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Basic Physics III Lecture 26

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Automatisierte Medienanalyse

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so we have this experiment Rehan 0 . 0 1 6 micro curies possible sample objected contains material culture and after 1 hour ourselves or washed and a 70 percent efficient detector reads 120 comes from the cells and the question is how much of the projected cost debate absolved then 1st of all in this problem the only 1 after 1 hour of decay time or be half across borders is much much longer than on leaders the dollar no decay has attacked the Soviet cities the same as the original activity can be stopped by calculating the fatigue and reused the 0 . 0 1 6 Mike Korea purchased 1 . 6 per cent of the minus 8 curies and then the next factor the 3 . 7 times the head is because version from jury Tibet Becker and Soviet 590 to that curls uh disintegration 2nd and counter therefore should read 0 . 7 China's 590 to riches 440 pounds if all of that was the result of that would be 24 thousand 900 can't admit however that can't read 720 counts per minute therefore the ratio of the 720 and the 24 thousand 900 1st a fraction of the cost but molecules that can be resolved and that corresponds to 2 . 9 % the 2 . 9 Percent of prosperous absorbed that can be measured using this technique so today
will be mostly of Balladur application of radiation so view most straightforward application of radiation medicines and radiation therapy lose radiation to destroy I wanted to show cancel grow or or benign tumors as well but can you lyrics necessary this is particularly effective because cancer shares defined as an uncontrolled rapid production of cells and such cells the producing often they are particularly vulnerable to radiation that such a bit more so than healthy cells which Her producers however it does till healthy cells as well and radiation therapy often uses radiation sickness page so it's a balancing act usually ever therefore tries to not radiate entire but just that part of the broader particularly to identify and small ones usually various on the eve of radiation to limit the damage to house surrounding tissue only the tumors always radiated surrounding tissues of irradiated half the time the radiation that is needed for this therapy can be said that generated for example the X-ray using accelerated all between 200 kV and 5 and also can use of protons neutrons France and Ireland from accelerators or what can use a radioactive sources such as cobalt 60 if the source is small enough no 1 can trace it inside the body for targeted localized destruction of the yet another time at 2 the 2 were organ that absorbs a certain type of chemicals that can it radioisotope over those chemicals to target the destruction of a perfect example of that is the usage iodine-131 to destroy cancer of the additional benefit in this case is that the thyroid tends to absorb the iodine and particularly in regions it grows so therefore it is a more targeted to would be otherwise I'm
not a good candidate of proton beams that because of proton means they did their deposit their energy on equally along their power so it was only a region with a very dear to him for energy policy memoranda after some distance almost all the deposited 1 go and aware that distance depends on the energy the proton so therefore has sort of three-dimensional control radiation damage occurs it works so well that I dutifully physical size of the tumor actually whoever proton beam of several energy otherwise who would destroy the entire unfortunately a proton therapy requires large accelerators which expenses Our until recently only if you are hospitals I was another medical benefits to radiation is 1 continue was a so-called radioactive traces that needs to replace an almost nonradioactive told radioactive wants and if you do that right substances that because the area activity acts like a pain tag of of those turned out so that they can be traced to the bodies using guy goes scintillation counter and a very good example of this using carbon-14 or what resumed to check for example Hall of food molecules are adjusted and will the transfer so 1 can
make things like this bottle radiogram of relief using carbon-14 or on the bottom you can see a replicate dignity and in other words such traces can also be useful for research on can determine how amino acids of soon to sign those studies sold um membrane permeabilities burst when they used for diagnostic Perpich purposes and medical science 1 usually uses a sysop told called 99 techniques and it's a metastable state of meaning that they debates saddam up with a half-life of about 6 hours and its form in the beta decay of 99 wounded and a combines with many compounds so when choosing the right compound 1 can use it as a tracer in many different organs or regions and usually a single down detectors moved across the body however 110 also it was down take a picture and the case of such a camera 110 even make movies meaning a time-dependent picture and those pictures are called to grow was simply stands for us and later for medical imaging a lot of progress has been made using SO copper so-called Top Biography technique so in classical X-rays all you this is a shadow image so you'll have your X-ray source China's food muddy and you have a film on the other side of the body and shadow on depending on how much of the expertise result by the different density of 2 she best that is a little about diffraction refraction swords only absorption and scattering a mixed picture in the CompuAdd are tomography and tomography comes from Thomas meaning shop or Kwan losers instead of calling being meaning that you have to pass the X-rays hold on the air this collated being with them detected the collimated detector also so you get away in regional defined direction well-defined and then 1 takes many angles and positions CompuAdd said image 1 slice of the time and this technique is also review the CT or see 18 were Barresi 18 means computerized axial tomography while it's possible to proceed this way with a single detector it is not particularly useful because it would take a long time to take all the images of all of all the angles and so on and the patient would become impatient want to the kid With
past scanner typically uses of the so-called pending meaning that generate a B X-rays on 1 side of the patient patients lying down here and so you generate that being that fans out in many directions and entire array of detectors that picture of and then you rotate a whole assembly around the patient to get different angles if 1 wants to owe a debt to take pictures even faster than that because as a sort of limited by the speed with which you can rotate the assembly around just you can have an entirely detect and you generate X-rays having an electron beam that is then scanned across the top it also so wrong so instead of rotating an extra resources just scan electron across the target the salons page from all sides and only generates X-rays at 1 instance of 4 about from 1 part of the from 1 direction on and it's much faster scan beings to mechanically rotates so those so-called fixed source machines the analysis of
tomography how to generate a picture mathematically somewhat involved however the principal as well it easy to use logically defying pixels for your image of script pieces of of the body from which you wanna determine how much x-rays were absorbed by this particular pixel but you have the measurement you have our projections on and on various acts so let's say they have a absorption stool 4 5 9 4 4 6 take war angles of angle want a baguette the Sun left pixels to plus 5 act and 4 plus 9 on the right size for angle we get to class war the top 5 1st 9 at the bottom and for angles freed get the diagonal To before we get the other of 4 so far and then run uses mathematics to reconstruct the year your original novels tool for for mindful of you from those measure barley and this technique works in Fiji also 1 can actually assembled a treaty image and the more detailed 1 wants more scans are required to have enough information to be constructed in the NDA which is often shown and false Carlos tool emphasized particular features like this particular area in the brain and 110 up clients To ultrasound and radioisotope told emission tomography as well and then finally to what we can magnetic resonance the emerging from talk late so for the emission tomography uses a trace as a source rather than an extra meaning you make the body itself global soldier then detect and computing image as OCT when I won only gets 1 slices usually 1 users down on was a trace of Yukon got lost about art transported easiest Out of the Body so this is called a single photon emission tomography team earned the top seat span of 4 of brain with particular brain disease as a sample if I'm out useful technique is to use positron emitters such as carbon 11 13 oxygen 15 on Florida 18 and the idea that that if you have a positrons admitted they don't go off him positrons travels fall short distance but not very far mandating composed of Allah France and only relates makes tools back-to-back full and so I didn't have a detector surrounding the patient which look for a simultaneous detection of 2 photons back-to-back and that reduces the axis of what among which those for property then taken image using tomography technique that preceded and all of those are called a cheat sheet 1 hour particularly interesting technique uses magnetic resonance and talk about the medical residency 1st talk about particles that's something we have uncovered so far particles like away from for example have intrinsic angular momentum and this is called the spin S and this intrinsic annual rent just like any other angular momentum is quantized and cardinals either Harare spins euros or screen H. spin off each box 3 times age Volvo to 2 times and so on magnitude of angular momentum also magnitudes squalor due to the weakness of quantum mechanics is not just her spin time span but it's actually spin times plus 1 so if you have a say in age particles and has the magnitudes clear of H tough all but 2 it Thomas H. plus 1 0 with 2 or 3 times 8 square for the easy component Welsh this spit annual momentum is elected ranges from from minus class for example for each bowl to ponder go from minus a bomb to trust each and the X and Y components and quantum mechanics that don't exist simultaneously with Ozie component because the uncertainty principle makes them maximally on measure busy component and X and Y don't exist to measure the x component lines on spin tied to whom admitting moment and that sort of thing is the main because it you imagine that electrolysis actually lived through ball cannot that it's spinning around its axis and developed honest charm and Selina Chow spinning around and that sort of a similar to Loop current current air produces magnetic field dipole field and that can't be quantified the Medicaid
moment since the angular momentum all of this is quantized Norman moment is also on and in the case of ELECTRONIC there 1 defined all manner of time on the quantum of magnetic moment similar where's the ball radius quantized there the radio and it's given us twice I would contest adding moment we made it moment is quantized in in units of the Womack part but if want to get the relation between the state and the moment it is not simply a new enclosed there s age bomb but there's an extra factor was so good drummer integration and yeah that factor for electrons approximately 2 so once we have a magnetic moment which you can calculate political spin it has on energy in a magnetic field the energy classically of magnetic moment in the field every moment oriented this way amendment field already hinted that and that's entangled favor between them and the energy it's uh it's given by the size of the moment the size of the magnetic field the cosine of the angle between the end of my Messiah the magnetic field
singles all particular direction space and that defined the acts the so if there's no magnetic field applied and the spin could point in any direction because it's not measure but if you applied magnetic fields and 1 particular direction identified and that is even called examples for Carnival spins and in case you have heard recently this so-called an expose on most discovered in Switzerland and that is actually a 1st fundamental particles that has no was spin all and that's the so that makes other particles maps or the quantum of the field the partial if so that the other try on the neutrino the clock the neutron and the proton all of those have In 2 photon and warm weather grew honestly the quantum of the strong force just put on a condom it has twice as much spin has been reached on however because them at a photon as since August 1 1 0 busy components doesn't exist you can't have component of the spin things you can only be Class H minus for the W and Z those arms and those of a crime I want to point of the weak force it also has a of each but all 3 components exist because those finally the Greenwich time but the quantum of the force of gravity it has just been 2 H if a general or all the polls on remember particles can be the people's arms from all goes on an integral spin and all the nuns are a speed that is up number times age so much about this the speed now all of the magnetic moment for the neutrino but we don't know what the magnetic moment is turned on it's small that's it's less than 10 of the minus 10 million units of former where ballot farmhouse has 1 more so for the electron this jury integration tool and since the the spinners aged up who was canceled and the air out of the jobs 1 woman for the proton this may show summary complicated numbers about 2 . 7 9 2 0 8 and the spinners also tour and we then define a similar planted years for lack of time but replace the outlook from Mosul protons Larsen and it's called Nokia and Tom and so would be Proton has a moment of 2 . 7 9 tool 8 and Oakley amendment on neutron even tho its electrically neutral it still has a moment it's actually has a negative of integration which means the magnetic moment points in the opposite direction as and fear ratio is his 1 . 9 1 part and because it has a lot of moment it must mean that neutron has structure it can't be a fundamental particle and indeed I think that it consists of the walks U D D if you see what happens when we expose look and since the appearance of spins Tokyo have Spain also we on half but certainly the hydrogen look which is just 1 proton they for possible states the 1 they aligned with the magnetic field he called up the other longer and line which is we call so there's some an energy and difference just like for classical between up and down and that energy differences over the extreme case between Cos they don't plus 1 coast of minus 1 or 2 times the size of the magnetic moment peak times magnetic fields and so on the cause of those energy levels and those energy levels are proportional to the magnetic field that means that we can defying the size and the size of the transition between just like any other energy levels of atoms an electoral medic transitions will elect a month ago radiation that carriers the nucleus spin from 1 state back so it's kind of like defining all energy levels and a new atom controlling it by magnetic field and that is what is meant by and my medical residents nuclear magnetic resonance so since we can have
transitions between those energy levels and you can actually calculate the frequency of b electromagnetic wave that is required to make this transition since this depends on the magnetic field which consists of a we applied external magnetic fields and those that that is produced by nearby other particles electrons another nuclei we can then control the air actual residents frequency which is simply magnetic field divided by times twice the magnetic moment of the proton a case of hydrogen and then it gets this formula that we resonant frequency those energy levels can be changed from 120 others 42 . 5 8 times the external fields of test letters fools for out free proton like a year in the hydrogen soul is that if the the protons are bound slightly D 2 wins to a different but there is a 42 . 5 8 and megahertz for 1 Tesla field listen to the radio frequency regional of the spectrum with letters particularly useful because we have lots of frequency technology to detect such radiation and it can pass outside of the body when it's produced in the
so as an example it's actually calculators formula so that that's calculated magnetic resonance frequency of free protons and no 1 has ammonitic field so at 1st get the can magnetic moment so that's the funny No. 2 . 7 9 toll 8 German integration each tool and put on the proton and that is on the floor the proton since age Rachael Pine since the frequency of the energy difference old or twice magnetic moment times field divided by age and gnarled plunder and to I have a formula for the moment this just above the knee gets too . 7 9 2 8 times the elementary charged magnetic field divided but to the proton and Paramount before that and we find out it's indeed for 2 . 5 8 4 1 test that now we can actually applying for magnetic resonance imaging so we control the energy levels by field strength solar for example we can have non-uniform field with different parts of the body art in a different strength magnetic field and they have different resonant frequencies so that is 1 way to work to localize the radio frequency is coming from war 1 can excite all leave the hydrogen yeah hitting them with 1 Radio Free the entire body and then be fully excited and victory the frequency to change the field until not more and better still bear the most useful technique so you 1st
apply 0 0 uniform field and you get to particular energy levels everywhere the body and so albeit an all been no clear driven in the opera energy level and then in the step told you change leader so that this is the case is everywhere and instead told you change magnetic fields for those energy levels of little change depending on position and all we the up energy levels of and this fall down and emit different frequencies different radio frequencies depending on where on the body and then you can
a these Tom biography
techniques to prepare to turn this into images this technique of 1st exciting and then waiting for them to that's called spin Ekwall because it's kind of like you hated the radio frequency and then a short time after what's Radio Free ensues come back technical and gives you a resolutions on the order of Milanese so that means it's not so bad compared to other techniques so conventional X-ray and resolutions up 2 half a millenium or a CT scan intended offer Malone and Nokia trace us will give you a centimeter typically for example a S P E T and positron emission level defeat of 5 mm and VMI can be pushed up to a half of ultrasound by the way Kumar linked but 1 great advantage of EMI that a radiations radio frequencies so it's not that means it is harmless to the tissue radiation a jury said let's talk about other types of Tokyo reactions Nokia decay is only 1 type of reaction for example even rather forward himself observed that some of the other particles absorbed nitrogen gas and protons on and 1 can understand that this no clear reaction with the air interacts with the vise chairman makes oxygen 17 and I want Proton and sometimes uses short dictation like 40 other nuclear reaction already conduct problem 14 produced in the atmosphere on nite options and sold this notation just means the same thing as a neutron plus hydrogen it's problem called for and just let it had killed well useful nuclear decays can To well used nuclear reactions it was saying the the particles before and after if that killed is bigger than is your you exothermic reactions and and the agree cheats close but in much the same thing as a chemist and to balance the reaction equation you have to conserve energy momentum and movement on charge their number that upon that's just too look at 1 a brief example let's say be Collins 13 with protons and out comes nitrogen 13 and you can this happened this year a carbon 13 rift with and happened to abolish the 2 . 5 from what we do is the same as for the became a look at the Masters carbon team and for hydrogen 1 1 so before we have a reaction take place have a 14 . 0 1 1 8 0 0 atomic units and afterward we just have a 13 the neutron we have actually slightly more last 14 points as wonderful 4 0 4 you so you would say well that means reaction can't take place but it's not true because we have an extra 2 immunity from protons that we need to take calm so if he look at the the vast difference and be converted into energy units find that it corresponds to flee immunity so since have only 20 the reaction cannot take place but it can take place . 5 actually it's probably doesn't take place even 4 . 5 million consonant oval calm cool area and so would require some extra activation and our . 5 sunlight but at least it is possible that this reaction takes place with 3 . 5 and Fairbrass the 1st to
realize that Nokia reactions and neutron bomb Bob a useful technique because it can avoid the crook propulsion the coup barrier it is therefore more effective to trigger nuclear reactions and produced many annualized hopes it's just bombarding Isaac hopes neutrons and making you worked on and he also realized can generate new elements are bombarding the heaviest on purchase uranium with no chance for example I can produce and the 2 Newman told by neutron bomb the and people in Germany following on his studies they discover that you can actually but the into smaller pieces by bombarding them with chance the right kind and that is called a nuclear so it's different from decay because a large pieces come life a krypton Moclips for let's talk about that nuclear power on the last film where moments internal clear parcel recently has gotten a bad name birth think we should all like look how because they can only exist with no stars like the Sun provide constant supply energy a long periods of time only because their power illusional nuclear fusion of light look at the 2 sophomore look past then interest in me for the 1st few weeks of light look and see stars like the son to take place require the strong and the weak for us for Nuclear processors who also required the electromagnetic force transferred managing and you will acquire gravity to hold not so at the start of games Nokia reactions by making deal for from from hydrogen which is just what a single proton and the question is where does this Doggett leaner you try to make needed full because in for a try so it at told make neutron honest Kwan wrote Proton so we need to make a neutrons out of protons and that violates farm so that are therefore we can be there emit the positron action war we have to to absorb and I try and then the charge will be considered the absorber knowledge torn and electron plus toe for their child Wan and sawdust coming to you so however that runs into another problem that nuclear reaction because you also have to conserve the time amid absorbent ELECTRONIC than we have changed the tone and so that problem can be solved by initiated Chino or not absorbing a maritime trade meeting the neutrinos easier so that means that you have a possible basic reactions proton proton goes through a series reached 1 plus positron because we know all America proton thus Alig plant was protons makes deuterium plus plus trees the 1st process called the PPE process and the 2nd 1 is called for man once you have to TOUR UK and refuses the mother Proton to MCI's class Obama a tool such helium freeze can refuse and make a case for war plus 2 protons and the stock and then generate energy so in some total me hair butterfly assurance that must To Alex persist last neutrino us and plus to . and a releases 26 . 7 and the entire process still
there are other reactions that can also happen for example you can make Beryllium 7 choosing helium 3 and 4 or you can even make born 8 by refusing another Proton to the Bruins 7 and all those processes that figured out by baited who received Noble Prize for this look a cult leader Li from lights put for different types of processes the 1st lunches suggested Ross office Stanley Eddington but he did not figure out how to make a neutrons in particular because when he suggested that the existence of neutron known and this 1st promises of making neutrons chance out of protons is important because it requires the weak interaction and that means the process is very likely to happen and for that reason stars don't just exploded and split-second but run over millions of years so as while important that there's a week process involved finally once all these hydrogen is exhausted and then stock and could lose energy by fusing the for example helium atoms can become 1 Coburn still if we be
summarized those those processes this process on the left this called PPE chain and this is how all sons generates energy and then there's a seconds as cycle of catalytic cycle copper Sunil cycle with rich heartless stores use their energy but in both cases hydrogen is burned helium and energy and this uh triple I'll reaction carbonous produced on the oldest art and there's actually direct proof of the PPP chain process because media and train on us the maiden reaction penetrating they can't even get out of the cool off the sun and
they have been measured on the 1st by the pioneering Davis and this is the energy spectrum of 8 different types of solar neutrino ought to exist at all most 8 3 different species have been uniquely identified there's no direct observation for seat in old cycle so far by air you can infer from the sequence of styles a strong so let me finish here
and I will summarize this check on Friday thank you for your attention
Schaft <Waffe>
Radioaktiver Zerfall
Magnetisches Dipolmoment
Dünne Schicht
Satz <Drucktechnik>
LEAR <Physik>
Stoff <Textilien>
Magnetische Kraft
Angeregtes Atom
Schwimmer <Technik>
Dreidimensionale Integration
Relativistische Mechanik
Zelle <Mikroelektronik>
Zelle <Mikroelektronik>
Kette <Zugmittel>
Optische Dichte
Elektromagnetische Welle
Spinner <Handwerker>
Schwache Wechselwirkung
Volvo Group
Verband der Metallindustrie Baden-Württemberg
Scheinbare Helligkeit
Source <Elektronik>
Closed Loop Identification
Erwärmung <Meteorologie>
Familie <Elementarteilchenphysik>
Spitze <Textilien>
Elektronisches Bauelement
Walken <Textilveredelung>
Magnetische Resonanz
Elektrische Ladung
Magnetische Kraft
Metastabiler Zustand
Stoff <Textilien>
Hydraulischer Aufzug
Radioaktiver Zerfall
Optisches Spektrum
Kaliber <Walzwerk>
Magnetisches Dipolmoment
Quark <Physik>
Elektronische Medien
Dünne Schicht
Tunnelstrom-stimulierte Lumineszenz
Direkte Messung
Emittergekoppelte Logik
Spiel <Technik>
Ton <Akustik>
Stabiles Isotop
Nichtlineare Raman-Spektroskopie
Source <Elektronik>
Magnetische Kernresonanz
Masse <Physik>


Formale Metadaten

Titel Basic Physics III Lecture 26
Serientitel Basic Physics III
Teil 26
Anzahl der Teile 27
Autor Smy, Michael
Lizenz CC-Namensnennung - Weitergabe unter gleichen Bedingungen 3.0 Unported:
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DOI 10.5446/12962
Herausgeber University of California Irvine (UCI)
Erscheinungsjahr 2013
Sprache Englisch

Inhaltliche Metadaten

Fachgebiet Physik

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