The program objective is to develop low-cost large-format additively manufactured multi-layer Printed Circuit Boards (PCBs) with a target application of micropatterned detectors suitable for particle detection supporting the primary mission of the Nuclear Physics (NP) program. In particular, this effort will focus on a process that can fabricate cascaded Gas Electron Multiplier (GEM) detectors with a low-cost automated additive manufacturing (AM) approach. The proposed innovative method will support DOE needs for cathode pad chambers, cathode strip chambers, and time projection chamber cathode boards with improvements to basic nuclear physics research and isotope development and production. Current fabrication processes require a number of time-consuming and costly steps including lithography, alignment of separate layers, bonding of layers of PCBs and holes drilled and filled using plating processes. The proposed method addresses the opportunity to develop improved micropatterned detector technology that surpasses the state of the art in a number of ways including size, functionality, cost, speed and performance. ALT LLC is proposing to develop a low-cost AM tool to achieve automated assembly of multi-layer PCBs including conductive trace deposition, dielectric deposition, laser and thermal sintering and extrusion of support materials to allow multilayer stacks to be fabricated. This AM process is expected to yield low-cost scalable manufacturing without the need for expensive lithography or toxic wet etch chemicals or plating processes. ALTs AM approach would be revolutionary by enabling large format detectors (2-3x), functionality (dielectric coatings, conductive layers, integrated high density connectors, reduction in cost (estimated 10x), fast turnaround (1-2 days), and performance with respect to alignment of layers as it is self-aligned without requiring additional registration between layers. The research plan first addresses the materials, hardware, and software required to deposit dielectric, conductive regions, and support/spacer materials. Once each material is deposited and characterized independently, a GEM structure will be printed in order to demonstrate multi-material printing and alignment of a representative holed structure. Another key demonstration, particularly for multiple GEM cascades, is that support/spacer materials can be deposited and removed after deposition leaving a robust structure. Additionally, the electrodes for cathodes and anodes will be deposited to demonstrate the feasibility of robust fabrication with high-conductivity shorting-free fabrication. A final feasibility demonstration will be of multiple GEM structures printed in a single print sequence. Commercial Applications and Other Benefits ALT expects this technology platform to have a high likelihood of obtaining a marketable product due to its low cost and high functionality. This technology will enable the next generation of GEM detectors. In addition, the unique AM approach will enable a wide range of applications for 3D printed flex PCBs that include flexible electronics, embedded electronics in 3D printed objects, medical devices and wearables such as cell phones, defibrillators, pacemakers and cochlear implants. Successful implementation of the technology will have a high likelihood of attracting further funding due to ALTs unique large-format printing capability and the significant reduction in cost due to high automation of the process. Large-format flex PCBs enabling an even wider scope of potential applications. The AM process has a very high level of automation so will allow the technology to be competitive with firms operating in low labor cost countries enable PCB manufacture to come back to the U.S. The DOE has three facilities that would benefit from the proposed effort, the Continuous Electron Beam Accelerator Facility (CEBAF), The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), and the Facility for Rare Isotope Beams (FRIB) currently under construction at Michigan State University. ALT is currently collaborating with Dr. Stolz and his team at NSCL and the future FRIB in developing the proposed work. Both the RHIC and CEBAF are currently undergoing upgrades to their luminosity and electron beams, respectively. ALTs large, low-cost precision multilayer PCB technology will be useful for particle detectors supporting all of these facilities.
