Materials

Various conditions are set for the target materials used, which should ensure their use in the context of a scattering experiment:

• high dilution factor (ratio of polarizable nuclei to total number)
• a high degree of polarization
• a short setup time of the polarization
• a long relaxation time of the polarization
• a good resistance of the polarization to radiation damage
• easy handling and production

For the DNP, the materials must be additionally provided with free paramagnetic centers. There are two methods for this:

• chemical doping by admixture of certain radicals, such as TEMPO
• radiation damage caused by an intense electron beam

Established materials are butanol, ammonia and lithium hydride, as well as their deuterated counterparts. While butanol can be doped chemically, this is not readily possible with ammonia and lithium hydride, since these are gaseous or solid under standard conditions.