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[Music]

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[Applause]

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today I'm going to talk about the

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compact integrated Raman spectrometer

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thank you

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and basically this is a picture if we

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all know about the Euro Philander and

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the configuration that we were given so

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we're going to be taking a sample cup

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that we are going to be hand handed

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taking it into a sample chamber here

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where we will analyze this in its

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original state we may actually have this

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sitting outside in the cold so it had we

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get as low as temperature as possible

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but we like to look at the structure of

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the ice in its native form and we like

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to melt that sample and do chemometrics

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to look at quantitatively what the salts

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and things that are in the sample and

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finally we want to desiccate the sample

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so that we dry down all the solid

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material to the bottom of this clear

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bottom sample holder so that we can look

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at it with our raman spectrograph over

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here's a picture of our spectrograph and

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I'll talk a little bit more about this

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this is really based upon here a design

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we already have that I'll show you later

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and basically it's the same sized optics

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in this incarnation but this all fits in

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Box B but likely to make this a little

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smaller as we mature the architecture of

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the next two years so so any as I said

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the idea is to bring things in in its

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native form look things in a solid state

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this allows us to look at things like

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inclusions in the ice when when ice

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crystallizes oftentimes things that are

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not ice are excluded from and put in

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little grains that you can look at and

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identify so you get a benefit of some

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concentration by doing that we're

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interested in getting some quantitative

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idea of what's going on

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so by liquefying the sample we're able

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to do that and finally by desiccating

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the sample by book essentially letting

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thaw all the water boil off essentially

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at the bottom we'll collect all the same

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and hopefully get some concentration in

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that mechanism as well we have a 2d

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scanner in this architecture which allow

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us to scan and target any of the points

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throughout that volume so this is the

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specs on the instrument it's a 532 green

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Rama an instrument that it's been under

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development for I think 25 years and

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it's we're using a single frequency

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laser that has a really good spatial

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mode focal spot is 20 microns or smaller

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actually and we can vary the power from

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3 to 50 millivolts to avoid burning the

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sample so we can start low and move high

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and do that adaptively with the laser

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that we have we use a high F number

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laser and I'll talk a little bit about

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the fact that this allows us to do a

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pencil beam and we use f/2 collection

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optics which is I think one of the

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lowest F numbers of any Raman instrument

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out there to give us the optimal

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sensitivity working distance currently

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is 25 millimeters we're going to try to

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scale that down as we since what the

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samples being handled handed to us as

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opposed to having the instrument on the

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end of a rover arm like it was

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originally designed since we have a cup

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we don't have to have an inch of working

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distance and this will allow us to scale

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the architecture proportionally we can

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cover from 150 to 4000 wave numbers so

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this allows us to cover really low

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vibrational modes cover the entire

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mineral fingerprint region as well as

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the O h and CH stretches that occur

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beyond 3000 wave numbers spectral

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resolution is just six wave numbers and

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we have a signal noise ratio of five or

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greater when we're one centimeter away

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from best focus so one of the other

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features of the architecture is that it

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doesn't require you to to autofocus in

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any way and we as I said we have we're

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looking in one centimeter we're going to

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have a spatial resolution with native

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spatial resolution with our context

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imager

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15:04 by 2 mm so one of the reasons to

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use green light is if you look at the

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absorption of ice and water

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5:32 is at the very minimum and other

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wavelengths you my choice choose or

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something like 7 to 10 times worse

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so actually more than that so so Green

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is an excellent wavelength to use it is

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giving you a lot of people use 785 if

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you looked at the number of Raman

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spectrometer sold 785 is the wavelength

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that people use but rocks don't have

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very good run on cross sections so sort

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of the runner-up in terms of the pie

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chart of Raman instruments sold is green

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and those allow you to interrogate

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things like minerals with good with good

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response so because silicon detectors

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cut off at 1100 nanometers by using 532

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are able to catch that higher beyond

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3000 wave numbers it's very important

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for astrobiology applications let's see

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we also avoid photo and thermal

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degradation by avoiding UV light by

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keeping the power low as low as possible

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to actually acquire signal and we do

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have this issue I'm sure everybody knows

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that there's concern over intrinsic

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fluorescence laser induced fluorescence

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with green light so we're going to talk

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about a new technique that we have Carl

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Terry shifted excitation to deal with

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that problem and so so anyhow this is a

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graph of the integration time as a

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function of focuses focal distance and

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you can imagine this going into your

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sample cup which is about a centimeter

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deep and what we know is that with dark

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pyroxene we're able to maintain a signal

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noise ratio of five and that's one of

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the weaker Raman scatterers that are

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around so we use that as a benchmark

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pencil beam we have going into the

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sample has f15 which allows us

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essentially to be out of focus yet still

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be on a small area relatively small spot

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somewhere between 15 and

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30 microns all the way through the

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sample but we use f2 to collect even

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though we're out of focus you know when

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we're not at best focus over a

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centimeter we're still able to see dark

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pyroxene so this is the this is an older

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incarnation of the instrument called mm

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RS mm RS uses this kind of spectrometer

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based upon a holographic rating and a

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fiber input and this is the probe head

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which uses a laser that is contact

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bonded and actually doesn't work real

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well it doesn't have any temperature

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control so as it got colder in the Attic

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hammer things things didn't work out so

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well as the temperature change turn a

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laser on it gets hot the response

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changes so we wanted to change the laser

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and work on this this was a category 1

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instrument for MSL but fibers caused a

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lot of concern so that is I think

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fundamentally why this instrument was

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not selected for MSL even though it was

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looked at in the early stages of the

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puzzle development so this is the

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current picture of the instrument so I

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got rid of two fibers and that about

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thousand wires know only about 100 so

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these are these are the wires between a

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controller which is a cots base

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instrument and this is the Rahman head

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here's the architecture we start with a

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laser going through like coming back

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that is longer than 532 is dispersed

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through the spectrometer and focuses on

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the back through CCD light is a shorter

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it's illuminated by 467 nanometer LEDs

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we also have UV LEDs but primarily these

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are the ones that are used this gives us

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a context imager we implement light

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field imaging like Chris does similar to

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what Chris does so that we don't need to

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implement an autofocus either for the

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context imager so here's a picture of

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some radiation testing we did with our

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JD su laser and so we ran it at two

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different currents that's kind of hard

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to see but the we're seeing hardly any

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change there's like a black shadow

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around this versus the blue

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for the 600 and the ends it's sorry for

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red and then for and and so essentially

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you can see very little change and you

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see the step like behavior that occurs

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as you switch across modes of this laser

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so it maintains single mode behavior

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over a wide distance and consists of a

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pump laser a KTP doubling crystal and a

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host crystal the vanadate laser that

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leaves us between these two places so

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anyhow this is the art this is the

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architecture of that laser we because we

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have a birefringence crystal did student

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and doubling it also causes

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implementation of something called Ali

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Leo filter which basically will vary its

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face as you teint change the temperature

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as you change the temperature the laser

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slightly what'll happen is this will

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start allowing this this mode or this

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mode of this motor this mode to lase and

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that's what's giving you the behavior

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here that we're seeing so what we do is

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we use this because we know that the

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Raman spectrum will shift with weight

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rady with wavelength shifts but the

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fluorescence things for s the lowest

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excited state and this will so this

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allows to separate these two things so

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we observe the raw spectra set for let's

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say 10 different samples we look at that

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and we mathematically solve for the

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fluorescence component separately from

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the Raman component and we can show

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here's some examples here of enstatite

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and here we have Dena caucus radiate

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Duran's which happens to have a

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carotenoid in it that is made without

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the use of light by the way and so this

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is a reasonable biomarker and we can do

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because green is a longer wavelength

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than UV you see longer molecules like

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carotenoids and you can get resin

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enhancement down to symptom - well or

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low picomolar type concentrations so

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we're also using light field imaging and

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I'll try to skim past this but since

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Chris talked about this but we're able

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to essentially do it

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we can look at various planes all in one

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shot and do this without any moving

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parts just wanted to show an example of

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sort of what happens in the in terms of

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RAW images as you put the images

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together you essentially can tell by

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looking at you cross-correlate these

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little sub regions and this allows you

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to get range information and allow you

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to all of them lace stitch the image

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back together and finally this is our

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cameras so so we have two different

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cameras now we have to mitigate issues

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of radiation so replacing what we're

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currently using the 47 - 20 tip with a

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much rad heart hard 347 - 20 chip same

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amount same electronics lower voltages

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bias voltages to make it operate and and

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so this has been developed by E - V and

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so our currently just essentially taking

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that chip in implementing electronics

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for it it's very similar to what we

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already have and we can't use the ki

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2020 which is what we which is in Mali

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but it's just not going to work with

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radiation we're replacing that with a

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CMOS CIS 115 which is used in Juneau and

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as they said where we love this

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architecture but we're gonna have to

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shift to special optics to make sure

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that they don't turn dark with radiation

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either here's two examples of the lasers

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I talked about this one this little tiny

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one we're also looking at that we just

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exposed to 10 times the radiation dose

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it's on Europa and it's working great so

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I think that's it this is a summary that

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I'll let you guys read but if I can

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answer any questions that would be great

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thanks

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any questions good I particularly like

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the use of the shifted laser wavelength

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to address the fluorescence background

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and amusingly in another life I spent

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about 30 or 40 years doing Raman

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spectroscopy and way back about 1992 and

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II Shrieve was working on looking at

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photosynthetic reaction Center residents

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Raman where the fluorescence is a real

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killer and we invented a technique which

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we called shifted excitation ROM on

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different spectroscopy

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so the acronym serdes never really

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caught on because it's kind of ugly but

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if you don't know about the reference

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I'll give it to you oh I certainly know

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about sir thank you very much so that's

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sort of what started the whole thing

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going this is search you bet

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well by the way I want to also just just

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offer up that we are looking for MPP

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postdoc applications which are coming

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due so if any of your students or any

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students in this room won't be