Good morning fellow Aalto researchers I am Ilkka Laine Today I will explain you what is Laser-Induced Breakdown Spectroscopy Imaging. My goal here is to explain it clearly enough so everyone will understand what LIBS Imaging is is and how to do it. These slides are available on the internet on libsimaging.net slash researchbreakfast2024, except for some confidential images.

Here is an outline of what I will talk about. So first is context about my background. Second I'll show you two different LIBS imaging devices, LIBS scanners that we have built here in Aalto Department of Civil Engineering, in our laserlab downstairs here and I will show you a bunch of LIBS images made with these devices. This is the main content of my presentation. Then we briefly go through methods for LIBS analysis. And lastly I mention some LIBS resources and information I want to share. First about me for context.

I'm an automation engineer turned LIBS Imaging researcher. I was recruited to professor Jussi Leveinen's team to build LIBS scanners back in 2018. Currently my research goal is to give people the tools needed to do LIBS Imaging analysis and explaining it as simply as possible. I want to make a"LIBS Imaging for dummies".

I believe the fundamentals are most important and many of you don't know what I'm talking about. So What is LIBS? LIBS stands for Laser-Induced Breakdown Spectroscopy. But I find its old name, Laser Spark Spectroscopy is much better name when explaining it to someone. In Laser Spark Spectroscopy we shoot laser to do a spark on the sample and then collect the light of the spark to a spectrometer. The wavelengths of the light reveal all elements and some molecules present in the sample. Imaging means doing many measurements over an area for pretty pictures. With "Many" I mean ten thousand, hundred thousand or millions of measurements. LIBS has been done since laser was invented in the 60s, but LIBS imaging has become prominent and practical only recently. So what's the trick? The trick is doing it fast, cheap, reliably and being capable of measuring any shape samples. So combining cheap, small and fast lasers and spectrometers with the computers controlled scanning movement such as CNC machine or 3D-printer frame, we get a LIBS scanner. Next we look at two LIBS scanners we have built at Aalto. First the LIBS-LIDAR

I believe the fundamentals are most important and many of you don't know what I'm talking about. So What is LIBS? LIBS stands for Laser-Induced Breakdown Spectroscopy. But I find its old name, Laser Spark Spectroscopy is much better name when explaining it to someone. In Laser Spark Spectroscopy we shoot laser to do a spark on the sample and then collect the light of the spark to a spectrometer. The wavelengths of the light reveal all elements and some molecules present in the sample. Imaging means doing many measurements over an area for pretty pictures. With "Many" I mean ten thousand, hundred thousand or millions of measurements . LIBS has been done since laser was invented in the 60s, but LIBS imaging has become prominent and practical only recently. So what's the trick? The trick is doing it fast, cheap, reliably and being capable of measuring any shape samples. So combining cheap, small and fast lasers and spectrometers with the computers controlled scanning movement such as CNC machine or 3D-printer frame, we get a LIBS scanner. Next we look at two LIBS scanners we have built at Aalto. First the LIBS-LIDAR

In Laser Spark Spectroscopy we shoot laser to do a spark on the sample and then collect the light of the spark to a spectrometer. The wavelengths so the colors of the light reveal all the elements present in the sample. Imaging means doing many measurements over an area for pretty pictures. With "Many" I mean ten thousand, hundred thousand or millions of measurements. LIBS has been done since laser was invented in the 60s, but LIBS imaging has become prominent only recently. So what's the trick? The trick is doing it fast, cheap, reliably and being capable of measuring any shape samples. So combining cheap, small and fast lasers and spectrometers with the computers controlled scanning movement such as CNC machine or 3D-printer frame, we get a LIBS scanner. Next we look at two LIBS scanners we have built at Aalto. First the LIBS-LIDAR

LIBS-LIDAR A few years ago back in 2018 was when I was recruited to Aalto University to build a LIBS-LIDAR, a remote LIBS scanner that can map rock walls and tunnel endings from a safe distance with LIBS. This is similar than CHEMCAM LIBS instrument which was built for the Curiosity Mars rovers. Our idea was to bring this technology back to earth. So we built this device that shoots lasers, rotates both directions has adaptive focusing and collecting optics and takes LIBS from a few meters distance to map surfaces like this red image here is this whole tunnel ending mapped. We field tested this device in the Otaniemi tunnels underneath us and demonstrated it properly in mine conditions Kittilä gold mine. But this device is dangerous, heavy and expensive so it was left as a prototype, for now. During this project my collegue started to work on another LIBS scanner device, a drill core scanner. Which I show you next and that turned out be the jackpot so to say.

This is our main tool. Large Area Scanning Open-source Laser-Induced Breakdown Spectrometer or LASOLIBS. It was designed to scan drill cores one box at at time but can be used to scan any shape samples that fit in the device. We work mainly with geological samples so that means rocks mostly. I will show a little video if that works. The device is this 3-axis frame similar to 3D printers that moves the LIBS measurement head over the sample. It has autofocus to make consistent sparks on any shape samples and can do up to thousand measurements per second and move the measurement head half a meter per second. Drill cores are these cylindrical pieces of rock extracted from the ground with a diamond drill and they are super important for any mining or ore-exploration projects to figure out what's in the ground. As a side note, the original plan for this design was to publish the building instructions as free and open hardware for anyone to build this by themselves. I have published them partially and am still working on that but so far the instructions are not finished, as my research colleague and the main guy behind this device Lasse Kangas left to start a company Lumo Analytics in Helsinki that does these commercially and so successfully that he doesnt have any extra time. A commercial version of LASOLIBS by Lumo Analytics is used in multiple mine and ore exploration sites in Finland, USA and Australia and soon elsewhere. So the business side of this is doing great.

 Building this device was a fun time with experimental lab work. A little invention we made while building this device is our autofocus method which is a cheap an simple method. We have a position sensitive detector PSD set behind Pros: cheap and easy to build

## LIBS Images 1: Drill cores Here's some results, so that's a couple of elemental intensity maps, Iron, Sulphur and Nickel, all important to find the ore in this case. And on the right are examples of mineral classification made with LASOLIBS so each color here means a different mineral or material.

## LIBS Images high resolution HIGHRES LIBS images This is a scan from a piece of drillcore so a small piece of rock, about 4 x 5 centimeter area. On the left is calcium and on the right is potassium. So our device can do both large areas quickly or small areas in very high detail. Scanning a box takes depending on the wanted resolution from minutes to couple hours.

## LIBS Images high resolution

## LIBS Images: Hand sample We're not limited to drill cores but any shape sample. Here's just a rock thrown in the scan.

LIBS Images. Then I want to show you some of my favourites. These are result of 16 pieces of drill core, each of these a separate sample collected in this image. The pieces were about 4centimeter wide and 6 to 20centimeter long.

A single element. They are so beautiful. And you can zoom in quite a bit in this

Three elements in one picture, Red is lithium, green is potassium, blue is silica.

Magnesium Aluminiun Sodium in the same manner Next: How are these results made from the measurement data.

LIBS Analysis Methodology Simply. Methodology simple enough you can do it with pen and paper and a book of the peaks

Spectral Angle Mapper(SAM) is an essential

US National Institute of Standards and Technology Atomic Spectral Database

Thanks! And qustions please

+358 50 581 6319 (Lumo CEO Antti Kotanen)

Thanks! And qustions please

previous draft versions: edellinen: I work at Aalto Civil Engineering department building Laser-Induced Breakdown Spectroscopy(LIBS) scanners and developing LIBS imaging with mining industry. I came to Nordic LIBS 2024 to share with you what we can do with this technology. To present the very basics of LIBS imaging to give you a clear image of what it is. Cons: need to keep libs laser on to autofocus. ## LIBS Imaging Devices ### LASOLIBS Autofocus system Autofocus using position sensitive detector(PSD) with LIBS laser as light source.