The Development of a Compact Pyroelectric X-Ray Generator Ross McCart Nuclear Department HMS Sultan

Project Aims Build a Pryoelectric X-Ray Source. Test and characterise the source. (Modify design if necessary) Research into increasing energy of X-Rays Possibly couple source with X-Ray collimator. (Adapt the source to enable the production of Neutrons)

X-Ray Tube

Pyroelectric Materials Non-conducting crystals develop an electric polarisation when they are subjected to a uniform temperature change. Only in crystals with a Polar axis. The requirements are fulfilled in about 10 out of the 32 crystal classes. Effect known since 314 B.C Pyroelectric effect found in motion detection, pollution monitors and in bones. Tourmaline, Sugar cane, Lithium Tantalate and Barium Niobate

Properties of Lithium Tantalate Ferroelectric Effect – Polarising the crystal LiTaO 3 Z+ Z- + --

Crystal LiTaO 3 Z- Li + OOO Ta + Li + OOO Ta +

Properties of the Crystal For a 100°C change over 180 seconds an emission current of 2x10 -8 Amps is predicted. 6.25x10 10 electrons per second The rate of polarisation per change in temperature. Negative as polarisation occurs when crystal cools. -2.3x10 -4 Cm -2 K -1 for LiTaO 3 Pyroelectric ConstantEmission Current

Potential Difference CgCgC CgCgC

X Ray Production Source Amptek Cooling Cycle Heating Cycle

Setup

Advantages and Disadvantages Low power, approximately 1.4mW. Runs on a 12V battery or power supply. Handheld and portable. No Radioactive Sources. Solid State – no moving parts X-Ray Flux approximately 10 8 Photons per second Isotropic production of X-Rays Not a continuous flux Cannot be turned off instantaneously Limited end point energy with one crystal setup.

Potential Uses Security X-Ray fluorescence Radiography Teaching and Research Bomb Disposal Non-destructive testing Wikipedia

Neutron Generation 2.45MeV 14.10MeV The potential barrier of deuterium is 288keV, however the deuterium ions are able to tunnel under the barrier, lowering the energy required.

Goals Short Term Complete Build Characterise the electric field from X Ray emission Research Areas of Interest Two Crystal Setup – Increasing Tube Potential Stacking Crystals – Increasing Crystal Thickness Continuous Flux Using Multiple Crystals

Acknowledgments Dr Ian Giles Dr Kirk D Atkinson Miss Samantha Morris Sean Jarmen And other members of staff at the Nuclear Department. Any Questions?