Use this tag for questions pertaining to the limits, management, and operation of equipment necessary to experimental physics. This tag is not intended for "does this thing I heard about actually work" type questions.

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15
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1answer
440 views

Are the Voyager probes still sending us a signal ?

This article reported today, a finding from one of the voyager probes. It talks about magnetic structures at the (far) outer edge of our solar system. Does that mean we're still able to pick up a ...
14
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3answers
214 views

Why and how will we be able to image extraterrestrial planets in the next two decades?

According to a recently published article, a well-established Cambridge astrophysicist stated that: the ÔÇťorigin of life, where it exists, and whether aliens exist, is going to be crucial over ...
10
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2answers
2k 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 ...
7
votes
1answer
80 views

How strong must a signal be at the edge of the Solar System to penetrate into the Sytem?

A sort-of follow-up to Are the Voyager probes still sending us a signal ? Still following on the news report referenced in the above question, this report indicates further magnetic surprises at, or ...
5
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2answers
347 views

Accuracy of various optical instruments

I understand that this may not be the type of question allowed here, but I'm not sure. Feel free to close this if you feel that it shouldn't be here I'm planning on carrying out a certain set of ...
5
votes
1answer
412 views

How does the Double Slit Experiment work in detail?

What is the best detailed description/visualisation of the experiment available? Describing what is actually measured, how the data is analysed, correlated and interpreted when for example large ...
5
votes
1answer
252 views

How can I make a dry dilution refrigerator quiet?

The pulse tubes are really loud. We've wrapped the helium lines in sound absorbing foam, and we have a cage around the top of the cryostat also lined with foam, but it's still pretty loud. To make ...
5
votes
1answer
1k views

Are CCDs approaching the sensitivity of photomultiplier tubes?

I still see photomultiplier tubes (PMT) used for even benchtop spectroscopy experiments. How much more sensitive are they to CCDs? I found a post which claims about 1.5 x more sensitivity for PMTs,...
5
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0answers
308 views

Mirrors and light beam divergence technology limits

There are many applications for orbital space mirrors in astronomy (better telescopes) and space propulsion (solar power for deep space probes), but this is limited by the minimum beam divergence ...
4
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2answers
349 views

Catching/harvesting neutrons

This question has several parts. How does modern science catch free neutrons that are just floating around? Is there anyway to "pull" a neutron off any atom that does not involve our current ...
4
votes
2answers
4k views

Could we use particle colliders as fusion generators?

So I know the basic gist is that fusion power's main issue is sustaining the fusion. I also know that there are two methods. The Torus method and the laser method. The torus magnetically contains ...
4
votes
1answer
149 views

Are old fashion photomultipliers used in LHC experiments?

Are any photomultipliers used in any of LHC detectors? Or are only semiconductor devices used? If yes, then where?
4
votes
1answer
337 views

How can some optical microscopes measure height differences of different sample planes with nanometer accuracy?

I could use last week an optical microscope, didn't seem special in any way, 50x magnification, image viewable per a CCD camera on a computer screen besides through the ocular. But the software of ...
4
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0answers
58 views

Entanglement g-2-experiment - Which components do I need?

I would like to measure whether my source emits entangled photon pairs. To that order I want to build a g-2-experiment, which measures photon coincidence counts as a function of time delay between ...
3
votes
2answers
54 views

What is crater's influence on laser ablation?

In many laser ablation experiments (especially Pulsed Laser Deposition), target is moving to avoid crater formation. But I can't find any source that says why it is needed to avoid it. So why is ...
3
votes
1answer
1k views

What are the purposes of slits inside a spectrometer (Czerny-Turner)?

I am building a Raman spectrometer with a Czerny Turner configuration (with RamanPi). Why does the light source (A) appear to be converging into the entrance slit (B)? When a sample is excited by a ...
3
votes
1answer
167 views

Low-cost 532nm DPSS laser modulation

Could anyone suggest modern means of modulating 100mW CW 532nm DPSS laser? This should be low-cost(<50$) in high volume. Frequency bandwidth is 10Mhz, so modulation of pumping diode would ...
3
votes
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
votes
2answers
460 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 ...
3
votes
0answers
54 views

Energy dependence of integrating dosimeters

The graph shows the relative response of a dosimeter at different energies, normalized to 1.25 MeV Co-60 gamma rays. Curve A is the graph of the equation $$ \frac{\bigg(\frac{r}{X}\bigg)_\bar{E}}{\...
2
votes
1answer
403 views

Is there a significant possibility of the LHC missing “exotic” particles or events?

In his popsci book, "Particle at the end of the universe", Sean Carroll says that the LHC, due to it's sheer information gathering capability, necessarily needs to completely discard most of the data ...
2
votes
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 ...
2
votes
1answer
2k views

Inductor with controlled temperature coefficient

Let's assume we have an air-spaced inductor made of copper wire. As temperature changes, due to thermal expansion of physical dimensions of the coil, its inductance changes too. 1) Is there a way to ...
2
votes
1answer
41 views

How deep within the sample can the DOS(density of states) be detected by STM(scanning tunnel microscope)?

Using STM equipment, we can get the LDOS(local density of states) on the surface of a sample. I want to know whether the LDOS within the sample(not surface) can be detected by STM. what is the ...
2
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0answers
80 views

The stunning footage of neutral currents, first observation of a neutrino: Knowledge needed

First of all, this question is purely motivated by curiosity. I call upon the community's knowledge on the matter. Following the link below, you can see the image of "A lepton event - a neutrino ...
2
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0answers
35 views

Quantum Efficiency Estimation

Might there be a way to do a rough estimate of the quantum efficiency of a photo-detector like a CCD or CMOS sensor based only on a picture taken with it? I've read papers and guides (like this one: ...
2
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0answers
63 views

Improvements on a makeshift dessicator

I am a first year undergrad working in a lab, and I have these Plexiglass containers that I tried to convert to dessicators, since the commercial bell jars are really expensive. I used these weather ...
1
vote
1answer
192 views

Light filter for an experiment

I'm looking for a filter that lets through as many wavelengths as possible (from 200 to 5000 nm). Is that even possible?
1
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1answer
28 views

Is it possible to measure the spin of an electron without moving it?

I know that the position and spin operators commute, so it is theoretically possible. What I want to know is, what experiments currently exist that achieve this?
1
vote
2answers
114 views

What is the best thermal heatsink compound?

Re-worded This is about the Experimental Physics not PC building or how to grease a car's radiator. I have to insert a stainless steel enclosed PT100 into a block of metal to monitor its temperature ...
1
vote
1answer
251 views

Measuring depth or height from sea level

How is the depth or height relative to sea level measured? Well, if it's near the ocean, it can be easily measured manually, but what if it is 100 km away from the sea? What method is used?
1
vote
1answer
40 views

What is the easiest way to demonstrate low magnetic flux NMR on the bench?

I'm trying to build my own low fux density bench NMR set-up, and am well-versed in electronics. Continuous Wave is supposed to be the easiest. I see commercial instruments that stimulate elements in ...
1
vote
1answer
182 views

Conductive glue

I would like to use some conductive glue to contact a silicon chip's back gate. Any suggestions on what to use? Can I use thermal silver paste? I would be operating at cryogenic temperatures below 4K.
1
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0answers
30 views

How do modern particle detectors identify and segregate different particles

What is the specific particle detector technology used at CERN or similar Institutions. Is it essentially a big digital camera? When said particles are detected, how are they segregated, How does this ...
1
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0answers
30 views

How to produce sine wave heat generator?

I have taken a lab course this semester and in the experiment of finding thermal diffusivity of brass they are using square wave heat generator(by a simple circuit which gets on and off at regular ...
1
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0answers
60 views

A follow up on “Double Slit Experiment in a Bubble Chamber”

The exact title is "Has a double slit experiment ever been done using a track chamber or even contemplated?". I was totally unfamiliar with the concept of the bubble chamber, so I did some amateur ...
1
vote
1answer
49 views

Why is non-abelian property of Majorana fermion so difficult to observe experimentally?

Kouwenhoven's group observed experimental signatures consistent with the realization of Majorana bound states in semiconductor nanowire. (Mourik et al. 2012 Science 336, 1003, http://www.sciencemag....
1
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0answers
31 views

Given temp and conductivity can I back-calculate to resistance, in order to plug in a new temp value and calculate a more accurate conductivity?

Background: I used a small CTD (conductivity, temperature, depth) recorder to log a series of dive profiles in a mixed coastal estuary. The recorder logged observed temperature and conductivity every ...
1
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0answers
44 views

Any photon colliders in the past?

People have been thinking about a photon-photon collider (see this and this) as an add-on or to supplement the ILC, the next generation linear collider. My question is, have there been any photon-...
1
vote
1answer
4k views

holographic projection in thin air? [duplicate]

from where I come from ,they taught us in high school that it is possible to project holograms in thin air simply by illuminating the hologram with the "correct light" , and having a semi transparent ...
1
vote
1answer
67 views

How sodium atoms in lamp are energized to produce light?

In a recent spectroscopy lab I performed for one of my classes we used a Lambda Scientific LLE-1/2 mercury/sodium lamp (to look at the sodium doublet) and a Lambda Scientific LLE-8 hydrogen/deuterium ...
0
votes
1answer
229 views

Hydrogen Spectra using Hydrogen Gas Discharge Tube

I am doing an experiment for my lab work which include determination of value of Rydberg Constant using method of Interpolation. For this we first plot calibration curve for various wavalengths ...
0
votes
3answers
122 views

Do nanoscopes exist?

We are mostly all familiar with a microscope, and know that it helps to see MICRO components, like stuff that is photolithographically etched on silicon semiconductor die. (The latter can also be ...
0
votes
1answer
43 views

How did Cavendish measure the deviation of light from the Sun?

On today's date in 1731 was born Henry Cavendish. He is mainly know for his Chemistry research, however, while I was reading his biography I've noticed that he also calculated the bending of light due ...
0
votes
1answer
492 views

How long does it take to scan a typical scanning electron microscope image?

I suppose the answer depends on resolution and imaging area, but can you provide some ball park measures of imaging times with an SEM?
0
votes
1answer
396 views

How quickly does a small piece of molten steel cool at room temperatures?

Say I have a $(\frac{1}{2}D)^2 \pi \times \ell = (.05)^2 \pi \times .03 \approx 0.000236 \ \text{mm}^3$ piece of molten steel freshly spewed out of a hot nozzle. Now assuming the nozzle moves away ...
0
votes
1answer
100 views

Future of colliders and technical limitations

Are there any technical limitations (theoretical or technological) that prevent quark based colliders? ie. Colliding two quarks together.
0
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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....
0
votes
2answers
50 views

What does J cm-1 stand?

For an optical component, I got following number as an optical damage threshold from the company, damage threshold = 10 Jcm-1,20ns, 20Hz It looks like 20ns is ...
0
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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 ...