145:
375:
1603:
391:
411:
1615:
1567:
1591:
427:
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
324:
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
426:
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
33:
374:
144:
445:
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."
364:, 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
410:
329:. 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
390:
340:
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.
1442:
1665:
1504:
416:
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.
384:(with sunglasses) and Harry Daghlian Jr. (seated middle) during the Trinity Test preparation in July 1945. Both physicists died following supercriticality accidents.
438:, 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 "
828:
365:
107:
1457:
1690:
1655:
1705:
1685:
1680:
1022:
884:
442:", and all similar criticality experiments were halted until remote-controlled assembly devices were more fully developed and available.
735:
608:
McLaughlin, Thomas P.; Monahan, Shean P.; Pruvost, Norman L.; Frolov, Vladimir V.; Ryazanov, Boris G.; Sviridov, Victor I. (May 2000),
519:
1710:
1670:
1349:
573:
626:
1645:
551:
775:
668:
490:
269:
117:
1650:
260:. He had a sister, Helen, and a brother, Edward. Soon after his birth the family moved across state to the coastal town of
1700:
1675:
902:
768:
A Summary of
Accidents and Incidents Involving Radiation in Atomic Energy Activities, June 1945 through December 1955
715:
1602:
877:
622:
434:
These changes did not prevent another criticality accident from happening at Los Alamos the following year.
1660:
1509:
660:
1477:
219:
1581:
1570:
870:
264:. He was educated at Harbor Elementary School, where he played violin in the school orchestra, and at
1619:
1595:
1452:
1447:
824:
345:
1534:
1067:
926:
97:
1529:
1426:
981:
277:
261:
149:
1308:
976:
971:
966:
941:
618:
239:
157:
85:
66:
1549:
1374:
1117:
1062:
301:
276:, which was then emerging as an exciting new field. This interest led him to transfer to the
192:
1640:
1635:
1359:
1354:
1213:
1087:
771:
740:
703:
578:
524:
334:
215:
207:
153:
707:
696:
8:
1218:
1173:
1133:
956:
609:
361:
285:
200:
125:
463:
1695:
1283:
1107:
1077:
1017:
547:
1498:
1487:
1394:
1253:
1248:
1198:
1047:
1042:
1032:
893:
797:
767:
711:
664:
353:
317:
305:
289:
281:
172:
121:
1298:
1519:
1318:
1303:
1268:
1243:
1097:
1052:
792:
787:
779:
401:
321:
273:
211:
152:
plug containing the plutonium pit and initiator into a car for transport from the
1524:
1364:
1328:
1258:
1193:
1183:
1158:
1057:
1037:
1012:
654:
357:
330:
272:, intending to study mathematics, but became interested in physics, particularly
265:
1273:
729:
727:
1607:
1467:
1462:
1233:
1168:
1163:
1082:
1007:
936:
853:
1629:
1482:
1344:
1313:
1293:
1238:
1228:
1138:
1027:
1002:
946:
724:
428:
326:
188:
316:
During an experiment on August 21, 1945, Daghlian was attempting to build a
1539:
1421:
1278:
1223:
1203:
1188:
1092:
916:
857:
435:
381:
227:
180:
148:
Herbert Lehr (left) and Harry
Daghlian Jr. (right), loading the assembled
1369:
1323:
1288:
1263:
1208:
1112:
1102:
986:
297:
184:
176:
1472:
1416:
1153:
1143:
1072:
439:
244:
223:
196:
801:
1514:
1380:
1148:
951:
656:
The
Prometheus Bomb: The Manhattan Project and Government in the Dark
397:
293:
253:
249:
168:
136:
862:
783:
1554:
1387:
921:
288:
degree in 1942. He then commenced work on his doctorate, assisting
32:
360:. Despite intensive medical care, he developed symptoms of severe
1544:
1411:
349:
248:
Currie) and
Haroutune Krikor Daghlian. His father was an ethnic
930:
257:
607:
1492:
961:
344:
Daghlian was estimated to have received a dose of 510
242:, on May 4, 1921, one of three children of Margaret Rose (
1666:
Burials at Cedar Grove
Cemetery (New London, Connecticut)
320:
manually by stacking a set of 4.4-kilogram (9.7 lb)
226:", was later involved in the death of another physicist,
648:
646:
404:
blocks in a re-enactment of
Daghlian's 1945 experiment
1579:
643:
296:. In 1944, while still a graduate student, he joined
513:
511:
167:(May 4, 1921 – September 15, 1945) was an American
695:
491:"A death in the desert that 'Oppenheimer' ignored"
761:
759:
333:region of neutronic behavior. This resulted in a
311:
1627:
736:"A quiet victim of a horrific war he helped end"
508:
698:Under the Cloud: The Decades of Nuclear Testing
756:
878:
520:"NL man was 1st victim of atomic experiments"
210:that occurred when he accidentally dropped a
268:. In 1938, at the age of 17, he entered the
689:
687:
238:Haroutune Krikor Daghlian Jr., was born in
233:
191:experiment at the remote Omega Site of the
885:
871:
199:and died 25 days later from the resultant
31:
791:
222:. This core, subsequently nicknamed the "
206:Daghlian was irradiated as a result of a
733:
684:
652:
603:
601:
599:
597:
574:"Harry Daghlian, Jr., wins Purdue honor"
143:
822:
632:from the original on September 27, 2007
517:
1628:
693:
892:
866:
816:
765:
594:
270:Massachusetts Institute of Technology
187:himself on August 21, 1945, during a
118:Massachusetts Institute of Technology
554:from the original on August 30, 2015
1691:People from New London, Connecticut
1656:American people of Armenian descent
13:
1706:Deaths by acute radiation syndrome
1686:People from Waterbury, Connecticut
1681:People from Los Alamos, New Mexico
1350:Bombings of Hiroshima and Nagasaki
831:from the original on April 7, 2014
488:
300:'s Critical Assembly Group at the
175:, which designed and produced the
14:
1722:
847:
734:Slosberg, Steven (June 8, 2000).
611:A Review of Criticality Accidents
400:surrounded by neutron-reflecting
284:, from which he graduated with a
1711:20th-century American physicists
1671:Deaths from laboratory accidents
1613:
1601:
1589:
1566:
1565:
766:Hayes, Daniel F. (August 1956).
518:Baumann, Paul (August 6, 1985).
470:. September 19, 1945. p. 11
409:
389:
373:
1646:Accidental deaths in New Mexico
623:Los Alamos National Laboratory
566:
550:. Atomic Heritage Foundation.
540:
482:
464:"Article clipped from The Day"
456:
325:brick would render the system
312:Criticality accident and death
16:American physicist (1921–1945)
1:
776:U.S. Atomic Energy Commission
449:
165:Haroutune Krikor Daghlian Jr.
53:Haroutune Krikor Daghlian Jr.
38:
1510:Oppenheimer security hearing
706:: Two Sixty Press. pp.
661:University of Nebraska Press
625:, pp. 74–75, LA-13638,
7:
1651:American nuclear physicists
694:Miller, Richard L. (1991).
10:
1727:
825:"The Third Core's Revenge"
653:Sullivan, Neil J. (2016).
582:. April 1, 1941. p. 3
1563:
1453:Bismuth phosphate process
1448:Atomic Energy Act of 1946
1435:
1404:
1337:
1126:
995:
909:
900:
421:
214:brick onto a 6.2 kg
132:
113:
103:
93:
74:
48:
30:
23:
1701:Purdue University alumni
1676:Manhattan Project people
827:. Restricted data blog.
234:Early life and education
98:Acute radiation syndrome
1530:S-1 Executive Committee
1478:Einstein–Szilard letter
793:2027/mdp.39015095051879
278:West Lafayette, Indiana
262:New London, Connecticut
220:plutonium–gallium alloy
972:Salt Wells Pilot Plant
619:Los Alamos, New Mexico
240:Waterbury, Connecticut
161:
86:Los Alamos, New Mexico
67:Waterbury, Connecticut
1550:X-10 Graphite Reactor
1505:Nobel Prize laureates
1375:509th Composite Group
356:, from a yield of 10
302:Los Alamos Laboratory
193:Los Alamos Laboratory
147:
1458:British contribution
1360:Operation Peppermint
1355:Operation Crossroads
1214:Maria Goeppert Mayer
772:Oak Ridge, Tennessee
704:The Woodlands, Texas
366:Cedar Grove Cemetery
335:criticality accident
266:Bulkeley High School
208:criticality accident
154:McDonald ranch house
108:Cedar Grove Cemetery
1661:Armenian physicists
1219:George Kistiakowsky
1174:Charles Critchfield
823:Wellerstein, Alex.
380:The two physicists
362:radiation poisoning
286:Bachelor of Science
201:radiation poisoning
94:Cause of death
1620:History of science
1596:Nuclear technology
1284:Henry DeWolf Smyth
1063:Robert Oppenheimer
1018:Priscilla Duffield
663:. pp. 14–16.
183:. He accidentally
179:that were used in
162:
78:September 15, 1945
1577:
1576:
1499:Los Alamos Primer
1488:Interim Committee
1443:African Americans
1395:The Great Artiste
1254:Isidor Isaac Rabi
1249:Norman Ramsey Jr.
1048:Franklin Matthias
987:Heavy water sites
894:Manhattan Project
670:978-1-61234-890-2
354:neutron radiation
318:neutron reflector
306:Manhattan Project
290:Marshall Holloway
282:Purdue University
173:Manhattan Project
160:on July 13, 1945.
142:
141:
122:Purdue University
1718:
1618:
1617:
1616:
1606:
1605:
1594:
1593:
1592:
1585:
1569:
1568:
1520:Quebec Agreement
1304:John von Neumann
1244:George B. Pegram
1053:Dorothy McKibbin
887:
880:
873:
864:
863:
841:
840:
838:
836:
820:
814:
813:
811:
809:
795:
778:. pp. 2–3.
763:
754:
753:
751:
749:
731:
722:
721:
701:
691:
682:
681:
679:
677:
650:
641:
640:
639:
637:
631:
616:
605:
592:
591:
589:
587:
570:
564:
563:
561:
559:
548:"Harry Daghlian"
544:
538:
537:
535:
533:
515:
506:
505:
503:
501:
486:
480:
479:
477:
475:
460:
413:
402:tungsten carbide
393:
377:
322:tungsten carbide
274:particle physics
212:tungsten carbide
81:
62:
60:
43:
40:
35:
21:
20:
1726:
1725:
1721:
1720:
1719:
1717:
1716:
1715:
1626:
1625:
1624:
1614:
1612:
1600:
1590:
1588:
1580:
1578:
1573:
1559:
1525:RaLa Experiment
1431:
1400:
1365:Project Alberta
1333:
1329:Chien-Shiung Wu
1259:James Rainwater
1194:Richard Feynman
1184:John R. Dunning
1159:Norris Bradbury
1122:
1108:Stafford Warren
1078:William Purnell
1058:Kenneth Nichols
1038:Ernest Lawrence
1013:James B. Conant
991:
905:
896:
891:
850:
845:
844:
834:
832:
821:
817:
807:
805:
784:10.2172/4343762
764:
757:
747:
745:
732:
725:
718:
692:
685:
675:
673:
671:
651:
644:
635:
633:
629:
614:
606:
595:
585:
583:
572:
571:
567:
557:
555:
546:
545:
541:
531:
529:
528:. pp. 1, 4
516:
509:
499:
497:
487:
483:
473:
471:
462:
461:
457:
452:
424:
417:
414:
405:
394:
385:
378:
331:prompt critical
314:
256:in what is now
236:
120:
89:
83:
79:
70:
64:
58:
56:
55:
54:
44:
41:
26:
17:
12:
11:
5:
1724:
1714:
1713:
1708:
1703:
1698:
1693:
1688:
1683:
1678:
1673:
1668:
1663:
1658:
1653:
1648:
1643:
1638:
1623:
1622:
1610:
1598:
1575:
1574:
1564:
1561:
1560:
1558:
1557:
1552:
1547:
1542:
1537:
1532:
1527:
1522:
1517:
1512:
1507:
1502:
1495:
1490:
1485:
1480:
1475:
1470:
1468:Chicago Pile-1
1465:
1463:Calutron Girls
1460:
1455:
1450:
1445:
1439:
1437:
1436:Related topics
1433:
1432:
1430:
1429:
1424:
1419:
1414:
1408:
1406:
1402:
1401:
1399:
1398:
1391:
1384:
1377:
1372:
1367:
1362:
1357:
1352:
1347:
1341:
1339:
1335:
1334:
1332:
1331:
1326:
1321:
1316:
1311:
1306:
1301:
1299:Stanisław Ulam
1296:
1291:
1286:
1281:
1276:
1271:
1266:
1261:
1256:
1251:
1246:
1241:
1236:
1234:Edwin McMillan
1231:
1226:
1221:
1216:
1211:
1206:
1201:
1196:
1191:
1186:
1181:
1179:Harry Daghlian
1176:
1171:
1169:John Cockcroft
1166:
1164:James Chadwick
1161:
1156:
1151:
1146:
1141:
1136:
1130:
1128:
1124:
1123:
1121:
1120:
1115:
1110:
1105:
1100:
1095:
1090:
1088:Charles Thomas
1085:
1083:Frank Spedding
1080:
1075:
1070:
1065:
1060:
1055:
1050:
1045:
1043:James Marshall
1040:
1035:
1030:
1025:
1023:Thomas Farrell
1020:
1015:
1010:
1008:Arthur Compton
1005:
999:
997:
996:Administrators
993:
992:
990:
989:
984:
979:
974:
969:
964:
959:
954:
949:
944:
939:
934:
924:
919:
913:
911:
907:
906:
901:
898:
897:
890:
889:
882:
875:
867:
861:
860:
854:Harry Daghlian
849:
848:External links
846:
843:
842:
815:
755:
723:
716:
683:
669:
642:
593:
565:
539:
507:
495:www.theday.com
481:
454:
453:
451:
448:
423:
420:
419:
418:
415:
408:
406:
396:The sphere of
395:
388:
386:
379:
372:
313:
310:
235:
232:
158:the shot tower
140:
139:
134:
130:
129:
115:
111:
110:
105:
101:
100:
95:
91:
90:
84:
82:(aged 24)
76:
72:
71:
65:
52:
50:
46:
45:
36:
28:
27:
25:Harry Daghlian
24:
15:
9:
6:
4:
3:
2:
1723:
1712:
1709:
1707:
1704:
1702:
1699:
1697:
1694:
1692:
1689:
1687:
1684:
1682:
1679:
1677:
1674:
1672:
1669:
1667:
1664:
1662:
1659:
1657:
1654:
1652:
1649:
1647:
1644:
1642:
1639:
1637:
1634:
1633:
1631:
1621:
1611:
1609:
1604:
1599:
1597:
1587:
1586:
1583:
1572:
1562:
1556:
1553:
1551:
1548:
1546:
1543:
1541:
1538:
1536:
1533:
1531:
1528:
1526:
1523:
1521:
1518:
1516:
1513:
1511:
1508:
1506:
1503:
1501:
1500:
1496:
1494:
1491:
1489:
1486:
1484:
1483:Franck Report
1481:
1479:
1476:
1474:
1471:
1469:
1466:
1464:
1461:
1459:
1456:
1454:
1451:
1449:
1446:
1444:
1441:
1440:
1438:
1434:
1428:
1425:
1423:
1420:
1418:
1415:
1413:
1410:
1409:
1407:
1403:
1397:
1396:
1392:
1390:
1389:
1385:
1383:
1382:
1378:
1376:
1373:
1371:
1368:
1366:
1363:
1361:
1358:
1356:
1353:
1351:
1348:
1346:
1345:Alsos Mission
1343:
1342:
1340:
1336:
1330:
1327:
1325:
1322:
1320:
1319:Robert Wilson
1317:
1315:
1314:Eugene Wigner
1312:
1310:
1307:
1305:
1302:
1300:
1297:
1295:
1294:Edward Teller
1292:
1290:
1287:
1285:
1282:
1280:
1277:
1275:
1272:
1270:
1269:Glenn Seaborg
1267:
1265:
1262:
1260:
1257:
1255:
1252:
1250:
1247:
1245:
1242:
1240:
1239:Mark Oliphant
1237:
1235:
1232:
1230:
1229:Willard Libby
1227:
1225:
1222:
1220:
1217:
1215:
1212:
1210:
1207:
1205:
1202:
1200:
1197:
1195:
1192:
1190:
1187:
1185:
1182:
1180:
1177:
1175:
1172:
1170:
1167:
1165:
1162:
1160:
1157:
1155:
1152:
1150:
1147:
1145:
1142:
1140:
1139:Robert Bacher
1137:
1135:
1132:
1131:
1129:
1125:
1119:
1118:Roscoe Wilson
1116:
1114:
1111:
1109:
1106:
1104:
1101:
1099:
1096:
1094:
1091:
1089:
1086:
1084:
1081:
1079:
1076:
1074:
1071:
1069:
1066:
1064:
1061:
1059:
1056:
1054:
1051:
1049:
1046:
1044:
1041:
1039:
1036:
1034:
1033:John Lansdale
1031:
1029:
1028:Leslie Groves
1026:
1024:
1021:
1019:
1016:
1014:
1011:
1009:
1006:
1004:
1003:Vannevar Bush
1001:
1000:
998:
994:
988:
985:
983:
980:
978:
975:
973:
970:
968:
965:
963:
960:
958:
955:
953:
950:
948:
945:
943:
940:
938:
935:
932:
928:
925:
923:
920:
918:
915:
914:
912:
908:
904:
899:
895:
888:
883:
881:
876:
874:
869:
868:
865:
859:
855:
852:
851:
830:
826:
819:
803:
799:
794:
789:
785:
781:
777:
773:
769:
762:
760:
743:
742:
737:
730:
728:
719:
717:0-02-921620-6
713:
709:
705:
700:
699:
690:
688:
672:
666:
662:
658:
657:
649:
647:
628:
624:
620:
613:
612:
604:
602:
600:
598:
581:
580:
575:
569:
553:
549:
543:
527:
526:
521:
514:
512:
496:
492:
489:Howard, Lee.
485:
469:
465:
459:
455:
447:
443:
441:
437:
432:
430:
429:Godiva device
412:
407:
403:
399:
392:
387:
383:
376:
371:
370:
369:
367:
363:
359:
355:
351:
347:
342:
338:
336:
332:
328:
327:supercritical
323:
319:
309:
307:
303:
299:
295:
291:
287:
283:
279:
275:
271:
267:
263:
259:
255:
251:
247:
246:
241:
231:
229:
225:
221:
217:
213:
209:
204:
202:
198:
194:
190:
189:critical mass
186:
182:
178:
174:
170:
166:
159:
155:
151:
146:
138:
135:
131:
127:
123:
119:
116:
112:
109:
106:
104:Resting place
102:
99:
96:
92:
87:
77:
73:
68:
51:
47:
34:
29:
22:
19:
1555:Y-12 Project
1540:Smyth Report
1535:S-50 Project
1497:
1493:K-25 Project
1422:Pumpkin bomb
1393:
1386:
1379:
1309:John Wheeler
1279:Louis Slotin
1274:Emilio Segrè
1224:George Koval
1204:James Franck
1189:Enrico Fermi
1178:
1134:Luis Alvarez
1093:Paul Tibbets
1068:Deak Parsons
858:Find a Grave
833:. Retrieved
818:
806:. Retrieved
746:. Retrieved
744:. p. C1
739:
697:
676:November 30,
674:. Retrieved
655:
634:, retrieved
610:
584:. Retrieved
577:
568:
556:. Retrieved
542:
530:. Retrieved
523:
498:. Retrieved
494:
484:
472:. Retrieved
467:
458:
444:
436:Louis Slotin
433:
425:
382:Louis Slotin
343:
339:
315:
280:, campus of
243:
237:
228:Louis Slotin
205:
181:World War II
177:atomic bombs
164:
163:
80:(1945-09-15)
18:
1641:1945 deaths
1636:1921 births
1370:Silverplate
1324:Leona Woods
1289:Leo Szilard
1264:Bruno Rossi
1209:Klaus Fuchs
1113:Ed Westcott
1103:Harold Urey
659:. Lincoln:
298:Otto Frisch
63:May 4, 1921
42: 1944
1630:Categories
1473:Demon core
1417:Little Boy
1338:Operations
1154:Niels Bohr
1144:Hans Bethe
1127:Scientists
1073:Boris Pash
952:Los Alamos
804:. TID-5360
770:(Report).
748:August 15,
708:68, 69, 77
586:August 15,
558:August 15,
532:August 15,
450:References
440:demon core
348:(5.1
294:cyclotrons
224:demon core
197:New Mexico
185:irradiated
133:Occupation
59:1921-05-04
1696:Plutonium
1515:Plutonium
1381:Enola Gay
1199:Val Fitch
1149:Aage Bohr
1098:Bud Uanna
967:Oak Ridge
808:August 8,
636:April 21,
398:plutonium
292:with the
254:Gaziantep
216:bomb core
171:with the
169:physicist
137:Physicist
114:Education
37:Daghlian
1571:Category
1427:Thin Man
1388:Bockscar
982:Wendover
962:New York
957:Montreal
947:Inyokern
922:Berkeley
903:Timeline
835:April 4,
829:Archived
627:archived
552:Archived
358:fissions
250:Armenian
218:made of
1608:Physics
1582:Portals
1545:Uranium
1412:Fat Man
1405:Weapons
977:Trinity
942:Hanford
927:Chicago
802:4343762
741:The Day
579:The Day
525:The Day
500:July 1,
474:July 1,
468:The Day
304:of the
937:Dayton
931:Site A
800:
714:
667:
422:Legacy
258:Turkey
150:tamper
88:, U.S.
69:, U.S.
910:Sites
630:(PDF)
615:(PDF)
352:) of
252:from
917:Ames
837:2014
810:2015
798:OSTI
750:2015
712:ISBN
678:2021
665:ISBN
638:2010
588:2015
560:2015
534:2015
502:2024
476:2024
75:Died
49:Born
856:at
788:hdl
780:doi
346:rem
245:née
195:in
156:to
1632::
796:.
786:.
774::
758:^
738:.
726:^
710:.
702:.
686:^
645:^
621::
617:,
596:^
576:.
522:.
510:^
493:.
466:.
431:.
368:.
350:Sv
337:.
308:.
230:.
203:.
126:BS
39:c.
1584::
933:)
929:(
886:e
879:t
872:v
839:.
812:.
790::
782::
752:.
720:.
680:.
590:.
562:.
536:.
504:.
478:.
128:)
124:(
61:)
57:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
_with_assembled_tamper_plug_containing_the_plutonium_pit_and_initiator_for_transport_to_the_shot_tower_on_13_July_1945._LA-Loading_components_(34823045643)_(cropped).jpg){kind=spacer}