The light source at Argonne National Laboratory has been used by researchers and scientists from all around the world since March 1995. At its core, a light source is a collection of particle accelerators that produce synchrotron light. Scientists can perform a variety of experimental approaches in a wide range of areas, including chemistry, energy, cultural heritage, and engineering. In addition to basic research, this insight has also enabled some practical progress in a number of applications and in some cases contributed to far-reaching improvements, e.g. in the field of radiation medicine or in materials development. For example, it has provided the basis for improving the turbine blades of aircraft engines.

With the announced $815 million upgrade of the APS, Argonne offers the scientific community, the next level of light source technology. The upgrade will increase the brightness of the APS's X-rays by up to 500 times, which should allow researchers to get an even clearer picture of molecular and atomic structures.

The APS upgrade project will use a multi-bend achromatic (MBA) lattice design that will reduce the electron beam emittance by a factor of roughly 75. The vacuum and RF systems play an important role in achieving this significant reduction in the beam diameter. It is essential for the vacuum system to maintain a UHV pressure range of 1x 10-11 mbar while also allowing for a maximum pressure of 2 mbar (abs). To do this, the system will need to be free of hydrocarbons and all vacuum seals will require a metal sealing system.

The storage ring will have 40 sectors with a special area at the beginning of each sector. The sectors and special areas will need to be isolated from the system at times. This is a technical challenge because RF continuity to maintain electron beam performance must not be disrupted by the use of sector valves. At the same time, however, it must be possible to disconnect sections as needed while maintaining the UHV vacuum level. VAT’s Series 47 RF All-Metal Gate Valves were selected by the APS to meet the challenge.

Aerial photograph of the U.S. Department of Energy Office of Science's Advanced Photon Source at Argonne National Laboratory as of June 2014. Credit: Argonne National Laboratory

VAT’s Series 47 valves are valves that utilize a metal seal for both the valve’s bonnet seal and gate seal. They are free of hydrocarbons and rated for XHV vacuum levels. This alone is a rare capability for vacuum valves, especially producing them at production-level volumes; however, the Series 47 goes a step further and includes an RF liner that moves into the valve cavity, as the gate opens – allowing for RF continuity while the valve is open. The RF liner designs are according to each systems unique specifications.

Additional requirements from APS include an RGA scan demonstrating the valves meet their UHV specification, special high purity double packaging including a protective nitrogen atmosphere, and certifying valve performance by actuating the valve min. 200 times and baking it to 250 °C (open and closed).

VAT’s Series 48 All-Metal Gate Valves were also selected by APS for UHV isolation where an RF liner is not required. Series 48 all metal valves provide XHV vacuum capability with a hydrocarbon-free design utilizing metal seals on the bonnet and gate. The Series 48 All-Metal Gate Valves are suitable for a variety of UHV and extreme UHV applications, and meet the same RGA, certification, and packaging criteria as the RF valves of the Series 47.

VAT Inc’s Channel Manager Joshua LeBeau states “VAT is ecstatic to be a part of this project that helps Argonne to stay at the forefront of x-ray science discovery for decades to come. When the Advanced Photon Source Upgrade is finished, it will renew the APS facility, with hopes of keeping it at the cutting edge of what is possible.”

The main construction work on the upgrade is currently scheduled to begin in mid-2022 and will take approximately one year.