Bunch Lengthening System Cryostat for Advanced Photon Source Upgrade

Posted on: January 15, 2019

The Contract Award

In September of 2017, the Applied Vacuum Division of Anderson Dahlen was awarded a design-to-specification contract for the Bunch Lengthening System (BLS) Cryostat vacuum vessel, lid, gate valve enclosures, 80K thermal radiation shield, magnetic shielding, and 4K liquid helium reservoir. The completed assembly would have dimensions of approximately 7W X 5H X 4 D and be suitable for high vacuum service (1*10-7 torr). The 4K liquid helium reservoir was required to be manufactured and U-stamped in accordance with the ASME Section IX of the Boiler and Pressure Vessel Code.

The Science

Fig. 2 Aerial View of the Advanced Photon Source

The purpose of the Advanced Photon Source Upgrade (APS-U) is to produce a brighter, higher energy beam for the users to conduct critical research. The increased brightness allows for delivery of x-rays with very little spread (think of a laser pointer) which allows researchers to collect more data, with higher resolution, and in less time. As the focus of the x-rays increases, there is greater energy available for APS users to penetrate deeper inside materials (both organic and inorganic) thus revealing crucial information about a materials structure and function. From imaging viruses in search of cures to studying the structure of materials for next generation, nanoscale technology, the APS-U is the next phase of development for an already world-class research facility.

Fig. 3 Model of the HHC Installed Between the Gate Valve Enclosures

One of many key components to the APS-U is the Bunch Lengthening System Cryostat vessel and the components housed within it. The BLS is a new cryomodule containing a single-cell higher-harmonic superconducting cavity (HHC) based on the TESLA shape. The cavity (Fig. 3) operates at the 4th harmonic (1408 MHz) of the main RF and was built at Argonne as part of the APS Upgrade (APS-U) [1]. The HHC, in conjunction with an upgraded APS x-ray source, will provide a benefit to APS users by increasing both the beam lifetime and availability in the storage ring. Based on overall design changes for the APS-U, the beam life after the upgrade will be significantly shorter than the current 6-8 hours [1]. As a result, the current injection rate of once per minute into the storage ring may have to be increased. However, a single superconducting cavity could provide the necessary voltage need to lengthen the beam bunch and increase the lifetime by a factor of 2X-4X [1].

The Challenge

Aside from the vessels generally large size (7W X 5H X 4 D), Anderson Dahlen Applied Vacuum Divisions Engineers were tasked with taking the preliminary design specification and fleshing out the complete manufacturing drawings and process. Furthermore, there were a number of critical tolerances that had to be held in regards to flatness, flange orientation, and surface-to-surface relationships. A particular challenge was the gate valve enclosures that hold the HHC on either end (Fig. 3). The HHC requires alignment (+/- 0.5 mm transverse) with respect to the BLS vessel. The opposing enclosures are not only 6+ feet apart, but they are also oriented in a diagonal (V) shape in relation to one another. As a result, the inward facing (internal) conflat flanges on the gate valve enclosures were required to be aligned axially relative to each other when assembled to the vacuum vessel. In order to achieve this result, the lateral offset of the flange axes could not exceed +/- 0.010 inches and the angle of misalignment could not exceed +/- .05 degrees. Due to Anderson Dahlen Applied Vacuum Divisions extensive machining and fabricating capabilities, our team collaborated with ANL Physicists to engineer a manufacturing process that not only held the required tolerances but could form the contoured profile of the chamber from a single piece of plate. Thus, reducing cost by eliminating many linear feet of welding and increasing the vacuum integrity of the vessel.

The Result

Fig. 4 Completed BLS Cryostat Vessel Assembly

After months of collaborative design and manufacturing, Anderson Dahlen Applied Vacuum Division delivered the completed BLS Cryostat Vessel Assembly (Figs. 4 & 5) to the Physics Division at Argonne National Laboratory in the 3rd quarter of 2018. The completed contract marked our 3rd major design-to-specification build with ANL and one of the hundreds for other National Labs, R&D Centers, and OEMs. As the APS-U gets underway, the BLS Cryostat will undergo rigorous testing prior to its planned installation in 2022. Anderson Dahlen Applied Vacuum Division is proud to contribute to what is and will continue to be one of the brightest light sources on the planet!

Fig. 5 View of the Installed 80K Copper Heat Shield in the BLS Vessel

The Company

Anderson Dahlen, Inc. Corporate Headquarters in Ramsey, MN

Anderson Dahlen, Inc. (ADI) is one of the most vertically-integrated, privately-held contract manufacturing companies of vacuum/pressure vessels and non-commercially available equipment in the United States. Between our three facilities in the Twin Cities area of Minnesota, ADI has 300,000 ft2 of manufacturing space with laser cutting, water-jetting, plate/sheet metal forming, vertical/horizontal CNC machining, and welding capabilities. Our current staff of 285+ employees is comprised of 15 Engineers, 20 CAD Designers, 12 Project Managers, 85+ welders, and machinists. From critical components you can hold in the palm of your hand to large vessels (14 in diameter, 20 in length), ADI can tackle nearly any manufacturing challenge in our ISO 9001:2015 Certified facilities. Visit the link to our Corporate Video below to learn how ADI can shape your bright ideas into brilliant results!

We would invite any potential customer to visit our facilities, meet our people, and to collaborate with us. Tom Knoll, President & CEO, Anderson Dahlen, Inc.


[1] Advanced Photon Source Upgrade Project, Preliminary Design Report, Document Number : APSU-2.01-RPT-002, ICMS Content ID : APSU_1705610, Sep. 2017.