A quantum dot ensemble of an embodiment of the present disclosure includes a plurality of quantum dots (120) each including a core (121) including a compound semiconductor and a shell layer (122) including one or more organic ligands (122A) coordinated to a surface of the core (121) and an oxide film (122B) that covers a portion of the surface of the core (121) to which the one or more organic ligands (122A) are not coordinated, and adjacent quantum dots of the plurality of quantum dots (120) are adjacent through the one or more organic ligands (122A) or the oxide film (122B).

Disclosed is a header for a radiation detector assembly provided for mounting a detector head into an enclosure formed by the header and a detector can to form the radiation detector assembly. The detector head includes a semiconductor radiation detector arranged on a first side of a substrate and a thermoelectric cooler, TEC, arranged on a second side of the substrate, the header including: a base plate having a first side for mounting the TEC and a second side with an attachment mechanism for attaching the radiation detector assembly to a radiation-detecting appliance; contact pins that provide electrical coupling through the base plate protruding from the first side of the base plate to substantially define a rim for accommodating the TEC within the rim; and a draining outlet with an opening through the base plate between its first and second sides transferring a gas to and/or from the enclosure.