Start-Up of a Research Program in Sonoluminescence

1. Start-Up of a Research Program in Sonoluminescence • Overview of Group • Research Directions & Facilities • Observation of Fluorescence Emissions in Sonoluminescence on Water doped with Dye • Status and Plans Henry T. Wong /王子敬 Academia Sinica / 中央研究院@

2. Collaborating Groups: • AS(台灣中央研究院), CIAE(北京原子能院), NCU(台灣中央大學), NCCU(台灣中正大學), NJU(南京大學), Slovakian Academy of Science • Inter-disciplinary : expertise in particle physics, nuclear physics, optics ..... (BUT -- NO previous experience in acoustics, ultrsoncis ….. Etc.) • A smaller-scale activities in parallel with our core program

3. Research Directions: • Study processes that shed light to the underlying physics mechanism of SBSL • Explore possibilities of emissions of high energy radiations in SBSL Approaches: • Adopt and adapt techniques used in nuclear and particle physics experimentations (high energy radiation detectors, electronics, data acquisition, data analysis ….)

4. Resonators:

5. Liquid & Gas Systems

6. Data Acquisition System VME Crate PMTs VME-PCI Bus … Gate PZT-driver Synchronous Output Delay ADC TDC FADC 2.5 GHz Oscilloscope PMT PC Linux & Windows USB-GPIB

7. Observation of Fluorescence Emissions in Sonoluminescence • Motivations: • SL emissions <200 nm not been observed due to self-absorption in water • UV+HE spectra may provide information on the temperature for black-body emissions • May help to differentiate black-body from other non-equilibrium emissions models • Photon yields ratio between UV+HE & Optical is a convenient gauge of the relative temperature achieved in varying SBSL conditions.

8. Goal:devise an event-by-event analytical method to probe the UV+HE parts of the spectra Strategy:dope water with fluorescent materials, wavelength-shifted HE SL emissions to optical and differentiate it from prompt SL via pulse shape analysis

9. Absorption and Fluorescence ~250nm 400nm Visible light Choice of Dopant:Most scintillators are soluable only in organaic solvents  Need one that dissolves in water Quinine is a strongly fluorescent compound in diluteacid solution

10. Set-Up: • Quinine in 0.9% dilute sulphuric acid in water • Plastic scintillator panel for capturing cosmic rays which gives pure fluorescent emissions • Digitize pulse with 2.5 GHz oscilloscope interfaced to PC event-by-event • Temperature ranges : 2oC – 25oC

11. Average of 1000 events: Pure SL from SBSL in water(0.9% sulphuric acid) Pure FL from cosmic rays Mixed SL+FL from SBSL in Quinine-doped water

12. Items to study on SL+FL emissions : • Evolve from qualitative to quantitative • Measure UV/HE photon energy • Derivation of temperatures assuming black body emissions, after calibration (light yield  energy output) procedures • Improved DAQ system from Oscilloscope-GPIB to FADC at VME-Linux • Distributions of (a,b) with large event samples • Variations of (a,b) with ambient conditions and SBSL light yield

13. Other Research Program: • Fast DAQ Sampling (achieved 18 kHz) to study timing structures of SBSL events • Repeat/Set Up “neutron detection experiment” to look for possible neutron emissions in SL (i.e. study of SL at high acoustic pressure) • Devise techniques to measure SBSL pulse shapes, towards event-by-event modes , possibly towards HBT analysis

14. Preparation towards repeating neutron experiment at CIAE Neutron Facilities: • CIAE Pulsed Neutron Source • 14 MeV or 3 MeV • 1.5 ns spill length, repetitive rate 1.5 MHz • 1010 neutrons per spill Beamline

15. Neutron Detector : • NE213 liquid scintillator • Sensitive Area: Φ180mm×50 mm • PSD capabilities for (n,g) separation DAQ : tag neutrons with bothPSD ToF