Spectrometer Control Computer

The JNM-ECZ spectrometer control computer（SCC) is a high performance computer with large capacity hard disc, and is used for execution of pulse sequences, signal-to-noise calculation during measurement, storage of data, data processing, etc. are all possible and independent of the workstation.
All measured data is written to the SCC hard disc without fail, thus the SCC also serves as a data server.
Even if there is any kind of failure to the workstation computer or network during sequential measurements, all measurements that were submitted will be executed normally and the results will be written to the SCC’s disc.
Even in a multi-user environment where many users require different measurements and processing, stable operation of the instrument is assured.

Multi-Sequencer

The sequencer controls RF, lock and PFG channels during pulse sequence execution. The JNM-ECZR spectrometer can use multiple slave sequencers which control each of these channels, and a master sequencer which synchronizes all slave sequencers. Individual slave sequencers can execute pulse sequences irrespective of synchronous or asynchronous. Thus, by controlling several slave sequencers by the master sequencer, any NMR pulse sequence can be carried out.
Hence, the JNM-ECZR spectrometer can accommodate up to 8 nuclei, 32 frequency sources and PFG simultaneously. It can compile and execute any complex pulse sequence, even those that may be developed in the future.

STS (Smart Transceiver System)

The Smart Transceiver System (STS) is a highly advanced integration of RF sequencer, DDS (Direct Digital Synthesizer), FSU (Frequency Synthesizer Unit), transmitter, receiver, acquisition unit and gate control unit into a single transceiver board. This is equivalent to integrating the basic composition of an NMR system onto one board.
The standard instrument composition is one source with 2 nuclei, 8 frequencies and one receiver.
The JNM-ECZR spectrometer can accommodate up to four RF transceiver boards, and so can support 8 nuclei, 32 frequencies and 4 receivers.

Highly Precise Digital Control

The STS used in the JNM-ECZR spectrometer realizes control at the highest speed for frequency, phase and amplitude modulation, with a control time resolution of just 5ns. This high speed digital control is extremely useful for high speed phase modulation pulses which are required for the most recent NMR pulse sequences. The same time control performance is offered for various external systems.

High Performance DDS

The DDS (Direct Digital Synthesizer) unit of the JNM-ECZ spectrometer available from the STS, can create a very wide offset range.
Using an appropriate probe, this enables a “pseudo 3 nucleus” measurement with the standard instrument. For example, ¹³C{¹H}{¹⁹F} measurement is possible with the standard configuration of JNM-ECZ spectrometers.

Receiver

The receiver of the JNM-ECZ spectrometer is controlled by the sequencer. A reference frequency generated in the receiver can be dynamically modulated for phase and amplitude even during FID sampling.
DQD (Digital Quadrature Detection) by high speed A/D conversion at 16 bit 100 Msps, not only improves the effective dynamic range for quantized noise, but also reduces unwanted signals such as IMD, by over-sampling at high rates.
In addition, the digital receiver filter optimized for NMR ensures accurate quantitative results.
The high dynamic range of the JNM-ECZ spectrometer enables the observation of very small signals. The ¹³C satellite signals of acetone in a mixed sample of H₂O:DMSO:Acetone=18570:104:1 (approx.10 % D₂O) are clearly observed (approx.1/3400000).

Multi-sequencer and Multi-dimensional NMR measurement

The JNM-ECZR spectrometer can control up to four RF sources, thus 8 nuclei and 32 frequencies, using the multisequencer method, with each RF source controlling 2 nuclei and 8 frequencies. Intelligent control of multiple RF sources enables not only highly precise execution of complex multi-dimensional NMR measurements, but allows the use of parallel expressions within the pulse sequence. In addition, by using conditional statements within a pulse sequence, more than one experiment is possible using the same pulse sequence program.

Digital NMR Lock Circuit

Application of STS technology provides high precision and high speed digital control of the 2H lock. This new digital feedback circuit offers extremely efficient control of the magnetic field against external modulation.
The precise digital lock feedback mechanism thus enables highly stable operation for protracted measurements.

Shimming

The gradient shim capability of the JNM-ECZ series is not limited to observation of deuterium (²H) as is normally used, but also other nuclei such as ¹H or ¹⁹F. Such functionality is useful for “No-D NMR™” and can also be used for measurement of solids.

What is gradient shimming?

This is a high speed shimming method that measures the magnetic field distribution (magnetic field map) of the sample, compares it to a standard map then calculates and applies the required shim values for correction so that the magnetic field map becomes uniform.

Spectrum before and after resolution adjustment by gradient shimming. At 49 sec. resolution has improved.

No-D NMR measurement using resolution adjustment by selective pulse gradient shimming where the solvent has multiple signals (top). Solvent signal is automatically suppressed by the ‘WET’ method (bottom).

Resolution adjustment is possible by gradient shimming in the same manner as ²H, by selecting the ¹⁹F signal.

Temperature Control System

The temperature control system enables stable measurements using a newly-designed heater with improved response. The JNM-ECZ spectrometer allows faster and more stable operation of peripheral devices using the new high speed bus control line.

Head Amplifier Chassis

The head amplifier chassis has various functions related to probe and the super conducting magnet. A touch-panel display is located on top of the head amplifier chassis, offering an intuitive user interface. During probe tuning, reflection dip and reflection value are indicated, whilst during cryogen refilling, the actual level of cryogen in the magnet is indicated in real time. It makes the routine maintenance related to probes and super conducting magnet convenient and efficient.

Head Amplifier Chassis

Indication of reflection dip when probe tuning

Indication of remaining quantity when refilling Helium