The Use of Digital Delay Generators in Laser Induced Breakdown Spectroscopy Applications

1. The Use of Digital Delay Generators in Laser Induced Breakdown Spectroscopy Applications

2. Digital Delay Generator • Digital Delay Generator - a key component for LIBS applications • Precise timing between the laser and detector • Sets the duration of the detector gate • Sets the time between lasers – dual pulse • Determine the rate and number of pulses – multiple pulse Timing is a variable in every LIBS application and proper timing can greatly enhance the efficacy of a system.

3. Digital Delay Generator – What Does It Do?

4. Digital Delay Generator – What Does It Do? It provides several different sets of timing pulses – each synchronized to one another

5. DDG Features • The pulses: • Trigger and synchronize lasers • Delay and gate ICCDs • Delay and gate cameras and imaging equipment

6. LIBS Applications • The dynamics of the laser plume/plasma in LIBS determines the optimal time to take measurements • The vapor plume expands after the laser, then • Two shockwaves – in the background gas region and in the vapor plume occur, then • From a few µS to tens of µS, the plume experiences radiative heat loss. • Dynamic changes occur with time • Bottom line – wavelength, type of sample, laser energy, laser width, your detector configuration – all affect the optimal time to take a measurement

7. LIBS Applications • One needs to adjust delays and gates to find the optimal settings – this is what a delay generator gives you

8. The Role of the Delay Generator • Dual pulse methods have improved the limits of detection for many LIBS applications • Orthogonal and collinear methods have been discussed in the literature • Differing energy levels for each laser is indicated • In all cases the time between lasers is adjusted for optimal results

9. Multi-pulse LIBS • Multiple pulses from one laser or firing of several lasers • Low energy multiple pulses via a DDG burst • Sequencing several lasers with a single detector via a multi-channel DDG

10. Berkeley Nucleonics Corporation • BNC makes inexpensive delay generators that • Delay and gate ICCDs • Control the time between dual pulses and then delay and gate the ICCD • Provide single triggers to multiple lasers • Provide multiple triggers to a single laser • BNC has been making digital delay generators since 1973