:
These changes did not prevent another criticality accident from happening at Los Alamos the following year.
288:
272:
160:
1319:
987:
982:
977:
952:
629:
250:
168:
96:
77:
1560:
1385:
1128:
1073:
312:
203:
275:. He was educated at Harbor Elementary School, where he played violin in the school orchestra, and at
1651:
1646:
1370:
1365:
1224:
1098:
835:
782:
751:
714:
589:
535:
345:
226:
218:
164:
1229:
1184:
1144:
967:
372:
296:
211:
136:
1706:
1294:
1118:
1088:
1028:
1509:
1498:
1405:
1309:
1264:
1259:
1209:
1058:
1053:
1043:
904:
808:
722:
675:
364:
328:
316:
300:
292:
183:
132:
287:, which was then emerging as an exciting new field. This interest led him to transfer to the
1530:
1329:
1314:
1279:
1254:
1108:
1063:
798:
790:
412:
332:
284:
222:
1535:
1375:
1339:
1269:
1204:
1194:
1169:
1068:
1048:
1023:
718:
707:
368:
341:
276:
1284:
620:
474:
1618:
1478:
1473:
1244:
1179:
1174:
1093:
1018:
947:
558:
17:
1640:
1493:
1355:
1324:
1304:
1249:
1239:
1149:
1038:
1013:
957:
778:
439:
337:
199:
1550:
1432:
1289:
1234:
1214:
1199:
1103:
927:
868:
803:
446:
392:
238:
191:
163:
plug containing the plutonium pit and initiator into a car for transport from the
665:
283:, intending to study mathematics, but became interested in physics, particularly
1380:
1334:
1299:
1274:
1219:
1123:
1113:
997:
740:
738:
308:
195:
187:
864:
43:
1483:
1427:
1164:
1154:
1083:
450:
255:
234:
207:
1525:
1391:
1159:
962:
408:
327:
During an experiment on August 21, 1945, Daghlian was attempting to build a
304:
264:
260:
179:
147:
159:
Herbert Lehr (left) and Harry
Daghlian Jr. (right), loading the assembled
1565:
1398:
932:
1555:
1422:
360:
812:
941:
667:
The
Prometheus Bomb: The Manhattan Project and Government in the Dark
268:
873:
794:
299:
degree in 1942. He then commenced work on his doctorate, assisting
371:. Despite intensive medical care, he developed symptoms of severe
154:
1503:
972:
259:
Currie) and
Haroutune Krikor Daghlian. His father was an ethnic
877:
355:
Daghlian was estimated to have received a dose of 510
253:, on May 4, 1921, one of three children of Margaret Rose (
1677:
Burials at Cedar Grove
Cemetery (New London, Connecticut)
331:
manually by stacking a set of 4.4-kilogram (9.7 lb)
237:", was later involved in the death of another physicist,
659:
657:
415:
blocks in a re-enactment of
Daghlian's 1945 experiment
1590:
307:. In 1944, while still a graduate student, he joined
1446:
1415:
1348:
1137:
1006:
920:
524:
522:
178:(May 4, 1921 – September 15, 1945) was an American
143:
124:
114:
104:
85:
59:
34:
706:
502:"A death in the desert that 'Oppenheimer' ignored"
772:
770:
344:region of neutronic behavior. This resulted in a
747:"A quiet victim of a horrific war he helped end"
709:Under the Cloud: The Decades of Nuclear Testing
889:
531:"NL man was 1st victim of atomic experiments"
221:that occurred when he accidentally dropped a
8:
279:. In 1938, at the age of 17, he entered the
700:
698:
249:Haroutune Krikor Daghlian Jr., was born in
202:experiment at the remote Omega Site of the
896:
882:
874:
210:and died 25 days later from the resultant
42:
31:
802:
233:. This core, subsequently nicknamed the "
217:Daghlian was irradiated as a result of a
614:
612:
610:
608:
585:"Harry Daghlian, Jr., wins Purdue honor"
1597:
643:from the original on September 27, 2007
466:
381:
281:Massachusetts Institute of Technology
198:himself on August 21, 1945, during a
129:Massachusetts Institute of Technology
7:
565:from the original on August 30, 2015
1702:People from New London, Connecticut
1667:American people of Armenian descent
1717:Deaths by acute radiation syndrome
1697:People from Waterbury, Connecticut
1692:People from Los Alamos, New Mexico
1361:Bombings of Hiroshima and Nagasaki
842:from the original on April 7, 2014
311:'s Critical Assembly Group at the
186:, which designed and produced the
25:
745:Slosberg, Steven (June 8, 2000).
622:A Review of Criticality Accidents
411:surrounded by neutron-reflecting
295:, from which he graduated with a
1722:20th-century American physicists
1682:Deaths from laboratory accidents
1624:
1612:
1600:
1577:
1576:
777:Hayes, Daniel F. (August 1956).
529:Baumann, Paul (August 6, 1985).
481:. September 19, 1945. p. 11
420:
400:
384:
1657:Accidental deaths in New Mexico
634:Los Alamos National Laboratory
561:. Atomic Heritage Foundation.
475:"Article clipped from The Day"
336:brick would render the system
323:Criticality accident and death
27:American physicist (1921–1945)
1:
787:U.S. Atomic Energy Commission
176:Haroutune Krikor Daghlian Jr.
64:Haroutune Krikor Daghlian Jr.
49:
1521:Oppenheimer security hearing
717:: Two Sixty Press. pp.
672:University of Nebraska Press
636:, pp. 74–75, LA-13638,
1662:American nuclear physicists
705:Miller, Richard L. (1991).
1738:
836:"The Third Core's Revenge"
664:Sullivan, Neil J. (2016).
593:. April 1, 1941. p. 3
1574:
1464:Bismuth phosphate process
1459:Atomic Energy Act of 1946
911:
225:brick onto a 6.2 kg
41:
1712:Purdue University alumni
1687:Manhattan Project people
838:. Restricted data blog.
245:Early life and education
109:Acute radiation syndrome
1541:S-1 Executive Committee
1489:Einstein–Szilard letter
804:2027/mdp.39015095051879
289:West Lafayette, Indiana
273:New London, Connecticut
231:plutonium–gallium alloy
983:Salt Wells Pilot Plant
630:Los Alamos, New Mexico
251:Waterbury, Connecticut
172:
97:Los Alamos, New Mexico
78:Waterbury, Connecticut
18:Harry K. Daghlian, Jr.
1561:X-10 Graphite Reactor
1516:Nobel Prize laureates
1386:509th Composite Group
367:, from a yield of 10
313:Los Alamos Laboratory
204:Los Alamos Laboratory
158:
1469:British contribution
1371:Operation Peppermint
1366:Operation Crossroads
1225:Maria Goeppert Mayer
783:Oak Ridge, Tennessee
715:The Woodlands, Texas
377:Cedar Grove Cemetery
346:criticality accident
277:Bulkeley High School
219:criticality accident
165:McDonald ranch house
119:Cedar Grove Cemetery
1672:Armenian physicists
1230:George Kistiakowsky
1185:Charles Critchfield
834:Wellerstein, Alex.
391:The two physicists
373:radiation poisoning
297:Bachelor of Science
212:radiation poisoning
105:Cause of death
1631:History of science
1607:Nuclear technology
1295:Henry DeWolf Smyth
1074:Robert Oppenheimer
1029:Priscilla Duffield
674:. pp. 14–16.
194:. He accidentally
190:that were used in
173:
89:September 15, 1945
1588:
1587:
1510:Los Alamos Primer
1499:Interim Committee
1454:African Americans
1406:The Great Artiste
1265:Isidor Isaac Rabi
1260:Norman Ramsey Jr.
1059:Franklin Matthias
998:Heavy water sites
905:Manhattan Project
681:978-1-61234-890-2
365:neutron radiation
329:neutron reflector
317:Manhattan Project
301:Marshall Holloway
293:Purdue University
184:Manhattan Project
171:on July 13, 1945.
153:
152:
133:Purdue University
16:(Redirected from
1729:
1629:
1628:
1627:
1617:
1616:
1605:
1604:
1603:
1596:
1580:
1579:
1531:Quebec Agreement
1315:John von Neumann
1255:George B. Pegram
1064:Dorothy McKibbin
898:
891:
884:
875:
852:
851:
849:
847:
831:
825:
824:
822:
820:
806:
789:. pp. 2–3.
774:
765:
764:
762:
760:
742:
733:
732:
712:
702:
693:
692:
690:
688:
661:
652:
651:
650:
648:
642:
627:
616:
603:
602:
600:
598:
581:
575:
574:
572:
570:
559:"Harry Daghlian"
555:
549:
548:
546:
544:
526:
517:
516:
514:
512:
497:
491:
490:
488:
486:
471:
424:
413:tungsten carbide
404:
388:
333:tungsten carbide
285:particle physics
223:tungsten carbide
92:
73:
71:
54:
51:
46:
32:
21:
1737:
1736:
1732:
1731:
1730:
1728:
1727:
1726:
1637:
1636:
1635:
1625:
1623:
1611:
1601:
1599:
1591:
1589:
1584:
1570:
1536:RaLa Experiment
1442:
1411:
1376:Project Alberta
1344:
1340:Chien-Shiung Wu
1270:James Rainwater
1205:Richard Feynman
1195:John R. Dunning
1170:Norris Bradbury
1133:
1119:Stafford Warren
1089:William Purnell
1069:Kenneth Nichols
1049:Ernest Lawrence
1024:James B. Conant
1002:
916:
907:
902:
861:
856:
855:
845:
843:
833:
832:
828:
818:
816:
795:10.2172/4343762
776:
775:
768:
758:
756:
744:
743:
736:
729:
704:
703:
696:
686:
684:
682:
663:
662:
655:
646:
644:
640:
625:
618:
617:
606:
596:
594:
583:
582:
578:
568:
566:
557:
556:
552:
542:
540:
539:. pp. 1, 4
528:
527:
520:
510:
508:
499:
498:
494:
484:
482:
473:
472:
468:
463:
435:
428:
425:
416:
405:
396:
389:
342:prompt critical
325:
267:in what is now
247:
131:
100:
94:
90:
81:
75:
69:
67:
66:
65:
55:
52:
37:
28:
23:
22:
15:
12:
11:
5:
1735:
1733:
1725:
1724:
1719:
1714:
1709:
1704:
1699:
1694:
1689:
1684:
1679:
1674:
1669:
1664:
1659:
1654:
1649:
1639:
1638:
1634:
1633:
1621:
1609:
1586:
1585:
1575:
1572:
1571:
1569:
1568:
1563:
1558:
1553:
1548:
1543:
1538:
1533:
1528:
1523:
1518:
1513:
1506:
1501:
1496:
1491:
1486:
1481:
1479:Chicago Pile-1
1476:
1474:Calutron Girls
1471:
1466:
1461:
1456:
1450:
1448:
1447:Related topics
1444:
1443:
1441:
1440:
1435:
1430:
1425:
1419:
1417:
1413:
1412:
1410:
1409:
1402:
1395:
1388:
1383:
1378:
1373:
1368:
1363:
1358:
1352:
1350:
1346:
1345:
1343:
1342:
1337:
1332:
1327:
1322:
1317:
1312:
1310:Stanisław Ulam
1307:
1302:
1297:
1292:
1287:
1282:
1277:
1272:
1267:
1262:
1257:
1252:
1247:
1245:Edwin McMillan
1242:
1237:
1232:
1227:
1222:
1217:
1212:
1207:
1202:
1197:
1192:
1190:Harry Daghlian
1187:
1182:
1180:John Cockcroft
1177:
1175:James Chadwick
1172:
1167:
1162:
1157:
1152:
1147:
1141:
1139:
1135:
1134:
1132:
1131:
1126:
1121:
1116:
1111:
1106:
1101:
1099:Charles Thomas
1096:
1094:Frank Spedding
1091:
1086:
1081:
1076:
1071:
1066:
1061:
1056:
1054:James Marshall
1051:
1046:
1041:
1036:
1034:Thomas Farrell
1031:
1026:
1021:
1019:Arthur Compton
1016:
1010:
1008:
1007:Administrators
1004:
1003:
1001:
1000:
995:
990:
985:
980:
975:
970:
965:
960:
955:
950:
945:
935:
930:
924:
922:
918:
917:
912:
909:
908:
903:
901:
900:
893:
886:
878:
872:
871:
865:Harry Daghlian
860:
859:External links
857:
854:
853:
826:
766:
734:
727:
694:
680:
653:
604:
576:
550:
518:
506:www.theday.com
492:
465:
464:
462:
459:
434:
431:
430:
429:
426:
419:
417:
407:The sphere of
406:
399:
397:
390:
383:
324:
321:
246:
243:
169:the shot tower
151:
150:
145:
141:
140:
126:
122:
121:
116:
112:
111:
106:
102:
101:
95:
93:(aged 24)
87:
83:
82:
76:
63:
61:
57:
56:
47:
39:
38:
36:Harry Daghlian
35:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1734:
1723:
1720:
1718:
1715:
1713:
1710:
1708:
1705:
1703:
1700:
1698:
1695:
1693:
1690:
1688:
1685:
1683:
1680:
1678:
1675:
1673:
1670:
1668:
1665:
1663:
1660:
1658:
1655:
1653:
1650:
1648:
1645:
1644:
1642:
1632:
1622:
1620:
1615:
1610:
1608:
1598:
1594:
1583:
1573:
1567:
1564:
1562:
1559:
1557:
1554:
1552:
1549:
1547:
1544:
1542:
1539:
1537:
1534:
1532:
1529:
1527:
1524:
1522:
1519:
1517:
1514:
1512:
1511:
1507:
1505:
1502:
1500:
1497:
1495:
1494:Franck Report
1492:
1490:
1487:
1485:
1482:
1480:
1477:
1475:
1472:
1470:
1467:
1465:
1462:
1460:
1457:
1455:
1452:
1451:
1449:
1445:
1439:
1436:
1434:
1431:
1429:
1426:
1424:
1421:
1420:
1418:
1414:
1408:
1407:
1403:
1401:
1400:
1396:
1394:
1393:
1389:
1387:
1384:
1382:
1379:
1377:
1374:
1372:
1369:
1367:
1364:
1362:
1359:
1357:
1356:Alsos Mission
1354:
1353:
1351:
1347:
1341:
1338:
1336:
1333:
1331:
1330:Robert Wilson
1328:
1326:
1325:Eugene Wigner
1323:
1321:
1318:
1316:
1313:
1311:
1308:
1306:
1305:Edward Teller
1303:
1301:
1298:
1296:
1293:
1291:
1288:
1286:
1283:
1281:
1280:Glenn Seaborg
1278:
1276:
1273:
1271:
1268:
1266:
1263:
1261:
1258:
1256:
1253:
1251:
1250:Mark Oliphant
1248:
1246:
1243:
1241:
1240:Willard Libby
1238:
1236:
1233:
1231:
1228:
1226:
1223:
1221:
1218:
1216:
1213:
1211:
1208:
1206:
1203:
1201:
1198:
1196:
1193:
1191:
1188:
1186:
1183:
1181:
1178:
1176:
1173:
1171:
1168:
1166:
1163:
1161:
1158:
1156:
1153:
1151:
1150:Robert Bacher
1148:
1146:
1143:
1142:
1140:
1136:
1130:
1129:Roscoe Wilson
1127:
1125:
1122:
1120:
1117:
1115:
1112:
1110:
1107:
1105:
1102:
1100:
1097:
1095:
1092:
1090:
1087:
1085:
1082:
1080:
1077:
1075:
1072:
1070:
1067:
1065:
1062:
1060:
1057:
1055:
1052:
1050:
1047:
1045:
1044:John Lansdale
1042:
1040:
1039:Leslie Groves
1037:
1035:
1032:
1030:
1027:
1025:
1022:
1020:
1017:
1015:
1014:Vannevar Bush
1012:
1011:
1009:
1005:
999:
996:
994:
991:
989:
986:
984:
981:
979:
976:
974:
971:
969:
966:
964:
961:
959:
956:
954:
951:
949:
946:
943:
939:
936:
934:
931:
929:
926:
925:
923:
919:
915:
910:
906:
899:
894:
892:
887:
885:
880:
879:
876:
870:
866:
863:
862:
858:
841:
837:
830:
827:
814:
810:
805:
800:
796:
792:
788:
784:
780:
773:
771:
767:
754:
753:
748:
741:
739:
735:
730:
728:0-02-921620-6
724:
720:
716:
711:
710:
701:
699:
695:
683:
677:
673:
669:
668:
660:
658:
654:
639:
635:
631:
624:
623:
615:
613:
611:
609:
605:
592:
591:
586:
580:
577:
564:
560:
554:
551:
538:
537:
532:
525:
523:
519:
507:
503:
500:Howard, Lee.
496:
493:
480:
476:
470:
467:
460:
458:
454:
452:
448:
443:
441:
440:Godiva device
432:
423:
418:
414:
410:
403:
398:
394:
387:
382:
380:
378:
374:
370:
366:
362:
358:
353:
349:
347:
343:
339:
338:supercritical
334:
330:
322:
320:
318:
314:
310:
306:
302:
298:
294:
290:
286:
282:
278:
274:
270:
266:
262:
258:
257:
252:
244:
242:
240:
236:
232:
228:
224:
220:
215:
213:
209:
205:
201:
200:critical mass
197:
193:
189:
185:
181:
177:
170:
166:
162:
157:
149:
146:
142:
138:
134:
130:
127:
123:
120:
117:
115:Resting place
113:
110:
107:
103:
98:
88:
84:
79:
62:
58:
45:
40:
33:
30:
19:
1566:Y-12 Project
1551:Smyth Report
1546:S-50 Project
1508:
1504:K-25 Project
1433:Pumpkin bomb
1404:
1397:
1390:
1320:John Wheeler
1290:Louis Slotin
1285:Emilio Segrè
1235:George Koval
1215:James Franck
1200:Enrico Fermi
1189:
1145:Luis Alvarez
1104:Paul Tibbets
1079:Deak Parsons
869:Find a Grave
844:. Retrieved
829:
817:. Retrieved
757:. Retrieved
755:. p. C1
750:
708:
687:November 30,
685:. Retrieved
666:
645:, retrieved
621:
595:. Retrieved
588:
579:
567:. Retrieved
553:
541:. Retrieved
534:
509:. Retrieved
505:
495:
483:. Retrieved
478:
469:
455:
447:Louis Slotin
444:
436:
393:Louis Slotin
354:
350:
326:
291:, campus of
254:
248:
239:Louis Slotin
216:
192:World War II
188:atomic bombs
175:
174:
91:(1945-09-15)
29:
1652:1945 deaths
1647:1921 births
1381:Silverplate
1335:Leona Woods
1300:Leo Szilard
1275:Bruno Rossi
1220:Klaus Fuchs
1124:Ed Westcott
1114:Harold Urey
670:. Lincoln:
309:Otto Frisch
74:May 4, 1921
53: 1944
1641:Categories
1484:Demon core
1428:Little Boy
1349:Operations
1165:Niels Bohr
1155:Hans Bethe
1138:Scientists
1084:Boris Pash
963:Los Alamos
815:. TID-5360
781:(Report).
759:August 15,
719:68, 69, 77
597:August 15,
569:August 15,
543:August 15,
461:References
451:demon core
359:(5.1
305:cyclotrons
235:demon core
208:New Mexico
196:irradiated
144:Occupation
70:1921-05-04
1707:Plutonium
1526:Plutonium
1392:Enola Gay
1210:Val Fitch
1160:Aage Bohr
1109:Bud Uanna
978:Oak Ridge
819:August 8,
647:April 21,
409:plutonium
303:with the
265:Gaziantep
227:bomb core
182:with the
180:physicist
148:Physicist
125:Education
48:Daghlian
1582:Category
1438:Thin Man
1399:Bockscar
993:Wendover
973:New York
968:Montreal
958:Inyokern
933:Berkeley
914:Timeline
846:April 4,
840:Archived
638:archived
563:Archived
369:fissions
261:Armenian
229:made of
1619:Physics
1593:Portals
1556:Uranium
1423:Fat Man
1416:Weapons
988:Trinity
953:Hanford
938:Chicago
813:4343762
752:The Day
590:The Day
536:The Day
511:July 1,
485:July 1,
479:The Day
315:of the
948:Dayton
942:Site A
811:
725:
678:
433:Legacy
269:Turkey
161:tamper
99:, U.S.
80:, U.S.
921:Sites
641:(PDF)
626:(PDF)
363:) of
263:from
928:Ames
848:2014
821:2015
809:OSTI
761:2015
723:ISBN
689:2021
676:ISBN
649:2010
599:2015
571:2015
545:2015
513:2024
487:2024
86:Died
60:Born
867:at
799:hdl
791:doi
357:rem
256:née
206:in
167:to
1643::
807:.
797:.
785::
769:^
749:.
737:^
721:.
713:.
697:^
656:^
632::
628:,
607:^
587:.
533:.
521:^
504:.
477:.
442:.
379:.
361:Sv
348:.
319:.
241:.
214:.
137:BS
50:c.
1595::
944:)
940:(
897:e
890:t
883:v
850:.
823:.
801::
793::
763:.
731:.
691:.
601:.
573:.
547:.
515:.
489:.
139:)
135:(
72:)
68:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
