 Welcome to the second talk in the series. Like my first talk, this will be of a tutorial nature. And as Anurag already mentioned, this will be an introduction into what can you do at home with tabletop spectroscopy? How do you write a propelling, or a very compelling beam time proposal? And how do you work on making the resources we have used in the most efficient way? I will show a little less active science, but more really as a tutorial part. But maybe let's start first with myself. And I originally studied in Jena in Germany on thin film technology, growing thin films, analyzing them. Then I went to Immuno, did some surface spectroscopy, came to Lund in 2006, so it's now 14 years, and started to build tabletop spectrometers and started to ultra-fast time resource spectroscopy. Then I went for a postdoc to NIST in Colorado in US, again continuing with tabletop spectroscopy, a postdoc in Krenovle, the ESAF Synchrotron facility, as a visiting scientist, beam line scientist, and then came back to Lund, continuing with tabletop spectroscopy, time resource spectroscopy, and now really mostly working on time-resolved parts. In this talk today, I really would like to introduce you what can you do in tabletop setups, and why should you use them? So as a motivation, I will not really go into the science, which I have done in my last talk, but as a motivation, I will tell you what are actually the limitations of large-scale facilities, if you want to use large-scale facilities. For me, as a scientist, there are three major limitations. Which I like to try to address with tabletop approaches. One is the time it takes for doing experiments, or before I can do an experiment. So I have to prepare the proposal, the beam time, which is a part. I have to assemble a team, particularly for time-resolved experiments. This can be more than 10 people. So I need to collaborate with other groups. I need to find collaborations. I need to, after data collection, I need to analyze a large amount of data, which takes multiple many years of work to really get through those ones. And most important, it's the time it takes before I can do my experiments. So waiting time from the announcement of the call when I prepare my proposal until I have done my beam time and have my data, not until it's analyzed, but until I get my data. It's typically from half a year up to a year. And this was all before COVID-19. Now I got quite a few of my own beam times canceled. So this time extends. So this is obviously one time where I can really speed up with having something in the lab. Second, it's the risk and the efforts I need to put into a proposal. I need to write the proposal. And I will motivate why this is actually quite some work. This can be up to a week for a good time-resolved proposal. For a steady state, it's not quite as much. I have to prepare the beam time. And if I write the proposal, I also risk, because it's a peer view, I risk that these ideas are actually out, so the hottest ideas is a bit challenging. Second, prepare to see efforts in preparation. For example, for timers of proposals, I need to prepare samples for about one week of beam time or multiple days. This can be one gram of a very rare molecule. And if I, like in my case, work on rare organometallic complexes, we produce roughly 20 milligrams per week per person. That means there's a significant effort to actually produce enough samples for beam time. Now, the difference at a large-scale facility is that usually I need to have enough sample for the whole beam time. So I need to guess how good is my sample. Do I have sample? Do I have damage? So I need to have enough sample for the whole beam time. In the lab, I can run the small batches, try it, and test it again. Next, there is no guarantee of success of a proposal. If your proposal is good, of course, you have a good rate. And I have an excellent track record. But if the proposal, you cannot guarantee it. So if you apply for grants, that's a risk factor that you need to account for. Lastly, it's the costs. Now, these are poor guesses taken from the budgets. And I'm very well aware that this can be off by a factor of two or three. But still, a time-resolved experiment, for example, at Nixville, costs for my personal group is if I have to finance 10 people for one week in the US, that's about 40,000 euros. The facility costs are even higher. This is taken from the budget. And one can estimate roughly 2 to 3 million euros for a beam time. For a beam time, the normal shrinkage one is not quite as much. For my own group, it's four people for one week, so not too much. But the facility is still a significant amount of money. Now, this is not really too scary. You don't have to pay this. This is paid by the taxpayer. But the importance of it is that your proposal needs to reflect this. So your proposal needs to be good enough to really, for us as a society, to finance this proposal. And this puts a real limitation on the science you can actually do. That means the science I'm proposing for the beam time, there has to be a success. I have to estimate that this beam time will be successful. So this will be not the most risky experiments I do, but this will be experiments which are somewhere in between in the balance. Typically, as I said, that you do some part is risky, some part is not risky. But it really doesn't push me to the edge of the science. And this is where really the lab-based equipment can come and help. Because with the lab-based equipment, I can rule out quite a lot of the risks. I can do pre-experiments. I can study the most burning experiments at home. And then write a really propelling proposal for the large-scale facilities, and go much better prepared to the facilities and make this investment really worth it. So that's why we're going to look into time, into lab-based equipments and lab-based setups today. Let's look back. What interactions do we have? That's a spec for my last talk. And today, I really want to focus on the spectroscopy. So the incoming photons are absorbed and I probe the density of empty states, the skeins or xas, and I probe the density of filled states with XES. For this, I send in light of very, very wavelengths. And you're going to see that there is a difference between beam times or beam line, or large-scale facility experiments, and lab-based experiments. The major difference is really on the sources you're using. Because the sources where you have bendy magnets, undulators and wigglers, or even resonant for fields, those ones, there are very few setups where you could do this in your lab. But typically what you have is you have an X-ray tube, where you have an acceleration of an electron with a voltage, which is then stopped at the material. So we're going to focus today on X-ray tubes. X-ray tubes produce two types of radiation. One is, of course, the characteristic radiation, which is really a particular to the element. The second one is the very broad radiation. What is nice, the radiation is proportional to the numbers of electrons you're sending in, and it is proportional to the element you're using for stopping the electrons. The real limitation is actually the melting, or is the heat, because you're actually putting a significant amount of current in a very small region. Small region is important, for example, if you do imaging, because the spot size is your resolution. Again, from my last talk, the bigger the spot size, the more blurry the resolution, and this is predominant for both the imaging, but also for spectroscopy. So the numbers of photons you can put in the small, or the numbers of electrons you can put on a very small spot size is limited, which means that the flux you can actually get out of an X-ray tube, or a tube source like this, is limited. Now, these are numbers I've taken from a paper, which I'm gonna cite in a second, but this is roughly the integrated flux, the integrated flux in the line, but also the integrated flux over the whole broadband radiation. Those sources can be big, but they can also be small. This is the source I'm using most often in my lab, both 15 centimeters. They can be fairly handy. The challenge with it is that this flux is, if it's in the line, it's perfect for imaging. If you do spectroscopy with it, it is distributed over a very wide range. Now, in comparison to underlighters, or large facilities, there the flux is in a very narrow range. That means the photons per second, per millimeter, per opening angle, or per divergence, and per energy is significantly higher for underlighters. But this means that you have to be in a more clever design, how you design your experiments. Now, this number we're gonna come back to in a second. So the question is, how do you use those photons, which you can generate with a lab-based equipment? Now, those sources are steady state. I come from a time-resolved field, so I built myself a time-resolved source working in the same principle. For me, I use a laser, focus it on a water jet, produce an electric field, accelerate electrons, get the same kind of broad brainstorm spectrum with very similar numbers of photons, no, this is per percent bandwidth. If you put this per EV, this is roughly the same. So we have the same order of magnitude, and we have a small little setup. So the clue or the key of using those type of setups is the detection. Now, there are three different types of detectors in general, and we're gonna go through each of those. Number one, I want to go to our energy disperser detectors. Energy disperser detectors take the photon energy, absorb the photon, produce one fast electron, and then you can do a lot of different things with the electron. Classically, in an ion chamber, for example, you can shoot those photons into a gas, you produce your ions and your electrons, and then you can accelerate them. The first, if you put two little voltage for the acceleration, then we combine, nothing happens. The next range, you get a proportional, you extract all the electrons you have or the charges you have, one by one. So one photon, one electron. In the next range, you can magnify this to a certain intensity. Typically, that's just a magnification factor of below 200, which you then read out. And if you have a Geiger counter, where you do the typical click per photon. So in those ranges, what you do is you count photons, you count how many photons are coming. There's a second way how we can use dive detection. Is the single photon, the single ion or electron you're producing is high energetic. So afterwards, there's a cascade. When the electron is moving through the material, it can produce further electrons. Can indeed produce a whole bunch of electrons. Typically about 2000 electrons in silicon for 6KV photon. Now there's a nice paper where this is produced. You can do this in a silicon drifted diet and extract, for example, 2000 electrons for one photon. A different energy of the photon would produce a different number. And the height of the signal getting out of here is an indication or as a number for how much energy did the photon have. Now in the CCD, for example, if you would use a CCD, it works in a very similar way. You have a depth, a zone where it's a depletion. The charge is generated to generate a charge cloud. You can transfer this into a transfer channel or into the transfer channel. And from there on, you can read it out for each pixel. As you can see here, each pixel is now its own diet or its own detector. If you analyze the numbers of electrons or the signal you're getting out of there, you can get a spectrum, which is limited by the numbers of electrons, by the statistics behind of it. And this is a fairly nice spectrum. The advantage of it is that you have a very broad range. You have a huge area of a detector, which is really close to your source. It's very high quantum efficiency. It's relatively cheap. And you can practically, for example, collect up to 10% of all photons emitted from a source if you look, for example, for XAS. You can count how many photons do you have. You can retrieve the energy of a single photon and then do a statistics, make a spectrum from there. You might have to model the details. And for pulse sources, you can use an every detector like a CCD. My thesis actually summarizes a lot of those parts, quite interestingly. The challenge, however, is that this cascade in what you produce the signal from which you get this wide bandwidth, which is really nice and linear, is limited by how many particles do you produce. In silicon, for example, this is about 2,000 electrons for 6KV photon because of the band gap of silicon. Now, to overcome this limitation because these numbers of electrons limit the resolution you can get. And as they have shown in the previous slide, the resolution is about 100 DV. So this is fully sufficient to do XAF, to analyze how many materials you have. And very nice to have actually in the lab. It's also very nice to analyze the spectrum of your source. That's my source spectrum as a broadband, but it's not really enough to make high-resolution science. For this, was a new development, which is the cryogenic X-ray detection. For example, there's a whole bunch of different detectors. I'm quite active in this field. There's four different kinds I will focus on too. In one, for example, you generate a tunneling junction where you have a superconductor, an insulator, and a superconductor. Photons coming in produce again your bunch of electrons. The electrons that are now generated in this insulator can tunnel through this insulator bandgap. And from the numbers of electrons which can tunnel through here, again, you can extract the photon energy. The key is that this generation is now significantly limited or your bandgap is limited is not 1.1 DV, but typically of the order of a few tens of milli-electron volts, meaning that you get significantly more particles per photon, better statistics, better resolution. The second family is the thermal family where you absorb a photon, half a tiny piece of metal. The piece of metal heats up. You measure the temperature of this metal. This is actually for mega-electron volts. How this literally looks like. This is your absorber. Your temperature is down here. You can make an area of these parts. Now, instead of having looking on the charge, which is a faction, you convert this charge into heat and measure the heat of the total photons. What you measure then is for each photon arriving as a rise in the fall of the temperature. That's the measurement, not the simulation for different photon energies. From the integral below here, you can extract what was the photon energy. And from this, you can build the statistic. The thermometer you're using needs to be, of course, very sensitive. It needs to measure one millikelvin temperature changes. We use superconducting to normal conductive transition for this approach. And by using this one, you can achieve fairly high energy resolution. And not why this one is made for MEVs, typically for normal X-rays. This is done in the thin film technology. So you can actually grow this as a whole area. The challenge is this. It's the typical operational temperature of such devices as 80 millikelvins, absolute. Means that if this is my detector, I need to shield it one, two, three times, and then put the vacuum jacket around it to actually be able to operate it in the lab. This can be done. That's the photo of my lab. That's my detector. That's my X-ray source, my plasma source. And that's my interaction range, my lab setup. Nice. You can use this type of detection, this type of spectroscopy, the same detector or the same kind of detector used for this is soft X-ray energies from the 400 EV range. This is what I call tender sulfur emission, for example, which is in the two and a half KEV range. This is hard X-ray emission down in the seven kilo electron range. And this is X-ray absorption spectroscopy. Now down time resolved, come probe done in the lab with this plasma source or with such as plasma source taken with a micro-calorometer. The advantage of this compared to detector before is very efficient. This is the total numbers of photons emitted from my source detected. So this is of the range of one percent or slightly below but half a percent range. Why this is still very, very good. It gonna come to the other technology now in a minute. So we have energy dispersive detectors which are very sensitive, typical of the silicon drift or CCDs or germanium type. We have resolutions of about 100 EV at six KEV which is enough for X to F, but not enough for really high science. We have cryogenic detectors which are very efficient in detection, have high resolution, are rather expensive as I come back in the second. Now the third group is the one which is most likely to be used in the lab for high resolution spectroscopy which would be wavelengths dispersive spectrometers. The challenge is set by an optical spectroscopy. If you would use a classical grating you would expect to have reflectivity of about 50% in total. And this means not just the one wavelengths which you really focus on but all wavelengths are reflected and you can collect them. In crystals or in X-ray signs there is a difference. The difference is that the angle of total reflection for optical light for example if this is metal is nearly 100% as reflected for X-rays. And now if you look for example on let's say this curve gold one degree this is the reflectivity of a surface and this reflectivity is breaking in as soon as you really come into the X-ray range. With other words if you wanted to build such a grating for X-rays you would need to do this with incoming angles of 0.5 degrees of an area which is significant, very big, very large and then the layer proportion or the quality you would need to make this grating of is single atomic layers over a very large range. It has been tried but it's not something which is typically available. The way around it is to use crystals with reflectivity. Again we have discussed this already in my previous talk that there are certain angles for each wavelength one angle where you come in and you have a very high reflectivity or very high diffraction. The interesting thing is that for if you come in with one energy this angle in which this one is reflected is very, very narrow. And the difference in contrast to the grating is that all other wavelengths which come at exactly the same angle are not reflected in different direction but are absorbed. It means the efficiency of such a grating is very interesting. If you look for example on a flat crystal take a source, one geometry and assume a typical reflectivity now assuming that there is crystal stress and the different, not absolute perfect crystal but as close as possible to perfect then we get in reflectivity checking just the angle of acceptance of something of 10 to the minus seven. That means that this is the energy which is reflected. Now, there are ways around it. One way around it for example to use cylindrical band crystals in so-called von Hammers geometry where we use an cylindrical band crystal where each band of this part is now again in black condition and is refocusing the light onto its spot. So one wavelength is actually diffracted from a bigger area. This is significantly increasing the efficiency. This approach is nowadays used in most large-scale facilities. This is a photo from the LCLS in Stamford where we use 16 of those cylindrical band crystals. This is from Sakla in Japan. Here's six cylindrical band crystals. They are roughly of the order of three centimeters times 10 centimeters sometimes a bit bigger, sometimes a bit smaller. Now the advantages that you have for each wavelength a zone which is reflective and you can reflect many wavelengths at the same time. So in one dimension, they are focused in the second dimension, this is dispersive. A second geometry which you can use to amplify or increase your efficiency is cylindrical. So not cylindrical, it's a spherical band crystal where you refocus one point onto another point using slits, for example, to control and shield. The challenges that you need to move now this crystal for each wavelengths, we need to scan it. That means we have to have motor control. Again, that's the efficiency is significantly increased because now you have a big area which is reflecting. You come something of the order of 10 to the minus four. Again, in certain facilities, this is from the ESAF, big areas of crystals are made and many of those crystals are combined. There are even commercial instruments available for the lab where for example, one of those crystals is put in a geometry. This motor movements of the scanning of the rockings is provided and the Jerry Seidler, for example, has commercial product or provides a commercial product and this YouTube movie, for example, is from a separate seminar series. It shows a little bit what you can do with this in the lab. Now, how does this all link to lab-based spectroscopy? Well, the point is that if you want to do lab-based spectroscopy, you need to collect a certain numbers of photons in a certain band range and depending on your problem, the numbers are different. Now let's go through the numbers. For steady state saints, you need something of the order of 10 to the six photons in-house spectrum, which you need to collect. For XAS, something of the order of 10 to the five photons, three times 10 to the five. These plots and bars here are for different concentrations and really made for pump probes, so for time-resolved spectra, for steady state, it's a little bit better, but this are the typical numbers you would need for a steady state. I need to point out that this is done or calculations are done for very high concentrations. So this is done for 100 millimole. Now, how does this link? Well, our source produce something of the order of 10 to the five photons per second. If you look on the numbers for what crystal, for example, synodic crystal can produce or can transmit, this gives you a count rate of something of 100 photons per second. Syracuse band crystal, something of 80 photons per second. For XAS, applying all of those numbers, you get something of the order of 10 to the six from the source. And you can collect 30 photons per seconds or 10 photons per second from such a setup. With a micro-calorometer, it's superconducting. We have a constant part of 5000. That means combining the two, you need roughly three hours in the lab, one to three hours for a high concentration sample to do XAS or an XAS spectrum. Sounds like a long time, but again, you can do this at any time. You can collect as long as you want. And if you design the spectrum properly, you can actually do fairly a lot of signs with such a setup. Now, again, there's number two, three, four, five factor, which is depending on the precise geometry and everything around it, but this is doable. Price, well, sources about three to five, three to 20 kilowatts, a crystal, doesn't matter which of the two is of the order of seven. The detectors is the one of the 20. So you can build such a setup for not too much money or you can buy ready devices of about 100 kilo euros. If I compare to the numbers we actually needed for the proposal, for running a large scale facility, this is comparable to one beam time, two beam times running in your own lab. That's an interesting point. Of course, there's a limitation. The flux is significantly less. So you have to work with high concentration samples, but as preparation for the beam time, definitely a good option. Now let's go. Let's say you have done all the pre-work. You have an interesting piece of science. You want to write a beam time proposal. For an effective beam time proposal, I would like to use the template from the LCLS because I really like the thought behind it. For a beam time proposal, number one is the scientific case. And for the scientific case, remember the amounts which is behind it is why is this proposal necessary? What does it bring us in the part? Why should you use this facility? And why couldn't you go anywhere else? And again, in this discussion, this has to be fairly elaborate because it's a high value you're actually producing. So think of it like a big ground. The second point, and this is something which I find really nice because I haven't seen this in many other templates, is it's very useful to formulate specific goals of an experiment. And meaning that you should formulate one or two clear scientific questions which are suitable for a multi-day study. And this is again where the link to lab-based spectroscopy is. The lab can really help you of formulating those questions. Next point is experimental procedures and equipment. And these ones need to include how much sample you have for the C conditions, what are the focus conditions of the beam line and pump conditions if you do pump probe spectroscopy. You have to consider the time. How long does it take? Which needs to be under the conditions at the beam line. For example, facilities have safety procedures you have to go into and outside the hatch. You have to do remote control of certain conditions. So all of these things you have to consider. You have to also consider backup, means if your sample is, for example, damaging this time, what are you doing? Is there, we have alternative samples to have alternative signs. Can you use standard conditions? For all of this, again, like the last time, talk to a beam line scientist. Contact them, discuss your experiment before or use an experiment collaborator before you write the application. Not to neglect as a part of your proposal is your experimental team. Who will do the analysis? Who has the ability to prepare the samples and who will be at the beam time? If you're talking about teams of 10 plus people, this is not a simple question to answer. The last and most important question which maybe is most confusing is the technical feasibility. Technical feasibility. Number one, of course, talk to a beam line scientist because if you're running in standard conditions, if you're running a standard sample under standard concentrations, you can just use those standard conditions so you don't have to do the calculations. If you have to do the calculations yourself or if you want to estimate how long does it take to do the measurements, this is what I will go into details now. For X-ray absorption spectroscopy, the key is the height of the absorption or everything is relatively linked to the height of the absorption edge. Remember, if we excite the sample, we can, as soon as we get the energy above the ionization potential, we have to see a rise in the absorption or a drop in the intensity which goes through your sample. As you can see here, for example, this is an absorption edge and the height of this edge relative to the intensity you're sending in is the significant number which we use for all of the other normalizations. In the standard synchrotor, for example, these signals we're measuring here, the blue line would be what you measured before your sample, so incoming beam, monochromized before your sample. This is what you measure after your sample which goes through it and this one is measured after your reference volume. Now for doing these calculations, how high those edges are, there's lots of different software available. I personally use Haifaistus which is described by Bruce, who wrote this program, a souped-up periodic table for the X-ray spectroscopist. It's fairly powerful because you get not only the numbers of what the edges are over your lines are, but you get also a lot of other parts of the program. Inside this program, this is a set of programs called Demeter. It also includes Athena, which is data pretreatment or Artemis, which is used for fitting. And I would like to point out a little commercial that I will organize so we will organize with links and workshop on how to do X-ray absorption spectroscopy analysis next or in the coming spring. Now, with this program, I, for example, put in my sample and then I can calculate is what would be the absorption of this sample through my experimental conditions. For example, here I'm running a liquid jet of 300 microns. I choose an energy before the edge and I get how much of the sample is absorbing, which is mostly the absorption, the background absorption. I go after the edge, see the difference in absorption and I put in my solvent as I run a sample in solvent and get the absorption of the solvent. And from this one, I can see how much is actually absorbed by my iron atom and how much is absorbed by everything else. So I can calculate how high are those edge jumps? How high are they in reality? So how many photons of the photons which are coming in? Do I absorb how high is my signal? Now, since everything else is normalized in the analysis to this edge jump, this is a significant number. How high is your signal? Well, that's depending on what science you're doing. I'm doing Sains, for example, and this is a recent paper from my group where we used, for example, the pre-edge or changes of the pre-absorption edge, which is the direct transition into bound states. And we see a clear shift, a clear change of those edges. And I can normalize to the height of the edge jump, which is from here to here. I can estimate how high would this be? How big would my signal be? Calculating those spectra for Sains stuff, fingerprinting is easier. I would like to refer to this book, which gives an excellent guide step-by-step introduction how to do those estimations. For X-ray emission, this is even a tick harder. This information about how high is my edge absorption, how high is my total absorption is essential. You need to start with this part, but then you also need to know your fluorescence yields. Of course, each absorbed photon, a certain fraction of those photos produces a fluorescence for K-edge absorption hard X-rays. This is in the range of 30%. Now for Ivan, this is like in this case 35%. If you're in the soft X-ray range, these emission yields are very low. Now this is in the per mil, one per thousand range. And but again, if you know how many photons you absorb, you have the yield, you know how many photons you emit. And then you can go back to the information which we discussed here, how many photons you emit, combined with how many photons you can detect, what is your signal, what is your accumulation time, what is your preparation time. Softwares which help for X-ray emission, I can recommend PyMCA. Again, there's a whole bunch of different softwares. I've written one myself where you can put in your numbers and get out how many photons will you collect from your sample per time? So what is your feasibility of your experiments? Sources for further reading parts. This is the same page I've shown before. I can highly recommend for X-ray absorption spectroscopy. This book, the other books are also giving a very good introduction into these samples and into the different techniques. Last but not least, lots of my work, all of my work is done in big collaborations with lots of people only in Lund. This is a very long list. And I don't really have the chance of raising certain names, but everybody here be thanked for all the collaboration and for the long time of collaborative work. And I'm looking forward to doing a lot of more interesting science as all of my colleagues. That's all I had to say. I hope I have given a little bit of an introduction on how to do lab-based spectroscopy, what can you do in the lab, what you have to consider, where you find extra information. And if you then choose, and if you have the information behind how big is my signal, what would you need to do for writing a compelling proposal and actually how important it is to really put all of those informations inside your proposal. Thank you for your attention and I open for questions. Thank you very much, Denson. We really want to thank you for this great contribution. So I'm also our audience. So we have some people today live with us. And I would say that we will not record this part. So if people would like to turn on their cameras and address directly questions to the speaker, please feel free to do it. Because today it's really like a privilege that we have since we have a limited amount of audience. We have the chance to directly talk to our speaker. We can actually... Yeah, they can unmute themselves. Yeah, we allowed you all, guys, from the audience, to turn on your audio and to directly ask questions to our speaker today. Also to unmute yourself, yes. Okay. There are not many, I guess. Hmm. Okay, yes, I have a quick question. I have one. Also, if someone wants to do an experiment with your lab, how can they approach you? Or I mean, there's no proposal writing for your lab, right? No, I mean, yeah. Well, officially you can actually write a proposal because you're part of the laser lab. So there's a proposal for a procedure, and this is possible, but the easiest way is simply to write me an email. And also after my last talk, I have been in contact with a lot of the audience or quite a few of the audience, discussing a bit of the science. And again, this is always open. So in my own lab, I have mostly my micro-calorimeter and the two lab, two different sources. One is the micro-focus source. One is the laser plasma source. And there is, of course, a limited possibility or limited experiments are possible. One has to design, one has to discuss it. But exactly that's the interesting part is if you contact me, we can discuss the science. And as I'm not a facility, this is also a very open discussion. This is the same as with all the facilities. And I really recommend this also even if you have a small science, small bits of preparation experiments, all of the beam learning scientists do the same as I do, is that people can contact, they can talk and they can find ways of how to make test experiments. In my lab, it's about contacting me, talk about your science. And if you both find a feasible and practical approach and experiment, I'm happy to do it. This is, of course, done with a cupboard since we're not a user facility. But I can really recommend to look on the necessities of doing experiments in your own lab, because the investment is fairly small and it's not just feasibility for beamlines or for experiments, but it's also training because you train, of course, your students to train yourself and to prepare yourself for also the analysis. And a lot of those experiments can be done on a fairly low budget. Yeah, that's really important, but the point is especially for a young scientist to approach these new techniques rather than go into the more advanced and high-cost facility then to have these tests is really important. So I have one more question. It's more on the technical side. So probably I missed it also. How is the radiation damage compared to the synchrotron source and the table top source? That's a very good question, actually, because the flux of the sources, so depending where you're working at the flux range, but the total flux you're putting onto the sample is several orders of magnitude smaller. So depending how you define it, but if I, for example, take a sealed micro-focus source or mine is not micro-focused, but it's still a very small source, the total numbers of photons I'm putting on my sample per time unit is very small. It's also distributed over a right range. Now it's depending how do I design my setup? For example, if you're working on an iron as a sample, choosing a source where this emission line is close or just above iron, so you produce a lot of light which you're generating photons. That's, of course, a benefit. If you, for example, work on sulfur, I would use some softer X-ray lines. At the end of the day, the total numbers of photons you're putting on your sample is, of course, the same or similar to what you do at the synchrotron because you need numbers of photons to get the same signal of noise, right? The difference is what type of photons, what quality of photons do you put on your sample? In a lab-based, you put a broadband on a synchrotron. You typically, when I can switch back to this slide, I don't know if I can actually go backwards. Yes, so on a synchrotron, this is the underlighter output. So this is the photons you're putting onto your sample coming from an underlighter. If you slice out monochromatic, if you do monochromatic experiments, then all the photons you're putting on your sample are the photons you're using. If you do broadband spectroscopy, we can actually use the same slide, use broadband spectroscopy, then not all photons are contributing to your signal. So sample damage is a consideration. On the other hand, in a synchrotron, often photons are focused. And if you have to focus, if you have to work with focused beams, you have a high damage density. And I don't have to slide back, but you typically see even that you might burn a black spot on your sample. In a lab-based setup, it's depending how is your geometry. Because if you work with focused X-rays and focus them on a spot, you might actually put even more photons on this spot. Then you would do in a synchrotron. But I, for example, I work a lot for X-ray emission spectroscopy. I used unfocused beam. I'm my beam exposure range is three millimeters, four millimeter, big area. And that's why I use energy dispersive detection system because I do not need to refocus. I don't need the spatial constraints. On the other side, I count photons. So I am well aware how many photons do I need for my signs. So the likelihood that I put too many photons on my samples is also a bit reduced because I'm careful. At a synchrotron, when you run with a lot of flux, that's not always the case. Of course, you could try, you can try this, but there's the biggest difference. At a synchrotron, you get time. You get one day, two days, three days of experiments or sometimes only hours. And you have to produce it in time. So the time pressure is actually one, I find the limitation because it doesn't allow me to play. It doesn't allow me to put doses to play until when is it good enough. So I have a time pressure in which one I can do my experiment. So it's not as easy to answer the question. There's a lot of thought behind it, but the advantage that you can play at home has certain points which are useful. Yes. Joe. Hey. Thank you very much for your detailed answers. It's really... Yeah, it's a bit long. No, it's really a pleasure to attend your webinars because you're really detailed and I really appreciate your contribution. Anyone in the audience that would like to address questions to our speaker, please don't be shy, take your chance. Yes. Thank you. My name is Lucy. Thank you for the webinar. It was really informative. I am not a physicist. I'm a chemical engineer and I go introduced to Sinkatron last year through my supervisor. And I have been to Max4, I've been to D-Sec in Germany as well. My question is for someone like me that have not had any previous experience or knowledge about this, how can I get materials because you talked about your previous lectures or webinars because I mean, I could follow a bit, but I mean, a lot is still very confusing to me. So if I could, I mean, some material that could take me from the very beginning so I can understand step by step what this is about and most importantly, how to analyze the result because I have tons of spectra that I don't know what to do with them even though I've plotted them. So yeah, I just need help with this. So in short, for first in my division, be offering a spectroscopy course. Okay. Where there is one week of X-ray spectroscopy part of it. As a second, we will organize, this is part of links actually, we will organize one week summer school in the coming spring, which is focused, this year will be focused on X-rays and X-offs as a part. This is in collaboration with Max Four, with Kaiser for example, and part of the, of our links theme. And this is, I think would be for your problem an excellent resource for learning how to analyze data because that's exactly what the point is. Last but not least, I will also organize for myself in Lund, this is a course which, I'm sorry, the course from links will be online. So you can join from wherever you are. If you're in Lund, there will be a data analysis course in January, which is in general data analysis, not X-ray data analysis. But since I do the course, there will of course be examples of data analysis. But this is maybe not the fastest way, this is really focused on Python. And the last is, I can really recommend for Xsains. If you have machine Xsains data, I can recommend this book because this book goes from absolute zero step by step in how to analyze it, how to pre-treat the data, how to extract the data, how to prepare your samples. So for X-offs or for X-ray absorption spectroscopy, there is a book for XCS. To my knowledge, there is not. When this is why we also organize or we plan to organize a second summer school on XCS analysis and simulations. When this will be is not quite clear yet, but it's planned next year somewhere too. So in short, I recommend the summer school if you're still in Lund next year, in summer school next spring, all this book would give you, I think the fastest way of really analyzing your data. Okay. Thank you very much, Dan. Thank you very much.