demon core
E719940
The demon core was a subcritical mass of plutonium used in early U.S. nuclear weapon experiments at Los Alamos, infamous for causing two fatal criticality accidents in 1945 and 1946.
All labels observed (1)
| Label | Occurrences |
|---|---|
| demon core canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T8246492 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: demon core Context triple: [demon core, hasAlternativeName, demon core]
-
A.
Demons
"Demons" is a track by British electronic musician Fatboy Slim, featured on his 2000 album "Halfway Between the Gutter and the Stars."
-
B.
Demons
"Demons" is a popular, introspective pop-rock song by Imagine Dragons that explores inner struggles and personal darkness.
-
C.
Demons
The Demons are the nickname of the Melbourne Football Club, one of the oldest and most storied teams in Australian rules football.
-
D.
Demons
"Demons" is a drill-rap track by Fivio Foreign that helped establish his presence in the New York drill scene with its dark production and aggressive delivery.
-
E.
Demons
Demons is a political and psychological novel by Fyodor Dostoevsky that explores radicalism, moral chaos, and the destructive consequences of nihilist ideology in 19th-century Russia.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: demon core Target entity description: The demon core was a subcritical mass of plutonium used in early U.S. nuclear weapon experiments at Los Alamos, infamous for causing two fatal criticality accidents in 1945 and 1946.
-
A.
Demons
"Demons" is a track by British electronic musician Fatboy Slim, featured on his 2000 album "Halfway Between the Gutter and the Stars."
-
B.
Demons
"Demons" is a popular, introspective pop-rock song by Imagine Dragons that explores inner struggles and personal darkness.
-
C.
Demons
The Demons are the nickname of the Melbourne Football Club, one of the oldest and most storied teams in Australian rules football.
-
D.
Demons
Demons is a political and psychological novel by Fyodor Dostoevsky that explores radicalism, moral chaos, and the destructive consequences of nihilist ideology in 19th-century Russia.
-
E.
Demons
"Demons" is a drill-rap track by Fivio Foreign that helped establish his presence in the New York drill scene with its dark production and aggressive delivery.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
nuclear experiment component
ⓘ
plutonium core ⓘ subcritical mass ⓘ |
| accidentType | prompt criticality accident ⓘ |
| associatedLaboratory | Los Alamos National Laboratory NERFINISHED ⓘ |
| associatedWithProject | early U.S. nuclear weapons program ⓘ |
| causedDeathOf |
Harry Daghlian
NERFINISHED
ⓘ
Louis Slotin NERFINISHED ⓘ |
| compositionDetail | plutonium-gallium alloy ⓘ |
| countryOfOrigin |
United States of America
ⓘ
surface form:
United States
|
| criticalityAccident |
Harry Daghlian accident
ⓘ
Louis Slotin accident ⓘ |
| dateOfAccident |
21 August 1945
ⓘ
21 May 1946 ⓘ |
| era |
World War II
ⓘ
early Cold War ⓘ |
| givenName | demon core ⓘ |
| hasMass | approximately 6.2 kilograms ⓘ |
| isPartOf | Manhattan Project NERFINISHED ⓘ |
| legacy | symbol of dangers of nuclear research ⓘ |
| locatedIn | Los Alamos, New Mexico NERFINISHED ⓘ |
| material | plutonium ⓘ |
| nickname | Rufus NERFINISHED ⓘ |
| notableFor |
causing two fatal criticality accidents
ⓘ
laboratory criticality safety lessons ⓘ |
| originalIntendedUse |
core for a third nuclear weapon
ⓘ
weapon core for planned strike on Japan ⓘ |
| placeOfUse | Los Alamos Laboratory NERFINISHED ⓘ |
| plutoniumIsotope | plutonium-239 ⓘ |
| radiationType |
gamma radiation
ⓘ
neutron radiation ⓘ |
| relatedConcept |
critical mass
ⓘ
criticality accident ⓘ nuclear chain reaction ⓘ |
| relatedPerson |
Enrico Fermi
NERFINISHED
ⓘ
Harry Daghlian NERFINISHED ⓘ Louis Slotin NERFINISHED ⓘ |
| safetyIssue |
lack of remote handling equipment
ⓘ
manual manipulation of neutron reflectors ⓘ |
| safetyLesson |
ended hands-on criticality experiments at Los Alamos
ⓘ
led to stricter criticality safety procedures ⓘ |
| shape | sphere ⓘ |
| startUseDate | 1945 ⓘ |
| statusAfterAccidents |
melted down
ⓘ
recycled into other cores ⓘ |
| usedFor |
criticality experiments
ⓘ
nuclear weapon experiments ⓘ |
| weaponDesignContext | implosion-type nuclear weapon ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: demon core Description of subject: The demon core was a subcritical mass of plutonium used in early U.S. nuclear weapon experiments at Los Alamos, infamous for causing two fatal criticality accidents in 1945 and 1946.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
demon core