Simplify the following text for a Grade 9 native English-speaking person.
Original: After Pierre 's death , a group of scientists at the Radiology Congress decided to honor him by naming the unit of radioactivity a curie .
Simplified: The curie is a unit of radioactivity ( 3.7 x 1010 decays per second or 37 gigabecquerels ) originally named in honor of Curie by the Radiology Congress in 1910 , after his death . Subsequently , there has been some controversy over whether the naming was in honor of Pierre , Marie , or both .