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

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26 views

Collection Efficiency of Photon

I am currently reading this paper: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.116802#references In the second column of text in page 2, the author makes various claims about the ...
4
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1answer
76 views

How do you measure a particle's postion or momentum?

This question is about the Uncertainty Principle $$\sigma_x \sigma_p ~\ge ~\frac{\hbar}{2}.$$ Looking at the maths, I understant why the uncertainty in the poistion increases as the uncertainty in ...
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2answers
52 views

How do you know which atoms are in a specific piece of matter?

If you have a piece of matter in front of you, how can you know of which atoms it consists? And starting from nothing, how can I discover all the elements (or just a lot of them) of the periodic ...
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1answer
45 views

Dead time in data acquisition

I am creating a data acquisition software, based on Sparrow's Kmax. There I would like to add a feature that will show the system's dead time. I have already a text field that shows the real time and ...
3
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1answer
39 views

Why apply voltage on an Si detector only on atmosphere or high vacuum

The general instruction when using a silicon detector is to either apply voltage only in atmospheric pressure or in high vacuum. Not in between! I can't find a physical answer to it. Why is it so ...
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101 views

A vertical variation of modern versions of Michelson-Morley

For almost a year now, I have been in the uncomfortable position of having an idea. However, there is one nice thing about this idea. It makes a concrete, exact and relatively easy to test physical ...
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0answers
34 views

Alternative ways to take particle tracks photographs in a cloud chamber

I know that the most common type of particle tracks photography is in photographic plates, but i'm using a cloud chamber and I would like to know if there are alternative ways to take photographs of ...
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3answers
81 views

Error propagation estimations for sine and cosine

My lab manual gives this: $B$ is a function of $A$, Greek are uncertainties... $$B + \beta = \sin(A + \alpha) = \sin(A)\cdot\cos(\alpha) + \sin(\alpha)\cdot\cos(A)$$ --> because $\alpha$ is ...
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1answer
79 views

How is a standard unit divided into equally smaller or fractional units physically/experimentally?

Consider the standard unit of length: meter. How was it divided into decimeter, centimeter, millimeter, etc. when there were no shorter lengths than the standard ? What is the physical/experimental ...
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1answer
155 views

How would a physicist measure temperature of molten metals in 1850-1920s?

How would a physicist measure temperature of molten metals in 1850-1920s? What equipment would be used?
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41 views

Which microscopy technique is for wet condition? [closed]

I am searching for a microscopy technique in wet conditions. It must be possible to see through the specimen. ESEM is good but can't see through. TEM needs high vacuum which will boil away water. The ...
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2answers
54 views

How to realize long-range interaction of colds atom in an optical lattice?

In the Bose-Hubbard model of cold atoms in an optical lattice, we consider only the short-range interaction or on-site interaction. Is it possible to realize long-range interaction similar to Coulomb ...
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2answers
135 views

How to determine if a optical system is afocal?

I have to come up with a method to measure the focal length of a concave lens that's not in my lab guidebook. So I decide that I will build an afocal system with a convex lens and a concave lens and ...
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4answers
881 views

Double Slit Experiment: How do scientists ensure that there's only one photon?

Many documentaries regarding the double slit experiment state that they only send a single photon through the slit. How is that achieved and can it really be ensured that it is a single photon?
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43 views

Where can I find a device or how can I make a device that measures only Alpha particles?

Are there special muller tubes that only measure alpha for example?
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1answer
86 views

Self-sustained vs. non-self-sustained discharge systems

I don't quite understand what a self-sustained discharge is. I figure it means that the processes involved are self supporting and generate themselves, so that I don't have to put energy into the ...
8
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1answer
113 views

How to distinguish high-energetic muons and electrons in the CMS and ATLAS muon detectors?

At a typical energy of about 100 GeV, a muon has a Lorentz factor of about 1000, an electron about 200.000. The flight time to the detector should be around 30 ns (assuming d= 10m from the collision ...
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1answer
243 views

time constant for typical fluorescent lights

For a typical flourescent light available in the United States on a a standard 120V 60Hz line, is there information available on the decay time of the light? For example, if I am running the light a ...
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2answers
112 views

Measuring the velocity of a pendulum using the width of the bob

I did an experiment on pendulum motion and in the method it says use the following equation to measure the velocity of the pendulum: $$v=\frac{W}{t}$$ where $W$ is the width of the pendulum bob and t ...
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3answers
2k 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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2answers
195 views

Are there solid materials with controllable porosity?

In analogy to piezoelectric materials, where the application of an electrical field creates mechanical deformation in the material, I have the following question. Are there solid materials whose ...
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0answers
90 views

Measuring a quantity using two measuring devices

I would like to ask how I can reduce uncertainty by designing an experiment. I need to measure a quantity( say speed, in m/s). I have to calibrate the device and then move the device to measure ...
5
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1answer
380 views

Atoms' excitation energies as derived from Frank-Hertz experiment data

I'm analyzing the experimental data obtained during Frank-Hertz experiment (conducted with Hg atoms): Accelerating voltage values were multiplied by 0.1 during measurement (i.e. the mean value of ...
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1answer
176 views

Frank-Hertz experiment setup

The usual schematic representing the setup of Frank-Hertz experiment is the following: However, sometimes, you can see a bit different schematic: My question is: what function does $V_{G_1K}$ ...
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3answers
378 views

How should I clean a part before installing it in a vacuum system?

What are proven procedures for preparing a part that comes fresh out of the workshop for ultra-high vacuum (UHV) and extremely-high vacuum (XUV)?
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0answers
446 views

Methods to Stabilize and Maintain Extremely Low Humidity in a Lab Environment

My atomic physics lab is in a building that experiences huge swings in humidity levels during the year due to the monsoon season Our building provides temperature, but not humidity control. Using ...
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1answer
64 views

Uncertainty in approximated relation

I'll give directly an example to fix the ideas. Suppose that you're studying the acceleration of a system of masses that depends from the number $n$ of masses $m$ by the following relation: ...
2
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1answer
68 views

Creating a stream of single file atoms

How do you go about creating a stream of single file atoms? The aim is to fire a stream of single file atoms (hydrogen, helium) down a vacuum and detect there arrival on the opposite end. Any ...
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1answer
87 views

Galaxy Kinematic Fitting: How to deal with Point Spread Function (PSF)

The past few months I have been studying astronomy and Integral Field Spectroscopy (IFS). What I want to do is to fit a galaxy kinematic model to data (ie: estimate the model parameters that give the ...
3
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1answer
61 views

Time of Measurement Vs Number of Measurements

Let's say that an experiment has to determine the number of cosmic muon at sea level. The appropriate equipment is ready to measure the counting rate. I can think of two ways Count for 10 minutes, ...
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2answers
385 views

Optics alignment of a confocal scanning microscope

I am facing a challenge in my project regarding optical alignment. See the figure: The challenge is with the vertical optical system alignment. I considered placing a mirror and check back if the ...
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1answer
398 views

Mechanical Equivalent of Heat

Recently I have been looking up James Joule's experiment regarding the mechanical equivalent of heat. After viewing some drawings of the apparatus, I assumed that the lines holding the weights would ...
4
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1answer
167 views

How important is it, really, to clean vacuum parts?

In every lab I've seen, people are quite meticulous about cleaning parts that are to be used in ultrahigh vacuum, as well as the components of the chamber itself. The parts may be put in an ultrasonic ...
3
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0answers
156 views

Production vs. Collection, and Contaminants vs. Depositions, what might be missing in cold fusion research

I though cold fusion and LENR were discredited, but just a few days ago I found out that NASA is claiming LENR is real. So I thought if they're detecting something, what could it be, and why wasn't it ...
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1answer
181 views

Experimental measurement of volumetric flow rate

The other day I with my team had to measure the volumetric flow rate through a pipe only using a 2000 mm$^3$ volumetric flask and a chronometer. The end of the pipe discharged to the atmosphere. As we ...
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2answers
2k views

Multiple measurements of the same quantity - combining uncertainties

I have a number of measurements of the same quantity (in this case, the speed of sound in a material). Each of these measurements has their own uncertainty. $$ v_{1} \pm \Delta v_{1} $$ $$ v_{2} \pm ...
3
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1answer
170 views

What algorithms are used for track reconstruction in cloud chambers?

In particular I'm interested in any algorithms that can separate multiple tracks from one another reliably.
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1answer
621 views

Experiment to measure initial speed of high speed tennis ball?

I want to devise a way to measure the initial speed of a tennis ball fired from a tennis ball cannon, but without using any speed-measuring devices. Just plan distance-measuring and physics formulas. ...
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3answers
341 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 ...
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2answers
142 views

Layman's method to sharpen a wire (STM-tip)

We use a platinum-irididum wire to fabricate our STM tips. And by "fabricate" I mean to cut it with really sharp pliers or scissors. Sometimes we get good tips but most of the time they are not usable ...
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1answer
79 views

How can I cheat an XRD sample (~10 mg) from a total 1g required? How can I use for the background.

How much can affect (in terms of hump) my X-ray diffraction pattern the "amorphous" glass or maybe someone can suggest me other material to compensate for the small amount of the sample. Note: my ...
5
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1answer
133 views

Real World measurements related to phonon dispersion

I hope no one objects to the style of this question. Let me explain my motives in asking the question first. Condensed matter physics is one of the most beautiful subjects around. But those who are ...
3
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2answers
184 views

Do I need to have an airtight container to siphon boiling water?

I'm attempting to siphon boiling water into another container for a school project. I have researched the physics of a siphon but I can't seem to make my boiling water siphon out of its initial pot. ...
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1answer
182 views

Repulsive Magnetic Hammering Experiment

I have been thinking about something thing... I want to attach four or any number of magnets with arms to an axle.. Blue dots be magnets. Its is not a wheel configuration, all arms can move ...
4
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1answer
632 views

Ways to create controlled small bubbles in water within plastic tubing

What is a practical way in an engineering or physics laboratory to create bubbles of a specified size in water within plastic tubing? The tubing is a few mm inner diameter. We'd like to make bubbles ...
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1answer
688 views

How do you calculate the equivalent absorbed radiation dose from activity, type of emission, and the energy of the emission?

I have a sample of U-238 of which my Geiger counter detects beta activity at 700 events per second. Based on the counter's efficiency of 98.6% for U-238, the activity would be about 710 becquerels, I ...
5
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2answers
282 views

statistics for photon counts in photomultiplier

It seems that a common statistical model for the count numbers of a photomultiplier is a Poisson distribution whose parameter $\lambda$ equals to the square-root of the number of counts.(e.g. ...
2
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1answer
199 views

Difference between Diamond anvil cell and Bridgman cell

In high pressure physics what is the difference between diamond anvil cells (DAC) and Bridgman cells? My understanding is that they are both forms of anvil cell but in the scientific literature I'm ...
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1answer
41 views

What is pulsed neutron diffraction?

I have tried a google search and checked my condensed matter books but I can't find out what pulsed neutron diffraction is and how it differs from inelastic neutron scattering.
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1answer
232 views

Rutherford's Gold Foil Experiment

Can anybody explain how Rutherford bombarded a 0.0004 cm thick gold foil? How did he put it in a photographic sheet? Wasn't the foil too thin to be held? How did he know that the atoms were deflected ...