Dynamic Nuclear Polarization of Irradiated Target Materials.
Polarized nucleon targets used in high energy physics experiments usually employ the method of dynamic nuclear polarization (DNP) to polarize the protons or deuterons in an alcohol. DNP requires the presence of paramagnetic centers, which are customarily provided by a chemical dopant. These chemically doped targets have a relatively low polarizable nucleon content and suffer from loss of polarization when subjected to high doses of ionizing radiation. If the paramagnetic centers formed when the target is irradiated can be used in the DNP process, it becomes possible to produce targets using materials which have a relatively high polarizable nucleon content, but which are not easily doped by chemical means. Furthermore, the polarization of such targets may be much more radiation resistant. We have irradiated and studied dynamic nuclear polarization in ammonia, deuterated ammonia, ammonium hydroxide, methylamine, borane ammonia, butonal, ethane and lithium borohydride. These studies were conducted at the Stanford Linear Accelerator Center using the Yale-SLAC polarized target system. Our results indicate that the use of ammonia and deuterated ammonia as polarized target materials would make significant increases in polarized target performance possible.
- Pub Date:
- Physics: Elementary Particles and High Energy