Development of a thermal cooling system for a PMT (Photo Multiplier Tube) Summer Researcher Yasmine Salas Colorado State University Advisor: Dr. Julia Lyobuviksy Bio-Engineering Department University of California, Riverside Summer Researcher Yasmine Salas Colorado State University Advisor: Dr. Julia Lyobuviksy Bio-Engineering Department University of California, Riverside

Outline  Background of the Multi Photon laser microscopy  Objective  How PMT works and why a cooling system is needed  Conclusion  Acknowledgements  Background of the Multi Photon laser microscopy  Objective  How PMT works and why a cooling system is needed  Conclusion  Acknowledgements

Objective  To develop a cooling system for a PMT (Photo Multiplier Tube)  Engineer effective cooling between 5  C-35  C for Optimum performance.  Configure prototypes models using AutoCAD  Create an efficient holding container for cooling substance whether liquid nitrogen or ethanol, dry ice mixture.  To develop a cooling system for a PMT (Photo Multiplier Tube)  Engineer effective cooling between 5  C-35  C for Optimum performance.  Configure prototypes models using AutoCAD  Create an efficient holding container for cooling substance whether liquid nitrogen or ethanol, dry ice mixture.

Why use this microscope  Two-photon excitation microscopy is a fluorescence imaging technique that allows imaging living tissue up to a depth of one millimeter.  The two-photon excitation microscope is a special variant of the multiphoton fluorescence microscope. Two-photon excitation may in some cases be a viable alternative to confocal microscopy due to its deeper tissue penetration and reduced phototoxicity.  Two-photon excitation microscopy is a fluorescence imaging technique that allows imaging living tissue up to a depth of one millimeter.  The two-photon excitation microscope is a special variant of the multiphoton fluorescence microscope. Two-photon excitation may in some cases be a viable alternative to confocal microscopy due to its deeper tissue penetration and reduced phototoxicity.

Multiphoton Microscopy (MPM) -Non-linear optical technique Z z x y Ti-Sap Laser scanning mirrors spectrograph CCD PMT 3D image capability and spectroscopy Backscattering geometry = practical utility for in vivo thick-tissue applications Reduced scattering at near- IR wavelengths No out of focus absorption Very small sample volume Non-destructive to samples Deeper tissue penetration

What is a PMT?  Photo multiplier tube  Photomultiplier tubes (PMTs) convert photons to an electrical signal. They have a high internal gain and are sensitive detectors for low-intensity applications such as fluorescence spectroscopy.  Photo multiplier tube  Photomultiplier tubes (PMTs) convert photons to an electrical signal. They have a high internal gain and are sensitive detectors for low-intensity applications such as fluorescence spectroscopy.

How a PMT works

Inside the PMT

Drawing Board Create a cooling system with aluminum to obtain desired temperature and effective insulation to direct heat away from the PMT and into the cooling system.

Prototype 1 The radiator module did not work because there was to much heat flux. Temperatures would vary depending on area of the container.

Prototype 2 This model did not work because the container would create to much pressure within the box if liquid nitrogen was used, ethanol and dry ice mixture did not cool to desired temperatures.

Final Product The final module allowed a constant temperature for all sides it was also insulated with a thick compacted form of Styrofoam and substituted liquid nitrogen for a ethanol and dry ice mixture. Also a small window of contact was cut in the Styrofoam to allow a better heat transfer with the PMT.

Conclusion  Cooling system works efficiently cooling systems similar to the PMT while holding mixture of ethanol and dry ice but yet has to be tested with liquid nitrogen on a PMT, which has not yet been received.

Acknowledgements  Advisor Dr. Julia Lyubovitsky  Dr Victor Rodgers (Department of Bioengineering)  Jun Wang  BRITE (University of California, Riverside)  Advisor Dr. Julia Lyubovitsky  Dr Victor Rodgers (Department of Bioengineering)  Jun Wang  BRITE (University of California, Riverside)