 So, the idea with this is it's a data analysis talent which really should help you understand much better the time of flight aspects and how the data will form and what you can get out of it. And so this is a short exercise and the idea is you go through it with, you know, by, I think it's a Friday lunchtime, there are four questions to answer, but it shouldn't be mass, mass work, but it is a good exercise in terms of helping you understand time of flight. So, yes, I'll pass over to Robert and I can explain the exercise, but there's also videos online to look at. Yeah, exactly. It's not meant to create too much work for you, but really intended to give you a little bit hands-on flavor to a data set and then use some of the functionalities in image that are relevant to it. I realize also over the time now that I keep explaining the same functionalities that are really buried deep in the image shape menus to different people who want to look at this data, and there are actually many, if you really want to analyze for example you may want to fit these break edges and so on, but that's not what this exercise is really about because if you want to do these fitting tools, you should anyway look at the data manual on the side so you are not just getting some fitted parameter from a break edge without actually getting a feel of the statistics in that. Image J is extremely helpful, so this exercise really deals mainly with that and loading an image tag into image J, so I will share just the screen of the exercise. So you download the program that should be straightforward, then the data download, you should see something like that and I like just to download, I mean what you really need for this is the open beam tip. You can see 3.9 gigabyte and the samples, let's say A or B, the samples A tip. These are so-called multi-tips, so it has 4,000 images in just this one file, so that makes it easy to share and you can just like you will see in the tutorial, drag and drop it in. If you have some memory problems with your computer, I recommend you're just going for the small version of the same, this is less images says open beam small tip and also sample A small tip, you just download that it's much smaller, a bit easier to handle that is actually all you really need. There's also the other image from the tutorial there where I looked at sample B and also a calibration sample and I also put this excel sheet here, so we just, and what is just prepared is, it's a tough channel because as I said, the images, they are 4,000 images and every image is 0.01 millisecond apart, so it's 40 milliseconds and I already converted it to wavelengths for you, so it goes to 7.9 angstrom, so that is here for this channel for the 4,000 images. I did prepare also in case you've worked with a short, with a small data, I just use some binning function here in Excel and where actually the images are binned by 5, so it's image 4, 5, 6, 7, 8 and then image 9 to 13 and so on and then you only are left with basically 800 images in that stack here and again it goes to 7.9 angstrom, but you only have to do 800 images and there's some spatial binning as well, so then this would be the relevant wavelength for you, so I already pre-prepared that for you and then you can put your sample in here and do the open beam and follow. I think everything else is in the tutorial, what else is important, what is maybe not so clear in the tutorial is that the images, and this will often be the case, have been acquired with different acquisition lengths, so they have been recorded for a different time and when you do want to calculate the transmission and you divide the sample by the open beam, of course you want to make sure that that you're normalizing to the same duration and so I put this normalization factors in there, so the open beam has had 742,000 something neutron pulses from the J, this data is from the Radon beam 9 at J-Park and I just said okay this is a factor of 1, the sample that you should look at has had actually much more pulses, so it has was acquired for 1.6 times longer, so you should normalize this sample stack dividing the whole stack basically were 1.66 before you divided by the open beam, so these are the normalization factors for the different samples taken in this measurement and then there are a couple of questions, sorry, for you to answer, and that is down here, so you can watch the tutorial, there's the first tutorial, it's about I think nine minutes, that you just play from YouTube hopefully. I'll come to the short tutorial, I would like to show, so I hope this works, let me know if you have problems, we will not watch that now, and then there are a couple of questions to answer. The first thing is, if you look at the incident spectrum, either from the open beam most likely, or you can also principle do it from the sample, what can you say about the incident neutron spectrum going back to the previous lecture, are we looking at actually a coiled beam, a thermal beam or epithermal spectrum, there should be some conclusions that you can draw from just looking at the incident neutron beam spectrum by using this plot Z profile function that I explained in the YouTube tutorial. That will be the first question, the second question is, I provided also some reference data here of a theoretical position for a BCC steel alloy, and that is actually, you should actually download the calibration sample actually as well, which is a BCC steel, so and here you have some reference data, actually this is in attenuation coefficient not in transmission, so it's inverse, don't be confused why the breakage goes down, doesn't really matter for this tutorial, you have the theoretical break edges in this excel file and then you download the experimental one, and the second question is, can you find out what is the flight path, and you will know this formula from the lectures, flight, time of flight, you have the wavelengths and you have the flight path, and in the excel spreadsheet you can actually change the flight path here, so question to answer this 20 that is entered here, I can already tell you it's not the right flight path, you will have to change this number, that's you don't have to change any of the others here, but you have to change this number and come up with the right flight path, calibrated back to the instrument, and then you should go tutorial number two, which is now dealing with the sample A, so in the first one, in the first tutorial you need the calibration sample and the open beam, in the second part of the tutorial you need the sample A stack and the open beam again, and there are three samples, and in the tutorial I'm telling you a few tricks how you manipulate, starting with this 4,000 images or maybe if you start out at the 800, how to compress these down and to bring up contrast that is due to diffraction, and that was, we talked about a bit just before the break, this Fernando, what if this presentation is still up, because it was basically that question, I just bring it back up one more time, what you should try to do is here, you should sum images in a clever way, and I'm explaining that in the YouTube tutorial, you should sum up sections of the spectrum, so between here and here, let's say there are 200 images, so you will sum up parts of the spectrum, and then parts of the spectrum behind the bracket off, and you can create ratios, you can divide these 200 images by the sum of let's say these 200 images you create, from these 200 images you create one image and of these 200 images you create 200, and then you divide before and after, and then you will see only the difference that is due to this diffraction and actually things like density and so on are normalized out, so you can bring to the surface now contrast differences that are due to diffraction contrast, and that will be that part of the exercise, and the question to answer there is there will be there are these three samples, and you should answer about the sample 00108009, where spatially these are tensile samples, I can already tell you they were pulled, where do you see differences due to diffraction contrast, and I explain in the tutorial that this sample is a specific steel that has also a phase transformation under load, so a trip steel, and there will be phase transformation happening locally and maybe also some other things due to diffraction, and you should highlight ideally you make maybe a screen print of your final image, and just describe it or you highlight this some markers like I'm drawing on the screen here, where spatially there are differences between these three samples, and then when you have manipulated these samples good enough, and I'm hoping that tutorial that I'm doing on another example on sample stack B, you will be able to create this diffraction contrast by summing and dividing images, you should also see that one of the three samples 00108009 has actually another feature that the other two don't have, and can you find out what it is, and there are actually two major differences that that sample has compared to the others, so can you find out what are the two major differences, and if you can at least find out one of them that would already be great, so that's basically it, and don't spend too much time on the fancy report, I think if you just drag some screenshots into like a Word file or PowerPoint or whatever your thing of choice is, and you can type the answer to the four questions, and then you can just email me the whole thing we saw it's best if you do that before Friday on noon, because then I could show as part of the exercise, I guess this shouldn't take long, spend 10 minutes to show the results of what you should hopefully have obtained.