- 01 Overview
- 02 How it Works
TRIUMF’s Science Technology Facility provides the expertise and specialized construction capacity for the design-to-installation creation of state-of-the-art particle detectors.
The Science Technology Facility’s two dozen staff have contributed to the fabrication, in part or full, to more than a dozen detectors for subatomic particle and nuclear physics experiments based at TRIUMF and Canadian and international collaborations.
The science and skill of detector design and construction to sense the subatomic and nuclear realms with ever greater precision is central to pushing the physics frontiers. Detectors are the eyes and ears of particle and nuclear physics experiments, and scientists can only see and hear as well as the detectors can capture the otherwise invisible physics taking place.
The Science Technology Facility’s detectors are at work probing for beyond-Standard model physics, testing fundamental symmetries and exploring extreme nuclear structure, including through detecting neutrinos (T2K) antimatter (ALPHA’s ALPHA-G antimatter detector) and searching for dark matter (DEAP-3600). These detectors locate, track, time and measure the energy of a diversity of particles, from pions to protons.
Science Technology Facility scientists, engineers and technicians have an ongoing R&D program to invent next-generation detectors. This includes the current development of digital silicon photomultipliers so that photon signals, rather than converted into an analog electrical pulse, and then back to a digital signal (as in current photomultiplier tubes), are captured digitally. This R&D on single photon detection at high speed has a variety of potential commercial spin-offs, for example a collaboration with University of Sherbrooke researchers on faster, more precise detectors for self-driving vehicles.
The Science Technology Facility has contributed to a variety of prominent international detectors including the CERN-based ATLAS LAr electronics, ATLAS ITK, and ALPHA-G experiments; and T2K and its potential successor Hyper-K, in Japan. In Canada the STF team works closely with a variety of Sudbury-based SNOLAB experiments, notably DEAP-3600, SuperCDMS and nEXO.
At TRIUMF, the Science Technology Facility has designed and built detectors, or electronics for the soon-to-be upgraded µSR materials probe and the experimental facilities PIENU, IRIS, TIGRESS, GRIFFIN, and UCN.
02 How it Works
The Science Technology Facility team works on a project basis working with collaborators to develop detectors from idea to implementation. This includes providing full support in detector design, engineering simulation, modeling, prototyping, construction, implementation, and data acquisition.
The Science Technology Facility specializes in the construction of two main types of detectors: scintillators; and gas wire chambers. Scintillators are plastic materials that emit light when they interact with a charged particle, and the light is used to gain information about the particle’s energy and time of flight. Gas wire detectors are chambers filled with a special gas mixture surrounded by a fine grid of high-voltage wires. A particle passing through the gas ionizes it, creating an electronic pulse picked-up by the wires that provide scientists information on the particle’s position and path.
Custom Detectors Built On-Site
The Science Technology Facility’s latest completed project is the TRIUMF-designed and built the ALPHA-G detector, shipped to CERN in summer 2018. The CERN-based ALPHA-G project is the first to measure the gravitational interaction of antimatter.
The detector is a two-meter-tall, 30-centimetre freefall chamber. Antihydrogen atoms will be created, captured, cooled and then dropped in the detector chamber to study if antimatter falls in the same way as matter in Earth’s gravitational field.
The ALPHA-G detector combines a gas wire chamber wrapped in a scintillator. When an antihydrogen atom hits the detector’s wall it will annihilate, producing pions, charged particles made from a quark and an antiquark with a brief lifetime of about 26-billionths of second (nanosecond). Scientists will be able to identify the point of annihilation by reconstructing a pion’s trajectory as recorded by the gas wire chamber. The timing of the annihilation will be measured to within a quarter of a nanosecond by recording the pion’s interaction with the scintillator. The outer scintillator layer will also remove background noise by deleting the information for any particle that triggers the scintillator before creating a track in the gas chamber, evidence that the particle originated outside the chamber. By combining the point of annihilation and timing data, ALPHA-G scientists will be able to calculate the rate at which antihydrogen falls in Earth’s gravity.
The STF involves five key sub-facilities, along with the TRIUMF Machine Shop which provides a range of computer-controlled machining:
The Scintillator Shop staff specialize in the machining and manufacture of custom, high-precision plastic scintillators for detectors. The facility includes a precision, oil-less machining centre (to avoid oil contamination that would corrode the plastics) that can shape plastics to within five millionths-of-a-meter. It also has a temperature-controlled oil bath for shaping plastic scintillators and light guides, often into exotic shapes to fit the complex geometries of experimental instruments.
The Science Technology Facility operates three temperature-controlled class-1000 clean rooms for the construction and assembly of detectors of a wide range of sizes. The air in these clean rooms is filtered and completely recirculated every four minutes. The largest clean room has full internal coverage by a 5t crane and a precision-ground granite slab with pneumatic presses for detector assembly.
Detector Development Area
This industrial-scale space is serviced by a 2-tonne overhead crane and includes high purity gas mixture tanks and delivery and return system to enable the assembly and testing of gas wire chamber detectors.
Detector Electrons Design and Development
The Science Technology Facility’s detector electronics sub-group operates a space equipped with an array of test equipment for the design and development of electronics systems for sensing and processing the tiny electronic signals produced by detectors. Staff combine a broad knowledge of electronic component technologies with advanced skills in 3D mechanical and multi-layer, printed circuit board design tools to produce sophisticated detector electrons. Often this involves creating read-out electronics with thousands of separate channels.
Photomultiplier Tube Test Facility
The Science Technology Facility group operates TRIUMF’s unique Photomultiplier Tube Test Facility. The facility is pushing the development of more sensitive and accurate photomultipliers tubes (PMT) for use in neutrino and dark matter detectors. This includes upgraded PMTs for the DEAP-3600 experiment at SNOLAB, and the proposed Hyper-K extension of the T2K experiment.