T(ingdom and the United States have declared that they would not for the tine being deploy nuclear weapons with sma1l yields in such a way as to blur the nuclear threshold. 80" The development of nuclear veapons continues at a very active pace. Recently. emphasis has been put not only on the manufacbure of warheads rrithdjflerent yields, but also on changing other veapon charact erist ic s . The propoz'tion of energy ihat is derived from fission and. fusion, respectively, can bevaried vithin large linits" By surround.ing a weapon vith casings of various kinds,the radiatlon properties may be changed. I'Ihi1e initial radiation vi11 generalll. decrease r,rith increasing mass of the weapon casing, residual radiation can beeither increased or decreased. Ul,. The most widely discussed example is the sc-cal,led "neutron bomb'r, referredto as an I'enhanced rad.iationrr (ER) weapon in official United States sources"A/35/392 English Annex Page 37 The neutron bomb" which is a reratively old concept, voultt be arrangeal so that afarge amount of its explosive energy comes from the fusion of aleuteriur withtritirm. While this reaction gives rise to more ener€ietic neutrons than afission chain reaction, the d-esign of the weapon rouLd be such as to nininize theconversion of neut"on energy into bl-ast and heat. por a bypothetical l-kt. XRr,teapon, the zone of danger due to neutrons would. considerably exceed that due toblast. This has been d.escribed as an advantage vhen the weapon is enployedagainst s.rf,oured forces, as anmoured vehicl-es are quite resistant to blast analheat but offer littl-e shielding against neutrons. Consequentl"y, these veapons
**Analysis**
The text appears to be discussing the development and characteristics of nuclear weapons, specifically the concept of "neutron bombs" and their potential effects on armored vehicles. The language used is technical and focused on the physical properties of the weapons, suggesting that the topic is primarily related to science and technology.

**Category**
Science and Technology