Nano Nano - Neutrons in Space

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07/07/2017 Added

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Detailed video about the NASA DANSON research.

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[00:00:00.193](upbeat music)
[00:00:07.021]Our Sun emits different kinds of radiation.
[00:00:09.591]One of the most difficult to study is neutron radiation.
[00:00:12.355]Unlike electrons and protons,
[00:00:13.905]neutrons don't have an electric charge,
[00:00:15.577]and they can pass through many kinds of solid objects
[00:00:18.227]without being scattered or absorbed.
[00:00:20.376]This makes it difficult to build devices to detect them.
[00:00:23.219]In the past, most neutron detectors used Helium-3,
[00:00:26.139]which is usually made as a byproduct
[00:00:28.005]of nuclear weapons production.
[00:00:29.709]After the end of the Cold War, weapons production decreased,
[00:00:32.546]and there is now a worldwide helium shortage,
[00:00:35.512]so we need to research different materials
[00:00:37.485]that we can use to make neutron radiation detectors.
[00:00:40.664]In the UNL Detector for Analysis of Solar Neutrons Project,
[00:00:44.805]or DANSON, researchers at the University of Nebraska-Lincoln
[00:00:48.635]are studying effects of solar neutron radiation
[00:00:51.184]on two types of materials
[00:00:52.644]at the International Space Station.
[00:00:54.731](upbeat music)
[00:00:57.154]Well, there are several applications we
[00:00:59.538]can have with these neutron detectors.
[00:01:01.990]One is if these detectors work,
[00:01:06.345]they can help us with neutron voltaics.
[00:01:09.752]Same as you have photovoltaics
[00:01:12.098]where you receive light from the sun,
[00:01:15.227]and you produce some electricity.
[00:01:17.879]We could have something similar,
[00:01:20.035]but instead of working with light,
[00:01:22.899]we will work with neutrons.
[00:01:24.554]So, we will capture some neutrons,
[00:01:26.686]and we are able with these materials
[00:01:28.818]to generate some electricity.
[00:01:31.092]This is important, because for instance
[00:01:32.976]you want to send a ship to space,
[00:01:37.046]but you don't want to carry a lot of batteries, right?
[00:01:39.619]So, if you can generate this current, this electricity
[00:01:43.284]in the space, while the astronauts are traveling
[00:01:47.472]without any additional battery,
[00:01:49.665]that's one of the applications we want.
[00:01:51.819]At the same time that we are protecting the astronauts
[00:01:55.149]from the radiation coming from the sun,
[00:01:57.548]because these detectors, they will capture all the neutrons
[00:02:01.517]coming from the sun,
[00:02:02.767]so we will protect the astronauts as well.
[00:02:06.457]Neutron detectors are also used to treat cancer.
[00:02:10.425]So, we are working with a small pieces of detectors.
[00:02:14.029]We can make detectors that are smaller and smaller.
[00:02:18.245]We can introduce these detectors inside of our body
[00:02:22.024]to treat or detect cancer.
[00:02:24.380](upbeat music)
[00:02:27.328]Solar neutron radiation emitted by our sun
[00:02:29.514]can be damaging to materials in space
[00:02:32.472]like communication satellites,
[00:02:34.009]and they can be harmful to astronauts.
[00:02:36.056]It's important to be able to detect those things.
[00:02:38.728]What we're looking at with this experiment
[00:02:40.320]is materials that contain Lithium-6 and Boron-10.
[00:02:45.727]We're specifically looking at solar neutron radiation,
[00:02:49.516]and because neutron radiation from the sun
[00:02:52.727]tends to interact with particles in the air
[00:02:55.583]and break them apart and create secondary radiation,
[00:03:00.932]we're looking to actually get above the atmosphere
[00:03:04.864]that filters out and obscures that signal.
[00:03:06.339]That's why we want to be on the space station.
[00:03:08.737]Neutrons are really difficult to detect,
[00:03:11.415]because they don't have any charge.
[00:03:13.583]It's difficult for them to leave
[00:03:17.868]a mark on the material.
[00:03:19.468]What we do is we use a material
[00:03:21.682]that has specific elements
[00:03:24.357]that once they interact with the neutrons,
[00:03:27.799]they will decay into different particles.
[00:03:30.120]These particles are charged,
[00:03:32.477]and they can leave a mark on the material.
[00:03:35.497]The way the cube's designed,
[00:03:36.715]and you can see in the front
[00:03:39.083]there are these little pockets
[00:03:40.481]where we have detectors placed.
[00:03:42.580]I'm going to turn it to the side.
[00:03:45.689]You can't see inside from here,
[00:03:47.518]but basically they go from one diagonal to the other.
[00:03:51.811]That way we're getting different depths.
[00:03:55.694]The cube itself is a moderating material,
[00:03:59.636]which means that it's just designed to decrease the energy
[00:04:04.025]and slow the neutrons down,
[00:04:09.285]What we're looking at getting is how much
[00:04:13.332]these neutrons actually come into the cube
[00:04:16.392]based on where the detectors are located
[00:04:18.726]and how much radiation they received.
[00:04:20.322]We have our sample,
[00:04:23.043]and we have small circles of gold.
[00:04:26.919]Each circle will be one detector.
[00:04:30.725]In this particular sample,
[00:04:32.968]we have about 18-21 different detectors.
[00:04:38.381](upbeat music)
[00:04:40.525]Space man to install (radio static)
[00:04:44.487]the neutron detector and the views up
[00:04:47.304]We were on the space station on a sunset hatch
[00:04:52.306]in node two from October of last year to March.
[00:04:56.730]Now we have the experiment back.
[00:04:59.284]We've removed all the detector elements,
[00:05:00.984]and we're currently analyzing them right now.
[00:05:04.478]We can have different IV and CV curves
[00:05:08.666]from each of the detectors we are working with.
[00:05:11.923]These detectors have one side
[00:05:15.043]where we can capture the neutrons.
[00:05:18.534]This side is made of boron carbide
[00:05:24.537]And the other side is silicon.
[00:05:27.244]The idea here is that once we capture some neutrons
[00:05:30.751]with the boron carbide,
[00:05:32.466]it will create some particles that are charged.
[00:05:36.860]These particles are moving through this material,
[00:05:40.088]and they will create some electrons and holes.
[00:05:43.868]We can collect the holes in one side
[00:05:46.870]and the electrons on the other side.
[00:05:49.407]Somehow after the neutron capture,
[00:05:51.778]we are collecting some current.
[00:05:54.454]Measuring that current,
[00:05:55.821]we will know how many neutrons we've captured.
[00:05:59.842]Basically we have a back contact,
[00:06:01.666]and we have, depending on the sample,
[00:06:04.241]it really depends on which one it is,
[00:06:06.164]a different amount of contacts on the top.
[00:06:08.160]We usually keep the back contact hooked up,
[00:06:10.664]and then we just basically swap out the top wiring
[00:06:13.160]and just measure IV curves and CV curves
[00:06:15.494]for each little diode on it.
[00:06:17.760]Okay the IV curves are the current and the function
[00:06:21.361]of the voltage,
[00:06:22.423]and the data we're looking for
[00:06:26.607]changes in the width and orientation of the graph
[00:06:31.952]to understand how it's degraded over time.
[00:06:35.913]The CV is the capacitance versus,
[00:06:39.066]as a function of the voltage.
[00:06:41.173]We're looking at how that will also shift.
[00:06:43.688]They'll both be analyzed by Jen
[00:06:46.513]and backtracked to show how much they've changed over time.
[00:06:49.950]For the simulation,
[00:06:50.783]basically I have a virtual version of the cube,
[00:06:55.733]and I tell it what material I'm using,
[00:07:00.838]what dimensions,
[00:07:04.167]and where everything is located.
[00:07:07.557]Then from the STK software
[00:07:11.111]where we have information about
[00:07:13.941]how much direct sunlight we're getting,
[00:07:17.521]but we're not looking at light,
[00:07:18.480]but we are looking at neutrons,
[00:07:21.678]and that way when I'm using the simulation,
[00:07:23.818]I can put in exactly
[00:07:27.926]how much we're expecting
[00:07:29.701]to come from the sun and eventually compare
[00:07:34.168]what happens in the simulation
[00:07:35.664]versus what we actually read in the detector
[00:07:38.333]and work backwards and see
[00:07:41.666]how many neutrons we saw
[00:07:43.958]and at what energy levels.
[00:07:46.333]Now that the DANSON experiment has returned
[00:07:48.523]from the ISS, UNL researchers hope
[00:07:51.184]what they learn will help in developing small,
[00:07:54.213]effective neutron detectors for use on Earth and in space
[00:07:58.086]by examining the distribution of neutron captures
[00:08:00.822]in the moderator.
[00:08:01.972]They also hope to catch a glimpse
[00:08:03.330]into the nuclear fusion processes that fuel our sun.
[00:08:07.308](upbeat music)
[00:08:10.431]My name is Elena Echeverria,
[00:08:12.220]and I am almost a doctor in physics.
[00:08:17.011]I'm one month far from that,
[00:08:19.084]and I've been working with this project since three years ago.
[00:08:27.013]I am senior undergraduate in physics and mathematics,
[00:08:31.814]and I've been working on this project
[00:08:33.496]for about 19 months.
[00:08:34.927]I'm an undergraduate, and I've been working on the project
[00:08:36.809]for a little over a year.
[00:08:39.832]My name's Ian Evans, and I'm an undergrad,
[00:08:42.142]and I came to the program through my advisor.
[00:08:45.329]I'm Ben Swanson, and I applied with Ian
[00:08:47.563]through our professor.
[00:08:49.535](upbeat music)
[00:08:50.368]Now that's NANO.

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Nano Nano - Neutrons in Space

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