CERN Accelerating science

Exhibition Objects
Report number	CERN-OBJ-DE-003
Category	Detector
Title	lead glass brick
Description	When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.
Description (French)	Lorsque l'on regarde une image à travers cette brique de verre, elle apparaît surélevée parce que la lumière est ralentie à cause de la densité de ce type de verre. C'est cette densité (4.06 gcm-3) qui rend ce matériau attractif pour les physiciens. L'indice de réfraction de ce verre est 1.708 pour la lumière violette (400nm), ce qui signifie que la lumière le traverse à une vitesse égale à 58% de sa vitesse normal. Au CERN, le détecteur OPAL utilise environ 12000 bloques de verre de ce type pour mesurer l'énergie des particules.
Physical characteristics
Location	Building 282
Condition	Only 1 here
Owner	PUBLIC
Availability	Available
Access	Public
Additional information	Access to the pictures
File(s)	© CERNAccessing copyrighted material Total images: 1 CERN-OBJ-DE-003-1  -  GIF;ICON, JPEG Access to the pictures CERN-OBJ-DE-003-1 GIF;ICON, JPEG Access to the pictures

Many objects of this database may be borrowed: see the loan conditions.