User talk:Kmajahid63
From MariachiWiki
We did the popcorn lab today, where we observed the rate of the poppings over certain time intervals. What was most interesting was how closely the microphone measured the poppings. The confusing part of the lab was deciding if the waves on the graph were actual measurements of the poppings or they were miscellaneous noises, such as the fan or people talking in the room, otherwise it was pretty straightforward.
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March 30, 2006
Today we spent the whole class time coming up with ideas for the experiments that we are going to be conducting for the rest of this session. Basically, we have only done one experiment (the popcorn lab), and had no idea of what we were going to do. Coming up with new ideas of what we could experiment with was the challenging moment of the day. It was really hard to get motivated, but i really was interested in if something could change the speed of the cosmic rays or how we could block or slow down the cosmic rays from hitting the particle detector, which was the lightbulb moment of the day. Our three experiments that we came up with are : determining the direction of the cosmic rays, determining the speed of cosmic rays, and what cosmic rays can pass through?
April 6, 2006
The lecture by Angela V. Olinto, from the University of Chicago was about the Ultra High Energy Cosmic Rays (UHECR). She discussed that the UHECR's could possibly be from blackholes, gamma ray bursts, young neutron stars or from fast magnetic EG. Her project, the Pierre Auger Observatory, whose goal is to determine the origin of UHECR's. She also discussed the possible sources of cosmic rays : extragalatic, galatic, DM Halo, or space and also what the sources are:
shocks, jets, injection spectrum, acceleration or decay. The composition of UHECR's could be from protons, mixed nuclei, gammas, or neutrinos. In her project she observes spectrum, composition, anistropies in the sky, protons and neutrons. In the cosmic ray spectrum there are twelve orders of magnitude and in 1938, Pierre Auger discovered the Extensive Air Showers (EAS).
In her lecture, Angela also discussed another detector, KASCADE or Karishurke Shower Core and Array Detector, that take direct and indirect measurements. In this project, there are large uncertainties in the Monte Carlo simulated hadronic interaction, so they get help from Terrestial Accelerator Experiments. In her project, to measure the anisotropies, the cosmic rays arrival directions are isotropic. She described the cosmic rays as charges (protons and neutrons) that are deflected by magnetic fields. Cosmic rays with energy of less than 10^19 eV have more deflection, while rays with energy more than 10^19 have no deflection, thus gamma rays come straight to the Milky Way galaxy and are not deflected.
UHECR are rays with energy from 10^18 eV to greater than 10^20 eV. They are the highest energy particles ever observed through air showers. The GZK Feature of cosmic rays depends on the maximum energy, injection spectrum, composition, magnetic fields, and background radiation. The high energy proton sees cosmic microwave background as High Energy Gamma Rays. She also measures the composition by measuring angle of shower from the impact point because it is different for protons, mixed composition, and pure Fe nuclei. The present experiments that she's doing are 10^3 km^2 sryr, but they have to reach greater than 10^4 to 10^5 km^2sryr. For this, she has put 2 Ground Array with Flourescene detectors and hybrid detectors, that are 30 times the Agasa detectors. These 1600 detectors are places over 3000km^2 in Argentina. Currently, they are still placing the detectors all over the selected area and will be completed soon. Her lecture did explain and clarify some questions we had about cosmic rays, but some parts of it was confusing, in that she was using the cosmic ray jargon that we completely did not understand.
Oscilloscope
An oscilloscope measures the time it take for cosmic rays to pass through both of the scintillators. The discriminator detects the electrical pulse . The logic unit traces a graph of the signal on the screen and creates a square wave.
Cosmic rays come from above because they are coming from outside the galaxy. We could measure this by putting the two scintillator vertically on top of the each and then horizontally, whichever has the highest number of coincidences will be the direction; if it's higher vertically then they are coming from above, if not then they are from below.
April 17, 2006
We did the experiment to find the speed of cosmic rays. We used two scintillators and changed the distance. The distance between the two waves that showed up on the oscilloscope to determine the time the cosmic rays took to go over that distance. The slope of distance vs velocity gives the velocity. The challenging part of the lab was determining the distance between the two waves because the wave from the second scintillator flashed a couple of time so it was hard to determine how much it had moved over relative to the first wave. The lightbulb moment was when it got easier to detect the second wave after a while, to get the time for that distance.
April 19, 2006
We measured how different materials affect cosmic rays, whether they slow them down or remain the same. We used wood, aluminum, lead bricks, and cosmic chris to see how cosmic rays are affected. The challenge moment of this lab was determining how long it took for the cosmic chris scintillator to reach 999 counts. The lightbulb moment was when we determined that for the lead brick we had to have a separate control because the scintillators were in a perpendicular position the control also had to be exactly in the same position.
Final Blog:
Brainstorm Redux: We did the experiment where we put materials between the scintillators, I actually would like to know that what would happen if we put a person between them. It sounds weird but it's interesting and I would like to explore that and see how it affects the person too.
Blog: No offense to anyone here, but I thought the method for this class, coming up with our experiments without knowing what the oscilloscope does and what cosmic rays are, did not work for me. I know in science that we're trying to find out something that someone else hasn't, so we exactly don't have a guideline, but we didn't have enough background and that's what made it hard.
Challinging moment: coming up with the experiments Light bulb moment: understanding finally what an oscilloscope does
