Because timing is everything

TempoSTEM: Event Responsive Imaging

Trigger-event modulated probability observation, or Tempo for short, is a new paradigm in low-dose STEM imaging.

By combining Tempo with a beam blanking system like the Electrostatic Dose Modulator from IDES Inc., the user can dynamically modulate the number of electrons delivered per pixel in real-time as you collect data from the sample. Once enough electrons have been counted to accurately characterise a pixel, the blanking system prevents excess damage from further beam exposure. In this way, the Tempo hardware unit enables a new ‘event responsive’ imaging approach.

You set the count – prevent sample damage with low counts while exploring, then increase your count rate to improve contrast and accuracy while maintaining control over the total dose delivered to your sample.

Rate or Wait?

Typical STEM imaging accumulates electrons scattered across different detectors by waiting for a fixed exposure time per pixel. TempoSTEM imaging does the inverse: measuring the time needed for a set number of electron events, and outputting the rate of electrons hitting the detector.

Get the most from your electrons. Maximum information efficiency is achieved by measuring exactly what you need, with no unnecessary beam exposure.

Pulse And More

Tempo is an expanded successor to our Pulse electron counting system. That means as well as programmable TempoSTEM controls you get the same benefits of real-time plug-and-play digital electron counting in one system.

Why Tempo?

– Flexibly balance dose and precision

– Maximum information efficiency extracted from a minimum delivered electron dose

– Compatible with existing STEM detectors

– Gain all the advantages of Pulse and more!

Frequently Asked Questions

Similar to a Pulse unit, the Tempo unit is connected to the analog outputs of the TEM’s detectors. This is most easily done by T-ing into the BNC connectors between these detectors and the acquisition unit (e.g. Digiscan). Two additional digital BNC outputs from the Pulse unit send a trigger signal in response to a programmable count threshold – these are connected to the external trigger control of your blanking unit.

Tempo, like Pulse, will be available in 2 and 4 channel versions. The 2 channel version has 2 analog inputs with 2 digital count outputs. The 4 channel version has 4 analog inputs and 4 digital outputs. Both versions have 2 Tempo outputs to control the blanking system.

This means that the operator can collect, for example, HAADF and MAADF images with the 2 channel version.***

The digital signals are transmitted using an industry-standard TTL digital line. This means that the Tempo unit is compatible with any acquisition system that is capable of recording digital ‘ones’. Tempo is compatible with the Gatan Digiscan 2* and Point Electronic ‘DISS6’ acquisition systems. The Pulse unit will also be forward compatible with any counting image acquisition system such as the Gatan DigiScan 3*. * DigiScan is a trademark of Gatan Inc.