SC28 Monitoring System

Manufacturer

Spicer Consulting

Spicer Consulting has built a world-wide reputation in magnetic field cancelling for electron microscopes and similar instruments. Today, working with equipment manufacturers and users alike, the company is recognised as an industry expert in maximising the performance of electron microscopes, electron beam lithography systems, CD-SEM and focused ion beam tools. Spicer Consulting magnetic field cancelling systems protect sensitive equipment in the world's leading laboratories, universities and semiconductor manufacturing plants, as well as in the test facilities of electron and ion beam equipment manufacturers. Its magnetic field, vibration and acoustic analysis systems have been adopted as standard equipment for the conduct of site surveys by leading equipment manufacturers.

Key Features

Long term monitoring of the room environment for electron beam instruments, including Scanning Electron Microscopes (SEM), Transmission Electron Microscopes (TEM) , Electron Beam Lithography tools and SEM-based metrology and inspection tools
Continuously measures Magnetic fields in 3 axes, Floor vibration in 3 axes and Acoustic levels all at 2kHz, and Temperature/humidity at 1Hz
Inputs for 1 x 3-axis magnetic field sensor, 3 x Wilcoxon 731A accelerometers, Brüel & Kjær precision microphone, Temperature/Humidity sensor, and one BNC AUX
Up to 14 different graphs may be displayed giving simultaneous display of the data as it is acquired
Acquires sensor data and logs spectra and charts to date-stamped files
Headless - Can run without user interface open
Compares environment to specifications with PASS/FAIL indication. Sends signal to a traffic light or sends email if offline or out-of-spec

Overview

The SC28 monitoring system is purposed-designed to monitor the environment for electron beam instruments, including Scanning Electron Microscopes (SEM), Transmission Electron Microscopes (TEM), Electron Beam Lithography tools and SEM-based metrology and inspection tools. It can log the spectrum and charts of ambient magnetic fields, vibrations, acoustic levels, temperature and relative humidity. It measures the magnetic fields, vibrations and acoustic levels at a sample frequency of 2 kHz and temperature/humidity at 1Hz. Measurements are taken continuously, with no gaps, so that no event is missed. The SC28 software runs on a Windows PC that is connected to the same Local Area Network as the SC28/SI. It automatically detects the SC28/SI hardware without needing to know its IP address in advance. The SCplot program is included with the SC28 software and allows you to view and print results as well as save graphs for use in reports.

SC28/SI-Sensor Interface (Ethernet-based)

The Sensor Interface operates from universal AC power (100-240 V ~ 50/60 Hz) which is used to power all the sensors and its embedded Analog Devices Blackfin microcomputer. For long term monitoring applications, where loss of data would not be acceptable, the sensor interface can be powered from an un-interruptible power supply. Our tests with a fully charged 350W UPS from APT provided up to four hours of operation. There are inputs for two Spicer Consulting 3-axis magnetic field sensors. There are inputs for three Wilcoxon 731A accelerometers. The inputs provide the constant current load and power supply for each Wilcoxon 731A and are suitable for most other types of piezo accelerometers when using the spectrum program. There is an input for a Brüel & Kjær 4190/2669L precision microphone. The Interface provides the special power supplies for the 2669L microphone pre-amplifier to enable the microphone to operate to its full specification. There is a general purpose DC coupled auxiliary input via a BNC connector at the back of the interface.

A multi-channel 13 bit ADC controlled by an embedded Analog Devices Blackfin Microcomputer acquires all the signals in digital format inside the Interface. The microcomputer performs extensive signal pre-processing before the signals are sent to the laptop computer through the USB connection.

Sensor SC24/DC+AC

This is the 3-axis magnetic field sensor supplied with the SC28 monitoring system. It can measure DC and AC fields, e.g. changing DC fields from trams and elevators and AC power line fields. It has internal bias coils that are used to null the Earth’s field. The bias coil currents are reset by clicking an icon on the program screen when the sensor is moved. The measurement range is ± 20 mG. The sensor has low noise and is accurate to within 1% when completely warmed up.

Wilcoxon Research model 731A accelerometer

The Wilcoxon Research model 731A has a measurement range of 200 mg's Pk-Pk and a bandwidth of 0.1 Hz to 500 Hz when used with the SC28 monitoring system. It can be used to measure extremely low level vibrations. Its noise limit is 0.03μg/ √Hz at 2Hz. The system supports simultaneous measurements by three accelerometers. Each accelerometer measures along one independent axis. With three correctly oriented accelerometers, vibration can be measured in three orthogonal axes.

Brüel & Kjær 4190/2669L microphone

The Brüel & Kjær 4190 microphone with 2669L preamplifier connects directly to the sensor interface. It provides acoustic measurements to acoustic laboratory reference standards. It measures sound levels from 20dB to 110dB and 1.5Hz to 500Hz when used with the SC28 monitoring system. It measures infrasound levels (i.e. frequencies below 20Hz) which can limit the performance of transmission electron microscopes by vibrating the sample.

Sensor SC28/TH

This is a combined temperature and relative humidity sensor supplied with the SC28 monitoring system, with a temperature accuracy of ±0.2 °C and humidity accuracy of ±2 %RH.

Product range

SC11 Compact Analysis System
SC11 Sensor Interface Analysis System
SC11 Auto Survey System
SC28 Monitoring System

Software

SC28 Monitor Software

While data logging, the SC28 software runs as a small window that shows the current status of logging, whether the environment is within specification and the number or emails sent. The software uses very little CPU in this state. The SC28 Monitor window is provided for setting up the sensors, analysis, logging, environmental specifications and email parameters. When everything is configured, you can close this window and data logging will continue in the background. The SC28 provides 10 channels of data acquisition. In the SC28 Monitor, these signals can be displayed on 6 scales and in 3 display formats (Scope, Spectrum and Chart). Up to 14 different graphs can be viewed at the same time, allowing you to see the data as it is collected.

Spectrum Analyser Controls

The Spectrum controls set the Frequency Range, Number of points in the spectrum, the Window function, the Spectrum Mode and the Combine Mode. The Spectrum Analyser uses a Discrete Fourier Transform (DFT) algorithm to calculate the spectra of captured waveforms. You can apply a Window function to the waveforms of all channels before the DFT is calculated. The following windows are available: None, Hanning or Flat top.

Chart Recorder Controls

The Chart controls set the size and unit of the Time Step for the chart and the Lower and Upper bandwidths for each signal. The following time steps between chart points are available. Setting this is a compromise between the time resolution and the size of the data files produced.

Data Logging Controls

The SC28 provides two types of data logging files Chart and Spectrum. Each have their own folder, file name and file inter- val settings. In addition, the SC28 can automatically delete old log files to save disc space. File names can embed date and time information so that they are unique and can show the time period that they cover. Start and Finish refer to the start and finish times of the data in the file. All date and time information, including the time zone, is derived from the PC running the SC28 program.

Environmental Specifications

You can use the Specifications feature to check whether the site meets the environmental specifications of an electron beam instrument or other equipment. You can load in multiple specification files to show on the Spectrum and Chart displays for direct comparison with the measured results. A specification editor is included so that you can create specifications for the chart recorder or the spectrum analyser. Chart specifications have a minimum and maximum value. Spectrum specifications are piece-wise linear graphs of maximum amplitude versus frequency.

Email

The Email panel controls how and when emails are sent by the SC28 Monitor. Emails are only sent if Enable Email is ticked. You enter the details of your email server, user id and password similar to setting up an email client. The SC28 can then send emails whenever the environment goes out of specification, or if the SC28/SI goes off line for any reason. You can limit the number of emails sent. The emails include a single line for each event, giving the serial number of the SC28, the date time and type of event.

SCplot

SCplot is a comprehensive results editing program that enables results logged from the SC28 Monitor to be formatted for viewing or adding to reports. It can stitch together multiple chart data logging files to make a continuous plot. SCplot can handle large amounts of data. For example the plot below shows a weeks worth of magnetic field data. The data was extracted from nearly 70 Mbytes of data in 335 files each containing 30 minutes logging at one point per second of 3- axis magnetic field, 3-axis vibration, acoustics, temperature and humidity.

Downloads

SC28 Monitoring System Brochure

If you would like to learn more about Site Survey Systems, contact our experienced technical team today. We would be happy to help you find the right solution for your needs. Contact us today!