Nuclear Detection at AUA

The AUA College of Science and Engineering in collaboration with MIT is hosting a course on Nuclear Detection. 

Lead instructor:  Prof. Areg Danagoulian, MIT (aregjan@mit.edu)

TAs:  Grigor Tukharyan, TBD

Language:  English (lectures); English and Armenian (labs)

​Dates: June 20 - July 1 

Times and Location:

          Lectures:  14:00-16:00, 314W PAB at AUA (June 20-27)

          Labs:  14:00-17:00, 605M at AUA (June 28 - July 1)

 

 

Note:  MIT is an equal oportunity institution.  We do not allow discrimination against gender, race, religion, political views, nationality, or sexual orientation and/or identity.  This policy applies to all our programs -- whether in the US or in Armenia.  We are also strongly committed to diversity, inclusion, and equity.

Course Material

You can find most of our lecture notes, course materials, code examples etc. in this Dropbox directory.

Additionally, here are some useful links:

From GitHub:

 

Tentative Plan of the Course

The students will be asked to complete four assignments as part of their Certificate of Participation:

  1. problem set on nuclear physics -- due on Thursday, June 23rd, by the end of the day
  2. problem set on statistics -- due on Tuesday, June 28th
  3. experimental report -- due on Friday, July 1

 

Monday, June 20 -- Basics of Radiation

Radiation -- what is it?  Today we will start with a general discussion about radiation.

  • What is radiation?
  • How radiation affects us?
  • What is radiation dose?  What does it mean when we say that someone got a "high dose?"

Tuesday, June 21 -- Introduction to Nuclear Physics

  • Energy:  electron-Volt

  • Photons and Electrons

  • Photon interactions

    • Photoelectric effect

    • Compton Scattering

    • Pair production

  • Nuclear detection, the simplest device:  Geiger-Muller Counter

  • Shielding and attenuation:  how to calculate attenuation using mass attenuation coefficient

  • Hands on exercise:

    • Calculate attenuation using XCOM tables (see here)

    • …

 

Wednesday and Thursday, June 22 and 23 -- Statistics

Read Knoll Chapter 3 (~ 2hrs)

  • Random processes, independence

  • Binomial distribution

  • Poisson distribution

  • Gaussian statistics and Central Limit Theorem

  • Error propagation

  • Statistical tests:

    • Z-score

    • Chi2 test

  • Waiting time between two consecutive random events

  • Hands on exercises:

    • Use Z-score to calculate the probabilities of a) a political party winning the elections, and b) that a radioactive source is present

    • Apply the chi2 test for three data points and verify whether they come from the same process

    • calculate error

 

Friday, June 24 -- EE.01: basics of electronics, from resistors to High Voltage

During this lecture we'll do an overview of the basics of electricity.  We will use some material from 22.071, MIT course on analog electronics.

  • resistors as voltage dividers
  • inductors and capacitors
    • as integrators
    • as differentiators
    • 1st order circuits
  • transistors
    • as simple switches
    • as logic invertors
  • Diodes as simple "one way" trap-doors
  • boost converters -- DC to DC transformers, High Voltage
  •  

Time permitting...Scintillators

The scintillators are the most common type of a particle detector.  These work by converting the energy from the interaction into visible light.  The light is then collected by a photodetector which produces an electrical signal that can be digitized and acquired by your computer.  This then allows you to analyze the information and understand the parameters of the particle and interaction.

 

Monday, June 27 -- Detectors: Geiger Counters

Detectors -- Geiger counters as ionization chambers

  • Basics of electricity – how does the Geiger counter work?

Tuesday, June 28th -- Lab 0 (3 hrs)

During our first (zero-th) lab we will assemble the analog "core" of our Geiger counter.  

Wednesday, June 29th -- Lab 1 (3 hrs)

Now that we have a working Geiger counter we can instrument it with a small Arduino microcontroller, which will serve as the data acquisition (DAQ) of the system.  It will count and digitize the analog pulses and estimate the count rate and the dose rate.  It will also transfer data to the computer, allowing you to analyze it and observe some very interesting statistical phenomena

Thursday, June 30 -- Lab 2 (3 hrs)

Now that we have a working radiation detection system, we will perform experiments with radioactive sources to determine the effects of materials on radiation.

Exercises with the Geiger Counter...

  • Take two measurements:

    • Background

    • Source + background

    • Apply the Z-test to determine the probability that a source is present

  • Make multiple measurements of the background or source:

    • Apply the chi2 test to verify that the background is stable

    • Plot the waiting time between consecutive hits – is it exponential?

  • Test the statistical models and the Central Limit Theorem:

    • Plot the distribution of the 5-sec long measurements, such that you only get 1-2 counts – do you get a Poisson distribution?  

    • What if you do 1-min long measurements – do you get a Gaussian?

  • Measurements of attenuation using different targets

    • Measure with a source

    • Measure with a source and a target/absorber

    • Does the number of counts correspond to the predictions that are based on the mass attenuation coefficient?

Friday, July 1 -- Lab 3 (3 hrs)

This will be our computational lab, where we will analyze the data acquired on the previous days. 

APPLICATION:

Participation in this course is on a competitive basis.  To apply please go HERE. The deadline is June 10. The applicants will be informed about acceptance by June 16th.

 

Ideal background

The students should have 

  • Basic knowledge of statistics and probability
  • Basics of physics
  • Basic knowledge of electrical circuits (e.g.. transistors, capacitors, resistors)
  • Some coding and data analysis skills. Familiarity with python and the command line is a plus.
  • Proficiency in English

 

This week-long lab is modeled based on a similar one-week long course which was taught at MIT during the IAP of 2015 by Prof. Michael Short et al..  For more details about the MIT course see here.

Frequently Asked Questions

Q: I took the one-week long version of this back in January.  Am I eligible to apply?

A: Absolutely!  There are two caveats, however:

  • we will give some priority to the first time applicants
  • we ask that you bring your assembled Geiger counter with you, as we might simply not have enough parts

 

Q:  What should we bring?

A:  Three things: a laptop with python pre-installed and a command line; something to write on (which you'll do a lot); your enthusiasm! 

 

Goals of the Course

In this course the students will learn the basics of nuclear physics, radiation and nuclear detection.  The goals of the course are the following:

  • Learn basics of nuclear physics related to radiation

  • Learn introductory concepts on statistics that are relevant to nuclear detection

  • The basics behind the electronics of a Geiger-Muller counter (Geiger counter, for short)

  • Build a Geiger Counter

  • Make measurements with the counter

 

What is Radiation?  Where is it?

Radiation is everywhere in our surrounding world.  Most of the materials that we are surrounded with in our daily lives contain naturally occurring radioactive isotopes.  For example:

  • Bananas contain potassium (K).  Our own nerves use “potassium channels” to propagate the electrical signals that allow for our brain to work (and for this text to be written).  One of the isotopes of potassium is 40K, which is an unstable isotope with a half life of 1.251×109 years.  Yes, this means that our brain is radioactive!  

  • Most rock surrounding us naturally contains uranium (U) and thorium (Th).  Uranium and thorium undergo alpha-decay, which leads to other unstable isotopes.  These too decay, emitting alpha particles and gammas.  Granite in particular is quite rich with U and Th.

  • Many porous rocks, such as tuff (that many buildings in Armenia are built from), contain radon gas.  This gas, specifically 222Rn is a product of the decay of naturally occurring uranium.  Radon is an inert gas, which means that it easily goes through rock and escapes into the open air.  222Rn is radioactive, it decays by emitting an energetic alpha particle.  If you breathe in radon then its decay alphas will irradiate your lungs.  Too much of this will cause cancer.  In many countries increased cancer rates are attributed to accumulation of radon in basements.  This can be mitigated easily by venting the basements (most homes in Armenia unfortunately do not have this).

 

How is Radiation Used by Humanity?

Intense (unnaturally high) radiation can be harmful to us.  Why?  Because radiation causes ionization in the water, forming hydroxyl groups and other free radicals.  These bind to and break up DNA.  While the cell is extremely good at repairing radiation damage to its DNA (otherwise life wouldn’t exist!), sometimes  things go wrong and mutations occur.  These mutations sometimes accumulate, causing cancerous growth.  For this to happen you need large radiation doses.

However radiation can also be very helpful to humans if used ethically and correctly.  Here are a number of examples where radiation has significantly helped improve our lives:

  • X-ray is a form of radiation, which is used to image the human body to discover broken bones and cancerous tumors.

  • Computer Aided Tomography (CAT) uses X-ray to create a 3D image of your body to discover cancer and various life-threatening internal injuries.

  • Positron Emission Tomography (PET) uses radioactive isotopes to map out tumors in a cancer patient’s body, allowing doctors to detect and diagnose the cancer.

  • Gamma therapy uses beams of gammas to kill those cancerous tumors and thus save lives.

  • Physicists use various particle beams to study the fundamental laws of nature, thus improving our understanding of the world around us.

  • Archeologists use radiocarbon dating to determine the age of various archeological artifacts.  This is (in part) how we know Yerevan-Erebuni’s age.

  • Mars Perseverance Rover uses  a small “nuclear reactor,” a Radioisotope Thermal Generator as a source of its power.  This will allow Perseverance to study the surface of Mars, and possibly find life there.  Future space missions will continue to use radioactive sources for power, allowing them to explore the Solar system and beyond!

  • Radiation inside nuclear reactors, when used responsibly and competently,  produces electrical power which doesn’t contribute to global warming and keeps the environment clean.  Currently 30-40% of Armenia’s electricity comes from the Metsamor Nuclear Power Plant.  Every third light bulb in your home (on average) is powered by Metsamor.

 

Radiation is everywhere and you cannot escape it.  You can understand it however, and learn how to use it towards the welfare of humanity.  It is thus very important to understand radiation.  It means understanding the physics and the basic science behind radiation.  It also means developing an ability to measure and quantify radiation using specialized instruments and mathematical models.

In this rigorous, intense, yet enjoyable course students will

  • learn about the basics of Nuclear physics, Statistics, analog electronics
  • build their own DIY Geiger counter, using solder-less breadboards.  The Geiger counter will be instrumented with an Arduino, which will perform the initial data analysis and allow to transfer data to a computer.  In the end the students will get to keep their DIY Geiger counters, which they will then use to measure radiation in their immediate environment! 
  • use their Geiger counter to perform experiments involving radiation, where they will measure gamma counts and observe the effects of shielding on radiation