A spin echo method adapted to the measurement of long nuclear relaxation times (T2) in liquids is described. The pulse sequence is identical to the one proposed by Carr and Purcell, but the rf of the successive pulses is coherent, and a phase shift of 90° is introduced in the first pulse. Very long T2 values can be measured without appreciable effect of diffusion.

1.
F.
Bloch
,
Phys. Rev.
70
,
460
(
1946
).
2.
H. C.
Torrey
,
Phys. Rev.
76
,
1059
(
1949
).
3.
R.
Gabillard
,
Compt. rend.
233
,
39
(
1951
).
4.
J. S.
Gooden
,
Nature
165
,
1014
(
1950
).
5.
E. E.
Salpeter
,
Proc. Phys. Soc. (London)
A63
,
337
(
1950
).
6.
Strick
,
Bradford
,
Clay
, and
Craft
,
Phys. Rev.
84
,
363
(
1951
).
7.
E. L.
Hahn
,
Phys. Rev.
80
,
580
(
1950
).
8.
H. Y.
Carr
and
E. M.
Purcell
,
Phys. Rev.
94
,
630
(
1954
).
9.
Rabi
,
Ramsey
, and
Schwinger
,
Revs. Modern Phys.
26
,
167
(
1954
).
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