Detection of Ultra-Violet Radiations in SonoLuminescence Institute of Physics, Academia Sinica SL Group Dr. T.K. Wong (王子敬), Dr. S.C. Lee (李世昌), G.C. Jon (仲國慶), C.C. Wan (萬常春), J.Q. Lu (路家棋), F.K. Lin (林楓凱), Yi Yang (楊 毅) Department of Physics, National Central University Dr. T.S. Yih (易台生), H.L. Fu (傅學亮) 2005/02/03

OUTLINE Why the ultra-violet radiations are so important?! How can we measure the ultra-violet radiations?! What are the results we have got?! Summary

INTRODUCTION WHAT IS SONOLUMINESCENCE (SL) ?? A gas bubble in water was TRAPPED into an EXTERIOR STANDING SOUND WAVE, and the gas bubble EMIT LIGHT !!

WHY ?! The light emission mechanism of the collapsing bubble (sonoluminescence) is still unknown. Is there any high energy photons emitted ??  The most important thing in single bubble sonoluminescence (SBSL) is temperature

That’s why we are so interesting in temperature.

Only “visible light” (400nm~800nm) can penetrate the water. So, we can get the temperature of SBSL is through fitting “the blackbody radiation curve”. That small portion of the curve, can not tell us, for sure, that it is the blackbody radiation Water absorption spectrum 25,000K Blackbody radiation curve

OUR GOAL : Doing the FIRST observation of ultra-violet radiations in single bubble sonoluminescence. And we find an experimental method to do the wavelength shifting of the high energy photons into the “visible light”, by Using Scintillator

HOW ?! How scintillator works ??  slower decay curve (ns) compare to prompt SL curve (ps) fluorescence

So, we need to find a RIGHT SCINTILLATOR. The idea is simple, but there exists a BIG PROBLEM. And we can not use ORGANIC LIQUID to generate SL. “Almost all kinds of scintillators needed to be solved in an ORGANIC LIQUID.” So, we need to find a RIGHT SCINTILLATOR.

Quinine is a strongly fluorescent compound in dilute acid solution with two excitation wavelengths (250 and 350 nm) and a fluorescence emission at 450 nm. And the acid is solved in water. Absorption and Fluorescence ~250nm 400nm Visible light

Is it really the blackbody radiation?? The spectrum of smaller than 300nm from Quinine fluorescence, and 300nm~800nm from direct observation. Is it really the blackbody radiation?? Different temperatures give different ratios of FL/direct obser. Indirect Quinine FL Direct Quinine FL Direct observation

OUR MEASUREMENT The absorption and emission spectrum of Quinine.

Pulse shape of SL for pure water and quinine water.

Assume the sonoluminescenc is the BLACKBODY RADIATION. Two different Quinine emission processes. 1. E  Quinine*  FL light (direct FL)  T ~ 10,000K 2. E  H2O*  Quinine*  FL light (indirect FL)  T ~ 100,000K

FUTURE WORK Measure the SL spectrum with (1) pure water (2) Quinine water. Work out the relative contribution of the two Quinine emission processes. It is the first step to be a tool for measuring the high energy photon in SL.

~ Thank You ~