The main use of gallium is in semiconductors where it is commonly used in microwave circuitry and in some infrared applications. It is also used in blue and violet LEDs and laser diodes. Gallium was used in nuclear weapons to help stabilize the plutonium for machining. It can be used inside a telescope to help find neutrinos. Gallium is used as a component of a certain type of solar panels. It is also used in the production of mirrors. A mixture of gallium, indium, and tin (called Galinstan) is now used in many medical thermometers. This has replaced the traditional mercury thermometers that can be hazardous. Current research to replace mercury with gallium in dental fillings is ongoing. Galinstan can be applied to aluminum so that it can react with water and generate hydrogen. It also has many medical applications. For example, gallium salts are used to treat people with too much calcium in their blood. Isotopes of gallium are used in nuclear medicine to scan patients in certain circumstances.