rd  - 1962 - ENC Conference

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SLAVE RECORDER FOR AN ~4R SPECTP.OIdETER
James N. Shoolery, Varian Associates, Palo Alto, California, and
Richard W. Mattoon, Abbott Laboratories= North Chicago, Illinois
Presented at the Third Conference on Experimental Aspects of NMR Spectro-
scopy, Mellon Institute, Pittsburgh, Pennsyivanias March 2 and 3, 1962
~t is often very useful to have a slave recording reduced in size from
the master NMR spectrum and available simultaneously with it. This
eliminates the delay in cb=aining a reproduction of the master spectrum.
Also, a good slave recording on standard 8 I/2" x II 'I paper is conveni-
ent as a secondary record for reports and for an auxiliary research
file. The master spectrum for the Model A-60 ~[R spectrometer measures
ll" x 26" overall with the graduated chart space 25 cm. Y-axls, 50 + 2 cm.
X-axis (9.8" x 20.~').
METHOD I,L SLAVE X-AX~S TIME SWEEP
In ldethod I. a Moseley X-Y recorder, Model 3S, using 8 II~' x II" graph
paper (graduated in inches in Figure I only by chance) was covmected
to the A-60. The two AHP/INT OUTPUT terminals on the rear of the A-60
console were connected to the two Y-axls input terminals of the slave
recorder. The Y-axis gains were set to give appropriate amplitudes.
Each recorder was cet for its own internal 500-second full X-axis
sweep. The A-60 was adjusted to put the SiMs 4 line on the right-hand
0 of its X-axis (chemical shift). Since this slave recorder time-
sweeps only to the right, both recorders were set on the extreme left
and started simultaneously.
Figure i shows that the slave recording is a practically perfect repro-
ductlon of the masker recording even for the small background ripples.
The strong peak at 60 CPS (I,0 PPI0 is a doublet at highest resolution
(evident here as a slight shoulder) and this is reproduced in the
slave recording. The slave recorder reached its right-hand limit a
little before the A-60 and so on the slave recording the SIMs 4 line is
to the right of the edge of the graduated portion of the paper. X-dls-
placements in Figure I between corresponding peaks on the master to
those on the slave give a ratio varying between 1.89 and 1.93, averaging
1.91. The disadvantages of Method I. are the inability (I) to sweep
to the leftp (2) to independently set the SIMel. line exactly on the 0
of the slave and keep the two recorders so-syn~hronlzed,o,- and (3) to
have the ratio of the two X-axes 2,00 exactly.