Driven by the frontier research of particle physics, humans have built various types of colliders. At the Xiangshan Science Conference held from August 30 to 31, scientists called for a new type of collider in China - the world's first Taiwan Gamma Photon Collider.
The gamma photon collider can use the traditional accelerator to generate reverse Compton scattering with high-energy high-frequency lasers, which in turn causes high-brightness gamma beams to collide with each other.
'The concept of this collider was proposed more than 30 years ago, but there is currently no gamma photon collider built in the world. 'Professor Zhou Weiren from the American Fermi Lab explained that there are two reasons behind it. .
On the one hand, the development level of laser technology is not mature. This technology has not been able to meet the requirements of the gamma photon collider until recently. On the other hand, after the concept of the gamma photon collider is proposed, scientists first think of building high-energy gamma. Ma Guangzi collider, and the basis of this collider is a high-energy electron accelerator with an energy range of 80-120 GeV (1 billion e-volts). The latter is expected to take 20 years to achieve even under today's technical conditions. .
Today, the 'Gamma Photon Collider Research Group' consisting of Chinese particle physics scientists has jointly proposed a MeV (million electron volt) level low-energy gamma photon collider construction program. They believe that this kind of collision The machine can be realized on the basis of existing laser technology and particle accelerator.
Since the 1980s, the laser power density has increased rapidly, from 1016 watts per square centimeter to 1022 to 1023 watts per square centimeter. 'Huang Yongsheng, a researcher at the Institute of High Energy Physics, Chinese Academy of Sciences, introduced the low-energy gamma photon collider to laser technology. The requirements are relatively low, and the existing laser technology can meet its threshold.
Compared with the high-energy gamma photon collider, the low-energy gamma photon collider also has a unique physical meaning. For example, quantum field theory has been proposed 100 years ago, but it has not been directly verified by experiments. MeV The gamma photon collider can provide a unique platform for verifying quantum field theory. In addition, the gamma photon collider can be used for new experiments and new scientific discoveries.
Huang Yongsheng believes that the construction of low-energy gamma photon colliders can drive the development of relevant domestic technologies and talents, laying the foundation for the construction of higher-quality gamma photon colliders in the future.
Two years ago, the issue of whether to build a large particle collider in China had caused great controversy in the scientific community. Compared with the former, the gamma photon collider is much smaller. According to the gamma photon collider research The team's design plan, the world's first low-energy gamma photon collider, covers an area of only 500 square meters, construction costs are expected to be 100 million to 200 million yuan, 3 to 5 years can be completed.
'Before other types of particle colliders were built by other countries. Now China has the conditions to build the world's first gamma photon collider. It should seize the favorable opportunity as soon as possible, otherwise it will be taken a step by other countries. Yongsheng said.
However, the experts pointed out that although the technical conditions for China's construction of the world's first gamma photon collider are basically mature, the challenges can not be ignored.
One of the difficulties is that the above design requires two beams of lasers and two beams of electrons to reach two precise positions and collide at the same time, which requires a picosecond synchronization technique. Although the best synchronization technology in China is now higher than picoseconds. Magnitude, but only for single beam laser and single beam electron collision, applied to dual beam laser and double beam electron collision also requires a lot of technical verification.
