SPIN
ECHO
In t h e past ten years steady-state ( C W ) nuclear m a g n e t i c resonance ( N M R ) h a s g r o w n from a p h e n o m e n o n of largely academic interest into one of the most important of analytical research tools. The thorough exploitation of steady-state techniques during a period when the equally important and complementary transient or "SPIN ECHO"®phenomena were being largely ignored can be ascribed to the commercial development and ready availability of commercial C W spectrometer systems. Harvey-Wells has n o w developed© the Series ELH, SPIN E C H O Systems which for the first time make available to research workers the full range of applications of N M R . T h e design philosophy of this series involves the concept of basic building blocks which permit the efficient realization of complete systems of various degrees of complexity and sophistication, together with full interconvertibility as the g r o w t h of the user's needs may dictate. For detailed specifications and price scheduling or for discussion of applications to your research needs, please contact Harvey-Wells Corporation, Framingham, Mass. or call (617) 872-4365. Multiple exposure of p r o t o n echoes following a 90°-18O° p u l s e s e q u e n c e of variable spacing in a dilute aqueous solution of C u S 0 4 . T h e exponential decay of the e c h o amplitudes corresponds t o a transverse relaxation time T 2 of 2.9 msec. This relaxation results from m a g netic dipole interaction between the water protons and the electronic spin of the hydrated C u + + ion.
(?)
I·. L. Hahn, Phys. Rev. «0,580 (1950).
(2)
under exclusive license to U. S. Parent No. 2,887,67^.
@
Carr & Purcell, Phys. Rev. 88,-115 (1952).
Single exposure of a CarrPurcell sequence(3)of a single 90° pulse followed by a long train of 180° pulses separated by 320 Msec in distilled water. The observed pattern is the super-imposition of 30,000 echoes occurring midway between the 180° pulses. Time constant of the decay gives a relaxation time T.. of 2.1 sec. Similar experiments can be used to measure diffusion constants
Circle No. 173 on Readers' Service Card
VOL.
6,
O. 6, MAY 1964
·
7 A
The new RIDL Nanolyzer* is an im portant advance in multi-channel pulse height analyzer design. It has removed the instrumentation limits, imposed by presently available analyzers, on new areas of investigation in high energy physics, fast radio-chemistry and like applications. The principal advantage of the Nano lyzer is its ability to collect and handle more data per unit time with an un precedented degree of accuracy. It ac cepts, analyzes, stores and displays data seven to fifty times faster than conventional analyzers. Central to this ability is the utilization of a 100 mega cycle ADC providing a 10 nano second /
channel address rate, Snap-Logic sili con elements and a thin-film memory plane. In addition to the obvious advantage of high speed data acquisition for appli cations where high counting rates or very short counting times are en countered, the Nanolyzer effects im portant economies of time and cost in less demanding uses. Its data handling speed permits more efficient use of accelerator facilities, and results in more accurate data. Important and unique features of the Nanolyzer follow: THIN-FILM MEMORY: Memory
cycle
time of 0.6 μ sec. does not contribute to system dead time because of parallel data transfer from ADC. Capacity 105 or 106 counts for each of the 256 channels. ANALOG TO DIGITAL CONVERTER: 100 megacycle crystal controlled, syn chronized ramp start/stop, zero cross over timed amplitude analysis, differ ential linearity of 2%, dynamic range 376 channels with digitally selected zero suppression of up to 120 channels without pulse distortion. INPUT CIRCUITS: Double delay-line shaped pulses for rapid system re covery. Selective analysis only of pulses satisfying following criteria: delayed c o i n c i d e n c e / a nti-co i n c i d e n c e g a t e
THE NEW RIDL NANOLYZER OPENS NEW AREAS OF INVESTIGATION THROUGH TOTALLY NEW LIMITS OF INSTRUMENTATION CAPABILITY LONG TERM RELIABILITY—The Nanolyzer is modular in design and construction. It uses printed circuit boards with functional logic groups on separate boards (illustrated below on left). The computer circuits use all-silicon transistor Snap-Logic elements to assure matched circuit components during servicing and replacement (illustrated below on right).
8 A
·
ANALYTICAL CHEMISTRY
timed thru internal ANTI-WALK® Discriminator, unique pile-up rejection circuit, and upper /lower discriminators. Built-in four-channel mixer for one, two or four data inputs in~:o one, two or four sub-groups without external logic, OPERATING MODES: Six electronically interlocked push switches control all input/output functions. Add or subtract from PHA storage. Remote operating capability. Automatic preset livetime or clock-time, or preset count operation in any selected channel. Entire memory or any selected part useable during data storage or display. Region-O-lnterest* control for selective readout of entire memory, halves,
quadrants or between digitally selected upper and lower channel limits. Readouts through magnetic tape, parallel printers, punch tape, IBM typewriter and live external display.
Nanolyzer is one of the most significant advancements in multichannel analyzer technology in recent years. Please write for literatu I*C. NUC:R-4-224 ^Trademark of RIDL
CONSTRUCTION: Modular construction, plug-in printed circuit boards, allsilicon transistor Snap-Logic* elements. Solid state throughout, functional and simple to use controls. Would you like to know more about this remarkable Nanolyzer? We will be happy to send you more information and complete specifications. After critical evaluation, we believe that you will agree that the development of the
RIDL RADIATION INSTRUMENT DEVELOPMENT LABORATORY A DIVISION OF NUCLËAH-CHICAGO
CORPORATION
4501 West North Ave., Melrose Park, Illinois 60160 Phone: 312 681-2323, Cable: RADILAB
Circle No. 10 on Readers' Service Card
VOL 36, NO. 6, MAY 1964
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9 A
