 |
||||||||
 |
||||||||
 |
 |
 |
 |
 |
 |
 |
||
|
|||||||||||||||||||||||
|
Colloquia 2005 Towards NMR at 100 Tesla in Pulsed High Field MagnetsProfessor
Juergen Haase Date 4-5 p.m., Monday, 14 February, 2005 Location School of Physics
Common Room Outline Nuclear
Magnetic Resonance (NMR) methods continue to spread in research and
industry with the biggest expansion occurring in medical imaging. Nearly
all NMR experiments benefit from strong, static, homogeneous magnetic
fields that boost sensitivity and resolution. In addition, field driven
effects can only be studied at high enough fields as fascinating examples
in the field of strongly correlated electrons show. In the past, superconducting
magnet technology was able to raise the field strength steadily. Now,
with no superconducting materials in sight that can sustain more than
some 22 Tesla, various laboratories revert to resistive (Bitter-type)
magnets to be able to raise the field to 33 T. Very few even employ
hybrids of non-persistent superconducting and resistive magnets that
consume tremendous amounts of energy to achieve 45 T. A further increase
in field strength for NMR seems illusory. Outside NMR, already P. Kapitza
showed that the highest magnetic fields can most easily be achieved
by using pulsed currents and small coils without cooling where the coil
can heat up adiabatically during the field pulse. Indeed, such pulsed
magnets are increasingly being employed for measuring properties such
as magneto-resisitance, magnetization and susceptibility. It was believed
and it seemed proven that NMR can not be performed in such pulsed magnets.
Here we will demonstrate that this is not true with the first NMR experiments
at up to 60 T and beyond 2 GHz in such magnets. With specially adapted
NMR techniques these magnets are not as hostile as ones thought. While
this opens the possibility of performing NMR at unprecedented fields
and frequencies we believe that pulsed magnets may also provide the
basis for another expansion of NMR into areas where the use of supreconducting
magnets was out of question. The audience, including graduate students, are invited to meet the speaker 15 minutes beforehand over wine and cheese in the Physics Common Room. Further InformationContact
|
|||||||||||||||||||||
