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Material World
Element · Cm

Curium

An intensely radioactive metal that has analysed the soil of Mars.

Radiation source

Curium is made in reactors and is fiercely radioactive — enough that it glows from its own decay. That heat has made it a candidate for compact power sources, but its more distinctive use is analytical.

Curium's alpha emission is the excitation source in the alpha particle X-ray spectrometers carried by Mars rovers. Hold the instrument against a rock, and the spectrum of X-rays that come back gives the rock's elemental composition — with no power-hungry X-ray tube.

Uses

Alpha particle X-ray spectrometry on planetary missions is curium's signature application: a small sealed source, no moving parts, and a direct reading of what a rock is made of.

It is otherwise a research material and an intermediate on the way to heavier elements, produced by prolonged neutron irradiation of plutonium.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is a source for

is sourced from

is produced by

  • Neutron irradiation — process · another step up again, and the point at which yields start falling away sharply

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • PubChem
    US National Library of Medicine · Mixed — aggregated third-party content, rights retained by depositors

Questions this page answers

Where it comes from, and what it becomes

Follow Curium back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Curium → is sourced from → Plutonium → is produced by (from uranium-238 absorbing a neutron and decaying twice — produced in every power reactor whether or not anybody wants it, and recovered only by reprocessing spent fuel) → Neutron irradiation → takes as input (uranium-238 is the feedstock for everything heavier: it absorbs neutrons without fissioning, which is what starts the sequence) → Uranium → is produced by (as yellowcake rather than metal: leaching and solvent extraction end at a uranium oxide concentrate, and the metal is several conversion steps further on) → Solvent extraction and electrowinning → takes as input (in the low-grade and oxidised ores that flotation cannot economically treat, with bacteria oxidising the sulfide into a form the acid can attack) → Chalcopyrite
  • Curium → is produced by (another step up again, and the point at which yields start falling away sharply) → Neutron irradiation → takes as input (uranium-238 is the feedstock for everything heavier: it absorbs neutrons without fissioning, which is what starts the sequence) → Uranium → is produced by (as yellowcake rather than metal: leaching and solvent extraction end at a uranium oxide concentrate, and the metal is several conversion steps further on) → Solvent extraction and electrowinning → takes as input (in the low-grade and oxidised ores that flotation cannot economically treat, with bacteria oxidising the sulfide into a form the acid can attack) → Chalcopyrite
  • Curium → is sourced from → Plutonium → is sourced from (formed from uranium-238 in a reactor and recovered from spent fuel) → Uranium → is produced by (as yellowcake rather than metal: leaching and solvent extraction end at a uranium oxide concentrate, and the metal is several conversion steps further on) → Solvent extraction and electrowinning → takes as input (in the low-grade and oxidised ores that flotation cannot economically treat, with bacteria oxidising the sulfide into a form the acid can attack) → Chalcopyrite
  • Curium → is sourced from → Plutonium → is sourced from (formed from uranium-238 in a reactor and recovered from spent fuel) → Uranium → is extracted from (the principal uranium ore, and the pitchblende the Curies worked) → Uraninite
  • Curium → is produced by (another step up again, and the point at which yields start falling away sharply) → Neutron irradiation → takes as input (uranium-238 is the feedstock for everything heavier: it absorbs neutrons without fissioning, which is what starts the sequence) → Uranium → is extracted from (the principal uranium ore, and the pitchblende the Curies worked) → Uraninite
  • Curium → is sourced from → Plutonium → is sourced from (formed from uranium-238 in a reactor and recovered from spent fuel) → Uranium → is produced by (as yellowcake rather than metal: leaching and solvent extraction end at a uranium oxide concentrate, and the metal is several conversion steps further on) → Solvent extraction and electrowinning → takes as input (a carbonate dissolves straight into acid, which is why an oxidised orebody goes to a leach pad and the sulfide beneath it goes to a smelter) → Malachite

These are the most distinct paths back. Curium can be traced through others besides.

Downstream — what it becomes