filling in the unspecified details of elegant-sounding descriptions of experimental methods.

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32 views

how can I detect cosmic muons from background?

Is there anything I should be careful with if I would like to detect muon at sea level? Noise background? Threshold? Even signals from other particle with stronger flux rate?
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0answers
13 views

Have the BaF2 scintillators a strong correlation with the alimentation current that cause the shifting of the centroids in the distribution?

In gamma gamma correlation I suspect the presence of systematic error maybe caused by a non optimal alimentation voltage according to someone there is a quadratic correlation between centroids ...
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0answers
27 views

What difference does it make if the turns in a tesla coil overlap?

Would a tesla coil in which the primary coil is made by overlapping the turns of the wire work?
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1answer
22 views

Pound-Drever-Hall frequency stabilisation technique

I am having some difficulty understanding the Pound-Drever-Hall frequency stabilisation technique, when locking a laser to a stable cavity. As far as I understand: We emit the laser frequency, f0....
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0answers
28 views

Galileo's pendulum and any references

In some texts about the simple pendulum we use to see references about some "experiments" Galileo Galilei did realize and whereby he found some important results, including that the period of the ...
2
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1answer
46 views

High $p_T$ and high $Q^2$ in deep inelastic hadronic collisions

When reading about high energy collisions (for example proton-proton collisions at LHC), I always find the relation $Q\sim p_T$, which, for me, is hard to demonstrate. Moreover, I found statements ...
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1answer
34 views

Is it possible to measure the resistivity of something using A.C. Current and a capacitor?

I've read that A.C. current "passes" through a capacitor. Is it possible to use this and measure the resistivity of the medium between the plates? Any sources or links would be appreciated.
3
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1answer
38 views

Why does a CfBe neutron source not exist?

Sources such as AmBe take advantage of Beryllium's $(\alpha,n)$ process to produce high energy neutrons. Sources such as Cf utilize spontaneous fission. Why not combine the two? Such a source would ...
2
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2answers
71 views

Muon lifetime determination

My colleagues and I performed several experiments to determine the lifetime of the muon (from secondary cosmic rays) using scintillator detectors coupled to multi-channel analysers. The results ...
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14 views

Measurement of Quantum Hall Effect

I'm somewhat confused about the original measurement of the QHE in a Si-MOSFET, which might stem from my not understanding MOSFETs very well. In their measurement, von Klitzing et al. measure the ...
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2answers
138 views

Why do we learn only two computations, cross sections and decay rates, in such a fundamental theory as QFT?

When I learned Newtonian mechanics I found a vast variety of computations that I could do and that was so interesting. And it was so when I learned Maxwell theory. When I started learning QFT I hoped ...
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1answer
34 views

Can vernier scale ratio be less than 1?

I came across a question (See Image) that states about two vernier scales The first vernier scale is the top-most figure in the image: It has 10 vernier scale division equal to 9 main scale division ...
0
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1answer
47 views

why am i getting lower mass after melting iron dust?

I've been trying to melt iron dust for a long time but after melting I lose a lot of mass. Any idea what is causing this? I've used gas and electrical arc to melt the dust.
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1answer
51 views

Optical Retroreflectors: How Are the Faces So Accurately Righted?

This question is about Optical Retroreflectors (corner cubes) and how the extreme precision in their manufacturing is achieved. I suspect there is interesting basic physics involved, which is why the ...
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4answers
970 views

Glass pipe cutting

I want to know how to quickly create the straightest possible breaks in glass pipes I apologise if this is only borderline suitable for a physics forum - I just hope experts with a lot of experience ...
0
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1answer
47 views

Propagation error for a third grade equation

I am trying to find the value for the roots$\pm$error for a set of experimental data. The function that fit the best is $$\epsilon(t)=a+bt+ct^2+dt^3.$$ Which is the best way to calculate the roots $\...
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2answers
55 views

Creating nanosecond pulses from a CW laser source

Experimental setup question. If anyone aware of a technique to create pulses of several nanoseconds at a around 10Hz repetition rate from a CW laser source?
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1answer
29 views

How to make a monocrystalline silicon seed

I do understand that you can grow monocrystalline silicon from an initial seed but I'm lost in a chicken versus egg situation where I don't understand how you can get the seed if the only way to make ...
2
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1answer
57 views

What is the minimum sample sizes to show the error bar in an experiment?

In scientific experiment, people often try to show an error bar based on the standard deviation around a mean (average) value. My question is twofold: How to estimate the minimum but adequate ...
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2answers
270 views

How can we test relationship between frequency and peak current of an alternating current?

It has been suggested to me that $$\frac{V_{peak}^2}{I_{peak}^2}=R^2_{coil}+4\pi^2f^2L^2$$ where $L$ is a constant and $f$ is the frequency of AC. As a high school student I don't understand how can ...
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1answer
84 views

Measuring very long half lives accurately

There are already some questions about long half life times for radioactive elements, explaining how to calculate the half life time. Now I am wondering: When you have some radioactive material and ...
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3answers
319 views

Measuring the effective mass

Intro: To avoid any terminology confusion, this is asked in the context of Solid State Physics and semiconductors. The canonical definition given for the effective mass is that it is related to the ...
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0answers
37 views

How are optical lattices created, and how big can they be?

I am asking about the basic concept and the schematics of the laser configuration. How are atoms forced to stay in optical lattices? What lasers (power, wavelength, etc.) are used, and how are they ...
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0answers
10 views

Anoxic sample containers

I am preparing pure Si samples, etching the oxide layer, in an argon glovebox, and I have to transfer them to the AFM. We don't have any sample containers in the lab, so I have to buy some. I wasn't ...
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0answers
20 views

What is needed to be taken into consideration when measuring torque in dynamic mode?

Let's consider a DG generator connected with a hydraulic turbine through a shaft. To the stator of the generator it's attached a arm connected to a load cell. The load cell is measuring the force that ...
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0answers
25 views

Sine wave in my residuals graph [closed]

We had a physics experiment where we should have had a linear relation between 2 measured values, we got a pretty good fir however our residuals plot has a kind of a sine wave behaviour. We were told ...
3
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1answer
71 views

Why does one use different materials for cathode and anode in the photoelectric effect experiment

All photoeletric lab experiments I have seen so far have a setup where you have different materials for cathode and anode. However this raises some experimental difficulties since you have to take ...
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1answer
55 views

Are residuals supposed to have error bars?

Hopefully I'm asking this in the correct section. So I've got a graph with a linear trend of data and a best fit line plotted. The data points on the main graph obviously each have their own error ...
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1answer
39 views

What is an absolute frequency reference (Frequency combs)?

So I am currently studying for my bachelors thesis which is all about frequency combs. I am reading a lot of articles about them but I just keep coming across things that the people who wrote the ...
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1answer
55 views

Why is 2-terminal sensing less accurate than 4-terminal sensing if the internal resistance of leads is known?

I have a pretty good understanding of 2-terminal vs. 4-terminal (kelvin) sensing measurements. I understand that in the 4-terminal measurement, current is supplied by 2 terminals that are separate ...
5
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2answers
386 views

Einstein's original papers predicting gravitational waves? [closed]

I came across the original handwritten papers in which Einstein predicted gravitational waves1: and since LIGO announced they've detected a signal confirming the predictions I was wondering if ...
4
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1answer
33 views

What's the difference in the film between sputtering deposition and an ebeam evaporator?

I know the differences between the two deposition techniques, but what about the difference in the properties of the resulting films? All things being equal (such as substrate temperature), would ...
6
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1answer
2k views

Liquid nitrogen and liquid helium

In cryogenics, liquid nitrogen and liquid helium are often used as coolants. Other than their low boiling point of 77K and 4.2K respectively, what properties make them suitable as coolants? Are there ...
25
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0answers
847 views

Are the fast axes on Thorlabs quarter-waveplates mislabeled?

Some members of my lab are performing a polarization-sensitive experiment where they need to use a quarter-waveplate (QWP) with the fast axis in a specific direction. In the process of carefully ...
3
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1answer
39 views

Machine readable database of gamma lines

Friends of mine did a lab experiment where they recorded $\gamma$-spectra in the range from 0 to 1500 keV with a soil sample. The data contains some background and a couple sharp peaks at different ...
3
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2answers
77 views

How to measure transverse current-current correlation at arbitrary wave vector and frequency

Let $\hat J^{\mu}(t,\boldsymbol r) \equiv (c \hat \rho(t,\boldsymbol r), \hat{\boldsymbol J}(t,\boldsymbol r))$ be the density-current operator at spacetime coordinate $(t,\boldsymbol r)$, in the ...
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3answers
29 views

Measuring Activity

The formula for Activity of a radioactive substance is $ \frac{dN}{dt}=A=λN $. If we have an initial number $N(0)$ of some Radionuclide, which has a halflife of, say, 12 hours, is there any ...
1
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1answer
104 views

Double slit experiment mechanism

Can someone explain the mechanism that sets in motion the electrons in the experiment? Is it an electro-magnetic force? If so, I think it's not right to describe the motion of the electron as a '...
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2answers
35 views

Gamma spectroscopy - Fitted Singlet

I'm using some gamma acquisition and analysis software. When I ask the software to do some sort of Nuclide Identification, almost every single peak in the generated output is marked with "F". ...
16
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4answers
11k views

How to prolong life of liquid nitrogen in hosehold vacuum flask?

I need to do some work with liquid nitrogen at home. The main question is how to store it without buying huge vacuum flask specifically for liquid nitrogen. I've tried to use usual steel household ...
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0answers
26 views

Procedure for wrapping a superconducting coil around a cylindrical shell?

I don't know if experimental physics questions are allowed on this site - please direct me to the proper SE if it doesn't belong here. I need to wrap a few layers of superconducting wire (~80 ...
0
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1answer
36 views

measure barometric pressure using boiling water

I have set a cup of water in a bell jar, with a thermometer. I am able to lower the pressure until the water boils and I am able to measure the temperature of the water simultaneously. I then looked ...
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0answers
19 views

Interferences while using two ToF cameras

Im using two time-of-flight (ToF) cameras, a DS325 from SoftKinetic and a Creative Senz3D, at the same time with the DepthSense-SDK and the Point-Cloud-Library (on Ubuntu 15.04). But I got strong ...
0
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1answer
41 views

prototyping a cyclotron , a charging problem

I'd like to model a cyclotron but not with subatomic particles but with a small metallic ball but the problem is i need to charge the metallic ball with certain amount of charge and i must know it to ...
12
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2answers
424 views

Are there any inventions/applications in our world based on QFT?

Are there nowadays any actual devices or experimental applications which are based on the quantum field theory and if so, how are they related to QFT? I could not find any similar question besides ...
4
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2answers
133 views

Is circular masking a laser beam an acceptable way to get the beam diameter you require?

I am wondering what are the down sides to just masking a laser to get the beam diameter you require? For example if you have a collimated eliptical beam of say 2mm width and 4mm height, but you ...
2
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0answers
24 views

Creating a structural dynamic model using only modal test data

Short version: Suppose I excite a vibrational response in some structure and measure its mode shapes and natural frequencies. Is it possible to create a structural dynamic model of the structure ...
0
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1answer
208 views

X-ray diffraction on thin film

As far as I am concerned, when we perform an X-ray diffraction experiment using a Bragg-Brentano diffractometer using the "powder method" we have that the scattering pattern depends on only one angle ...
2
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0answers
40 views

Determining the spatial imaging resolution based on a pinhole diffraction pattern

I aimed a 780 nm/1mW laser at a 1μm pinhole and took a picture of it using a lens and a CCD camera. The magnification of my imaging system is ~25 times. I wrote some code that takes the image of the ...