What is the cause of sonoluminescence?

[Azael]

I am doing a project in messuring technology on sonoluminesence.
Basicly I am going to try and get a stable single bubble and do as many messurements I can possibly think of on it. Temp, pressure, spectral analysis, energy in vs energy out, ionizing radiation ect.
Im really excited about it because I think sonoluminesence is fascinating. and offcourse visualy very cool

The basic setup seems simple. I am going to use the best signal generator my prof can dig up for me, hook it up to 2 piezocheramic transducers that can manage up to 28khz and find a bottle with a resonanse frequence of about 22-25khz. I got all the details of the setup fairly worked out.

I have a few question though that I haven't been able to find answeres to. I hope some experimental physicist here have some experience with Sonoluminesence or someone that might point me in the right direction.


Is there any easier way to create the bubble than using a pipette? Preferably I would like to keep the bottle sealed all the time to prevent to much regassing with air.

Does anyone know of any study that shows light intensity in different fluids?
I have found one that claims 85% H2SO4 regassed with Ar creates SBSL 2900 times as radiant as in plain water regassed with Ar. But I doubt I will be able to mess round with H2SO4 for this project since secure handling of H2SO4 isn't possible in the room we have been given. Is there any other suitable fluid with low vapour pressure and with few heteroatoms that is easier to handle that you can think of??

This might be a stupid question, but what is the easiet way to regas a fluid with Xe or Ar after I have degassed it?

Given the short duration of the light pulses(a few picoseconds) what would be a suitable way to messure temp of the bubble in a time period fairly close to the light puls. It doesn't behave like a ideal black body.

 

[Maaneli]

Hi Azael,

I am also currently researching Single-Bubble Sonoluminescence. To answer your first question, you can also use a filament or small coil to boil water in the flask, and thus produce bubbles while also keeping the flask sealed.

To your second question, I have some references, and references to references, on my research website which have the answers to the question of how different fluids affect the light intensity of SBSL:

http://laser.physics.sunysb.edu/~maaneli/links/

http://laser.physics.sunysb.edu/~maaneli/

To your last question, you can measure the temperature of the bubble using a photomultiplier, and looking at the graph of the radiation spectrum which does actually fit a blackbody curve. The bubble temperature you will measure is ~10,000 K. And this is only the SURFACE temperature of the bubble. Putterman has measured core temperatures to be on the order of 1 million Kelvin!

Best of luck,
Maaneli

 

[Azael]

thanks a lot :)

 

[Azael]

Been working on this for a week now and tomorrow its suposed to be done. Yesterday we managed to trap a bubble but our signal generator can not give a higher output voltage than 25,8 V p-p and there is no suitable amplifier present. I think we are just slightely below the limit for the light pulses to start appearing because the bubble is stable over a fairly large intervall. From around 15 v p-p to 26 v p-p.

We also used a quite large bottle with a resonsane frequency around 16 kHz and with the amplitude as high as possible that damn sound goes straight through earplugs with ease! Feels like the sound makes my brain vibrate or something. Today I had to put a pair of headphones over my ears with the earplugs still in there and even then to much sound goes through! Tremendously anoying and I am even a bit afraid of damaging my hearing because at night I notice the sound is still in my ears faintly.

Im trying to think of alternate ways to increase the drive on the piezotranducers. One possibility would be to have one signal generator to each transducer but it would be a uggly solution since it would be a mess to balance current and voltage on two independent transducers, we have already had to parallel connect a lot of coils to manage that with one generator, and it might not be possible to syncronise the 2 generators perfectly. Might be worth a shot. We have a smaller bottle with 4 attached transducers ready though that we are going to try out tomorrow.

Its a marvelous thing to se that bubble in the bottle though. Especialy when it jumps around "collecting" other bubbles until there is only one left that comes to a halt. I just want it to glow :( Just one faint glow before tomorrow is over.

If anyone is interested I could translate some of my journal to this site and make it a guide to creating stable bubble sonoluminescence??

God had I just realies just how important fresh destilled water is for this I would not have wasted 4 hours today. Apperently our bottle of destilled water had picked up ions from the air or something during night because it was useless this morning even after degassing it. We reconnected everything in order to find the fault until we found out its the damn water that needs to be dumped.

 

[Q_Goest]

Hi Azael, I enjoyed your blow by blow description of the experiment. I've been interested in sonoluminescence since the early 90's when I first heard about Seth Putterman working on it and his claims of it focusing energy by a factor of 10^14! Feel free to keep us informed of your work, I'd be interested in hearing about it, though I have no expertise in the field unfortunately.

One thing I've read about it though, is that the light from the bubble is so dim it can't be seen under normal lighting. You have to turn the lights down very low or off and allow your eyes to adjust to the darkness. Is that correct?

 

[Azael]

Thanks. Il write a summary of the whole project that Il post here sometime this weekend or next week.

I am not in anyway a expert. Just a undergrad that choose to do this as a one week project in a class :)

Today was the last day and we didnt get it to glow :( We managed to capture the bubble in the small bottle aswell. But we just can't crank up the voltage high enough to get it to light up. We did get a very nice bubble that was stable for over a hour though.

Basicly we had a ****ty plan to begin with, didnt work as methodicaly as we should have and we had acess to crap equipment. I guess that was what our professor wanted us to learn. How to plan and execute a small project like this.

Unfortunaly I can't work anymore on the project. But I am totaly captivated by sonoluminescense so I am sure Il get back to it sometime in the future.

Ohh about the light, your probably right about the light from the bubble beeing very dim(unless its in like H2SO4). We where in a room we could darken completely though and not the slightest light :(