University of Wisconsin-Madison Physical Sciences Lab

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Grant for Upgrades

Thursday, October 4th, 2018

PSL, and three other universities, was awarded a $1.6 million grant from the National Science Foundation to improve the winding process for the Deep Underground Neutrino Experiment (DUNE) Anode Plane Assembly (APA). PSL has built four APAs for the ProtoDUNE detector at CERN in Switzerland, two other APAs were built by Daresbury Laboratory in the U.K.

The winder winds 24 kilometers (or 15 miles) of thin copper beryllium wire around a frame that is 6 meters (20 ft.) by 2 meters (6 feet). There are four layers of wire: the bottom and top layers are wound from one end of the frame to the other, the middle two layers are wound in a diagonal pattern. Winding is very difficult and time consuming, and with 300 APAs to be built for DUNE, it is vital to find efficiencies. This grant enables PSL, and its partner APA “factories” at the University of Chicago, Yale University, and Syracuse University, to further optimize the APA construction and winding process.

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View Through the Screen

Friday, February 3rd, 2017

In the building formerly known as the Synchrotron Radiation Center, PSL is building the newest neutrino detector for the Deep Underground Neutrino Experiment (DUNE). Rather than using the familiar photomultiplier tubes, like were used for the IceCube project, the DUNE project uses tiny wires wound around metal frames (Anode Panel Assembly or APAs) that are submerged in liquid argon at a temperature of -303 degrees F (or -185 degrees C). PSL, along with a lab in the United Kingdom, has been tasked with building the APAs.

Each APA consists of a stainless steel frame that is 20 feet long (6.3 meters), a layer of copper mesh, and 24 kilometers (almost 15 miles) of very thin copper beryllium wire wound around it. The wire is wound in four separate layers that are 1 cm apart. Due to the length of the wire, and number of wraps, it was too difficult to wind manually. PSL worked with a company to design a machine that would automatically wind the wires. Each wire is then soldered to a circuit board, with thousands of individual solder connections per APA.

We are building the first APA currently, and will be building two more, before shipping them to CERN for a small scale test.

Teaching the Future

Thursday, December 17th, 2015

Back Row: Tyler Doering, Willis Perley
Front Row: Barry Shepherd, Michelle Halpert, Tyler Trickle

This past summer, PSL started an internship program with four UW Engineering students, and a student from Madison’s LaFollette High School. This internship program exposed the students to real world engineering, and the variety of projects PSL is working on. They worked on the Anode Plane Assembly for DUNE, a project for Princeton Plasma Physics Lab, as well as an ice drilling test facility that will be here at PSL.

PSL’s Darrell Hamilton teaching the interns metrology, performing precision measurement on a DUNE APA.

Barry and Michelle assist moving the APA frame.

From Many, One

Wednesday, July 22nd, 2015

UW-Madison’s Forest Products Lab contacted PSL with an interesting problem. The computer, which runs a Spex Fluorolog 2 Fluorescence Spectrometer, needed to be upgraded since it was 20 years old. Unfortunately, the card that talks to the spectrofluorometer inside the computer wasn’t compatible with modern PCs. PSL Electrical Engineer Dan Wahl created an instrument, called RetroSPEX, which translates signals to and from the spectrofluorometer into a standard USB port.

The left image is the side that connects to the spectrofluorometer, the right image is the USB connection.

In order to design the instrument, Dan needed to reverse engineer the connections, understand what needed to be controlled and how to control the components. Armed with that information, he was able to design:

“The RetroSPEX controller combines a Microprocessor + FPGA + ADC/DAC + High voltage power supplies into a compact form. The connectors on the back panel of the RetroSPEX match the cabling of the original instrument.”

The new and old computers, with the RetroSPEX instrument on the far right.

Once the instrument was designed, a text based application programming interface (API) was created to make the computer be able to issue command, through the RetroSPEX instrument. Since the API isn’t user friendly, James Luscher Engineering Services was hired by the Forest Products Lab to write a Python-based user interface.

A screenshot of the user interface.

This is a spectrum captured by the spectrofluorometer following the installation of the RetroSPEX unit.

FLAMe on the Water

Thursday, April 30th, 2015

PSL’s Terry Benson (right) holding the new FLAMe unit with UW Limnology’s Luke Loken holding the FLAMe prototype.

Professor Emily Stanley’s lab in the UW-Madison Center for Limnology, or the study of inland waters (lakes, rivers, streams, resevoirs, etc.), created a boat mounted water testing rig called FLAMe (Fast Limnology Automated Measurement). This device can test for a number of different parameters (including water pH, CO2 levels, and nitrates) while the boat is moving at speeds up to, and exceeding 25 mph.

Limnology approached PSL to make a number of improvements. Led by PSL mechanical engineer Terry Benson, the following changes were made:


  • more rugged
  • more secure
  • made more modular, to increase options of testing devices
  • easily adapt to more boats, and positions on the boat.

The FLAMe unit mocked up at PSL.

    The piping was switched from galvanized steel to stainless steel, which means:

  • Less contamination of the water being tested.
  • More adjustability
  • More modular, to increase options of testing devices
    Overall, the unit improved:

  • Useability
  • More options due to the modularity of the unit.
  • Ruggedness
  • Made it easier to work on in the field.
  • Aesthetics were improved greatly!

Later, the rig was tested in Limnology’s testing boat, and the test went very well.

A close-up of the clamp.

This project is a result of PSL’s Pro Bono program, which helps UW researchers to design and build research instrumentation for a reduced, or no cost.

Water Counter: Counting on Upgrades

Thursday, February 26th, 2015

Inside of the box, with the new circuit board installed.

This box is one of four units supplied by the Wisconsin Energy Institute. The unit counted the presence of water by responding to a conductive path between an AC signal generator and rectifier circuit. The box was originally designed and constructed by a graduate student, however, the units never worked reliably.

Detail of the old circuit board.

PSL was asked to fix them, and a number of methods were explored. The units were upgraded to Arduino circuit boards, which offer reliability, a large online support community, and a number of upgrade paths. Some possible upgrade paths are wireless control, and Bluetooth monitoring.

A completed box ready for delivery.

PSL in the News

Friday, September 26th, 2014

Photo: Jeff Miller

The UW-Madison news service recently ran a feature on PSL. The article touched on our ongoing work on the LBNE project, announced Bob Paulos as our Interim Director, as well as our Pro Bono project which provides reduced cost or free help on projects for UW-Madison students and faculty.

Read the article

Friday, April 25th, 2014

PSL recently received funding to assist in upgrading some plasma diagnostics on the National Spherical Torus Experiment (NSTX) located at Princeton Plasma Physics Laboratory (PPPL). The NSTX is currently undergoing a $94-million upgrade, NSTX-U, that will double its current and heating capacity and the strength of the plasma confinement magnets.

PSL mechanical engineer Ken Kriesel and CAD specialist Glen Gregerson are working with Dave Smith of UW-Madison Engineering Physics and George Labik of PPPL to design a new fiber optic front-end assembly for NSTX-U. This will pack nearly double the density of fiber optic bundles into the same small space. Fifty-four bundles (each containing 9 fibers), plus some accessory equipment including thermocouples and air cooling paths, and all the mounting, total hundreds of separate pieces including spacers and fasteners, yet must fit inside a cylindrical volume less than 2.32″ in diameter, previously occupied by its predecessor containing only 28 bundles.

A complicating factor is that since one of the requirements of the NSTX-U upgrade is to reduce the magnetic permeability of the experiment’s components, the choices of materials for machined parts and fasteners are quite limited.

Assembly of the device must be performed in place on NSTX-U, due to the space restrictions present. New features are incorporated to aid what was already a difficult assembly process with 28 fiber bundles, and will be more challenging with the increase to 54 bundles.

Comings and Goings

Friday, March 21st, 2014

PSL has undergone some personnel changes in the last few months.

Brenda Marty, a long time maintenance person, retired in January. Her position was filled by Larry Phillips, who we welcome to PSL.

Greg Vlasak joined our Machine Shop from SRC. Greg’s expertise in high vacuum welding, as well as his extensive experience, have proven to be very valuable to PSL.

Shared Admin IT person Jon Young left for a new position as the director of Change Management at the Wisconsin DNR. PSL IT staff, Eric Espe and Jason Laffin, have taken over Jon’s duties in Shared Admin as well as covering the IT requests at SRC as it closes.

IceCube is 2013’s Breakthrough of the Year

Friday, January 31st, 2014

IceCube’s discovery of cosmic neutrinos was Physics World magazine’s “2013 Breakthrough of the Year.” IceCube is the world’s largest telescope; consisting of 5,600 optical modules, which detect neutrinos, that are frozen in the ice at the South Pole. Twenty cosmic neutrinos were detected, and interacted with the telescope, enabling IceCube researchers to determine the minimum energy of these neutrinos to within 15%.

Read the article.