1. The X-Ray Tube Invented by: William D. Coolidge Written and Illustrated by: Eric S. Armstrong

2. With the discovery of x-rays, it was found that you could take a picture of the human skeleton. Unfortunately the early x-ray tubes were unreliable, and they did not last a long time. They were hard to use safely. In 1913, William D. Coolidge while working at, General Electric Research Center invented an improved x-ray tube. He fixed the three main parts of the old tube. He replaced the cathode with one of his own inventions, the hot tungsten filament. He replaced the anode with a tungsten disk. He took all the gas out of the tube and made a vacuum. This new tube became the first stable x- ray tube and quickly replaced the old gas filled tubes. Now x-rays could be used for medical and dental use.

3. William D. Coolidge William D. Coolidge on October 23, 1873 in Hudson MA. He was an only child, but a very good student. He left school and worked in a shoe factory for a wile, and then he went back to school. He graduated at the top of his class and got a scholarship to study at MIT. He graduated in 1896; he went to Leipzig, Germany to go to graduate school in physics. While there he met Dr.Roentgen, the man who discovered x-ray. After he graduated school he went to go work for GE Research. While he was there he developed ductile tungsten. This invention was used to improve the light bulb, the x-ray tube and electric switches. Over the course of his life he received 83 patents, lots of awards and was elected to the National Inventors Hall of Fame. He lived to be 102 years old.

4. March 4, 2012 Eric Armstrong 150 Quail Hollow Ln Clinton, TN 37716 Dear Mr. Coolidge Thank –you for inventing the high vacuum x-ray tube. This invention has improved everyone’s lives by helping find broken bones without surgery. I smashed my finger this year. I had to go to the hospital and have it x-rayed. It wasn’t broken and I am happy. Sincerely Eric Armstrong