交变梯度同步加速器（Alternating Gradient Synchrotron或简称AGS）是一个位于美国纽约州长岛的布鲁克黑文国家实验室的粒子加速器。

交变梯度同步加速器的一些重大发现而荣获3个诺贝尔物理学奖:

• 1962年利昂·莱德曼、梅尔文·施瓦茨和杰克·施泰因贝格尔发现缈微中子
• 1976年丁肇中发现J/ψ介子的J部分和粲夸克
• 1980年詹姆斯·克罗宁和瓦尔·菲奇在K介子实验中发现CP破坏

The Alternating Gradient Synchrotron (AGS) is a particle accelerator located at the Brookhaven National Laboratory in Long Island, New York, USA.

The Alternating Gradient Synchrotron was built on the innovative concept of the alternating gradient, or strong-focusing principle, developed by Brookhaven physicists. This breakthrough concept in accelerator design allowed scientists to accelerate protons to energies that would have been otherwise unachievable. The AGS became the world's premiere accelerator when it reached its design energy of 33 billion electron volts (GeV) on July 29, 1960.