Tomb of Robert Christy?
Robert Christy was a top ranked physicist who got his PhD from Oppenheimer at Berkeley in 1941. He joined the Manhattan Project during World War 2. His biggest achievement was the invention of the Christy Pit, which was a solid plug of plutonium that formed the core of the Trinity nuke and later the Hiroshima and Nagasaki bombs.
After the war, he helped Oppenheimer get a position at Caltech during the McCarthy years, when Oppenheimer lost his US security clearance. I remember Christy as a lanky emeritus professor at Caltech in the 1980s and 1990s. He’d show up occasionally for the main Thursday physics seminars, often sitting in the front rows, which were informally occupied by the senior scientists.
Christy lived a long time, dying at 96. He is buried in Mountain View cemetery near Pasadena. Recently I went there to take photos of his grave. The cemetery folks were very helpful, giving me maps with the location.
The figure below shows the order of graves, looking north. Christy is highlighted as being between Margaret Chaney and Laura Marcus.
Below is the entire cemetery.
Below is the plots around Christy. Goddard refers to a prominent headstone that is visible by the road. The 4427 shows where Christy is buried.
Below, we are looking south. Margaret Cheney appears near us. Marcus is set further back, by the road.
Christy is between them. Below is where I have walked from in front of Cheney , so now her grave is behind me. And you can see Marcus more clearly. In the forefront is where Christy should be buried.