Case Study

Application

Materials Science -Big Physics

ProductDN6.221-12 Digitizer
12 Channel 1.25 GS/s 8 Bit

Solid State Materials Science using High Magnetic Fields
Introduction
The International MegaGauss Science Laboratory is part of theInstitute Solid State Physics (ISSP) at the University of Tokyo.
The objective of the laboratory is to study the physical properties
of solid-state materials (such as semiconductors, magneticmaterials, metals, insulators, superconducting materials) as they
are subjected to ultra-high magnetic fields. The fields are also used for researching new materials
and controlling their phase and functionality. The laboratories pulse magnets can currently
generate up to 87 Tesla (T) by non-destructive methods, and from 100 T up to 760 T (currently theworld record for the strongest field generated in-doors) by a destructive process.

The Requirement
As part of a major push to optimize the magnetic fields
generated by the laboratories MegaGauss machine it isimportant to synchronize the trigger events that fire banksof large capacitors (figure 1). Ideally, the capacitors allneed to be triggered within 10 ns of each other. As such,the laboratory must examine the trigger signals for eachcapacitor to determine their key characteristics and timing
relationships. The MegaGauss machine also requires
careful control as physical parameters restrict its firing tojust a few shots per day.
In order to capture and analyze the trigger signals ISSP
required a fully synchronous 10 channel digitizer systemthat delivers a single shot sampling rate in excess of 1
gigasamples per second (GS/s). The high sampling rate
allows the shape and frequency content of individual
trigger pulses to be revealed, while fully synchronous
sampling ensures inter-channel timing measurements canbe consistently made with sub-nanosecond precision.

Figure 1. Shows the large capacitor banks that are used toA further complication is the fact that the Megaguass generate the ultra-high magnetic fields of themachine generates dangerously high magnetic fields that MegaGauss machine.
are potentially unsafe and can easily interfere with themeasuring instrumentation. Great care needs to be taken to shield both equipment and operators.
The measurement system needs to be located in the laboratory while the operator adjusts andmonitors the experiments from the safety of a control room (figures 2 and 3). As such, the digitizer
system must be able to operate remotely and controlled over the laboratories network.

© Spectrum GmbH, Germany

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Figure 2. The digitizerNETBOX is located close to the large capacitors and housed in a shielded enclosure to
avoid EMI. LXI control allows easy operation with a Notebook PC or via a connection to the laboratory
network.

Figure 3. The MegaGauss machine is safely operated from the main control room.

© Spectrum GmbH, Germany

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The solution
The solution from Spectrum was the DN6.221-12
digitizerNETBOX system. This unit met all the necessary
technical requirements offering 12 fully synchronouschannels,eachsamplingat
1.25
GS/s. As
digitizerNETBOX units are LXI compliant instruments they
allow full remote control and data transfer over a Gbit
Ethernet connection. The units also come with SBench 6Pro software which allows the user to quickly setup thesystem and start making measurements. SBench 6-Profeatures an easy-to-use, graphical user interface thatallows multi-channel waveform display, data analysis anddocumentation. Acquired and analyzed signals can be
stored and exported to other devices, or other software
programs, in a number of formats such as MATLAB,ASCII, binary and wave (figure 4). The digitizerNETBOX
systems offer significant advantages over other digitizers
as they provide a turn-key solution to multi-channel
acquisition. Users can select the desired number ofdigitizer channels as well as fundamental specifications
such as the sampling rate, resolution and on-board Figure 4. An acquisition showing 10 independent trigger
signals (used to fire the capacitors) but captured
acquisition memory.

Conclusion

synchronously by the DN6-221-12 digitzerNETBOX.
Signal characteristics are easily identified and criticaltiming measurements can be made. Data is also exported
for further analysis and documentation.

The Spectrum digitizerNETBOX provides an easy-to-use
multi-channel data acquisition system that is well matched to the requirements of ISSP. Thesystem was quickly installed and integrated into the MegaGauss machine so that trigger timing
measurements and analysis could be made with improved precision and detail. The laboratory is
now able to further optimize the performance of the Megagauss machine with the expectation thatthey will be able to generate the worlds highest ever in-door magnetic fields later in 2017.

Article written in collaboration with the International MegaGauss Science Laboratory, Institute Solid State
Physics (ISSP) at the University of Tokyo© Spectrum GmbH, Germany

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