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| visits | member for | 2 years |
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| stats | profile views | 48 |
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May 18 |
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Interpreting the results Oh, so basically I always have 10$\mu s$ because of my TDC, and always have to scale my bins accordingly. But that will also give me some change in mean life of muon. If I put 10 bins, I get $<t>=2.775193$ $\mu s$, for 20 bins $<t>=2.496124$ $\mu s$, and for 100 bins $<t>=2.297360$ $\mu s$. How to find the optimal bin division? By guessing? :\ |
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May 17 |
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Interpreting the results Well it's just the count of muons that decayed within the scintillation detector in a period of the measurement. Now I don't really know how long did they left it running, since we only set it up as a lab exercise, and then they sent us the data. |
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May 17 |
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Interpreting the results My first chanel was like 40000, and last was 30 or so, but in between I had many 0, some 1 and 2. My professor said something about that first being the noise, and that I should disregard that. |
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May 17 |
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Interpreting the results So basically I would have to do something like t=10\mu s/8190 *n, where n is my bin number, if I got it right? That would be my 'gauge' sort of? Oh, and I was aware of the Poisson statistics, I planned to put error bars according to the count. If in first bin I have 150 events, then the error is $\sqrt{N}$, right? |
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Mar 10 |
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More points vs. precision I've done my measurements so the banana one is out, but I'll use your advice on those 4 points :) Thank you. I must say the banana one is really interesting :D |
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Mar 10 |
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More points vs. precision Oh, so, out of those 4 most intensive peaks, I should just use the bigges one, and say that it's the most intensive one (356 keV). Because I was thinking I could use those 4, since I can see a Compton edge at around 230th channel. |
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Mar 10 |
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More points vs. precision I put spectra data into Origin, and with data picker I just saw the channel I have the biggest peak on. I have 2 unknown sources (my guess is Th and U), and I have Ortec HPGe (rather old setup, nothing fancy). And I can identify Compton edges, but I have no theoretical/experimental data to compare my findings to :\ |
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Mar 10 |
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More points vs. precision I'm not sure I understood this: "What tool are you using that isn't letting you know about these problems?" :\ You mean, what program I'm using to record this or with which I'm processing my data? Oh I'll show Ba spectrum, which is kinda... difficult to interpret for me, that's the point why I asked the question :D I'm not 100% sure to which peak I need to attribute the energies :\ |
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Feb 22 |
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Diffeomorphisms and boundary conditions Hi, I'm trying to solve the problem you've stated, in your exercises, but I don't think I am doing this right. First, I don't seem to know where that $O(1)$ comes from in calculating the Lie derivative of the ++ component. Sure, I get where I get the $2g_{+-}\partial_+\xi^-$, that's straight forward, but then the $O(1)$ appears :\ Plus if I differentiate the $\xi^-$ wouldn't I get third derivative of $\varepsilon^+(x^+)$? Is there any literature or solved exercises I could see? That would help a lot... |
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Feb 16 |
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Creation and Annihilation operator Well by redefining the system with the creation and annihilation operator, you get to work with operators, so this is just the application of these rules on the above equation. See for instance this: en.wikipedia.org/wiki/Quantum_harmonic_oscillator I really don't see the real issue here (or I am not understanding what's troubling you :( ) |
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Feb 7 |
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Diffeomorphisms and boundary conditions Thank you for the detailed answer! :) I will work on this problem on my master thesis, and I tried to get the results of $AdS_3$ metric, that I've found on the web by applying the Brown-Henneaux boundary conditions, but I didn't have much time to go through with it, since I had other exams and I was working on a seminar, but I'll definitely try to work that out before starting with the NHEK. Thanks again for guiding me in the right direction :) |
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Feb 2 |
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Diffeomorphisms and boundary conditions I posted that on math.stackexchange because I hadn't find an answer here... |
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Jan 28 |
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Help with the understanding of boundary conditions on $AdS_3$ Related question, but I cannot seem to check if it's the correct way of solving this :\ |
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Jan 27 |
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Dark energy before radiation or after? Care to give some good links? |
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Jan 27 |
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Dark energy before radiation or after? So basically the inflation is due to dark energy? And therefore dark energy was there before the radiation era? |
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Jan 23 |
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Covariant derivative with upper index Hmmm, thanks, that could help, I hope :D |
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Jan 23 |
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Covariant derivative with upper index Hmm, but what if I have $D_\mu h^{\sigma\nu}$, and I need to lower the indices of the $h^{\sigma\nu}$, does that mean, that I can put the g's that will lower the indices of h outside also? |
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Jan 22 |
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Covariant derivative with upper index Thanks for the clarification, I'll try to make sth out of this expression :D |
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Jan 22 |
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Covariant derivative with upper index "Typically, it also implies that any derivatives appearing are with respect to covariant components instead of contravariant." What if I have mixed terms inside? I mean, in the expression I also have scalars, covariant vectors, contravariant vectors, covariant and contravariant tensors... |
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Jan 17 |
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Please recommend a physics problems book similar to Demidovich If you solve Irodov, you'll probably be able to solve anything else in the 'general physics' sense ;) So I agree with ramanujan_diracs choice :) |
