Detector Development Laboratory

Our group has had considerable productivity and success in subatomic (nuclear/particle) physics projects, over three decades.  We collectively possess significant expertise in the use and development of nuclear physics instrumentation as well as in analysis methodology and techniques, related to a broad spectrum of sensitive detectors (photomultipliers, SiPMs/multi pixel photon counters, scintillators, Čerenkovs, time-of-flight detectors, calorimeters, etc).  We have extensive experience in working with fast detectors and in optimizing time-of-flight systems and maximizing the timing resolution following time-walk corrections.  We have designed, constructed and delivered a large complement of detectors to several subatomic physics labs (including JLab, TRIUMF, NIKHEF, INS-ES) over this period in connection to a number of subatomic physics experiments employing hadronic and electromagnetic probes.  Our impact on these fields is substantiated by our acquisition of leadership positions past and present (Experimental Spokesmen, Collaboration Chairs, Working Group Coordinators). Our team’s productivity is high in terms of instrument publications, technical reports and presentations in collaboration meetings and conferences: over 40 reports, presentations and technical documents presented since 2008.

We have systematically built an advanced detector development and testing facility mostly from NSERC funds but with periodic injections from JLab/DOE and UofR resources. Using our well-equipped detector facility we will extract current-voltage (IV) curves, gain uniformity, PDE of the SiPM individual units and arrays and study their noise and possible temperature control requirements. Arrays and their electronics will be tested to establish their operational stability in hostile environments.

The in-kind contributions in instrumentation from JLab and our team are indispensible tools in carrying out this project on SiPM array development, in addition to the equipment requested herein.  The devices can be loosely grouped into the following categories.

SiPM arrays. Their immunity to MRI-class magnetic fields and transients, compactness, large PDE and many other attributes elevate them to the next generation class of detectors, promising to replace the decades-old, work-horse device, the PMT, used currently in many academic and industrial applications.

SiPM Bias. This is lacking in our laboratory.  Previously we used the picoammeter to supply the voltage to a single SiPM channel and inexpensive (and unreliable) supplies for the amplifier voltage.

Light sources.  These include a 375 nm UV LED system and a 373nm UV laser with laser head and internal triggering electronics control.  These units can be used either to illuminate SiPMs directly or by stimulating scintillating material.

Radioactive sources. Particularly useful is our beta (⁹⁰Sr) emitter.  This is used to stimulate scintillating material.  We have studied and simulated this source and have accurately determined the resulting number of photons and photoelectrons, needed towards the PDE determination.

Scintillators, Fibres, Calorimeters.  These devices are used to convert radiation or cosmic rays to light, which can be read out directly via SiPM arrays or through clear, Lucite light gathering and focusing devices (light guides). Scintillators, either in block or fibre form, can be arranged to illuminate the SiPM surface uniformly or preferentially and/or to transport images.

L(Y)SO, LSO, LaBr₃(Ce). LSO (and LYSO) crystals are fast (40ns decay) and are used in the Siemens PET/MRI⁵.  LaBr₃(Ce) is even faster (16ns) and has potential for medical applications. We will also consider CdZnTe detectors, used in surveillance of nuclear installations for over a decade and now also being pursued for gamma-ray applications in medicine.

Protective Processes.  Light-sensitive detectors require protection from ambient, stray light. Our laboratory includes several ‘dark boxes’ and other passive systems, such as overhead light UV-blocking filters (to avoid scintillating fibre UV-based degradation).

Electronics.  These include a broad spectrum of devices, from the SiPM electronic boards, through NIM electronics (to process signals, discriminate pulses, form event logic) to CAMAC electronics (to digitize amplitude and timing information).

Measuring Instruments.  These include picoammeters (to power SiPMs and measure minute electrical currents from them and photo diodes used in the setups), a sophisticated digital phosphor 1GHz oscilloscope and digital voltmeters.

Mechanical.  This category encompasses the computer-controlled, precision X-Y scanning platter, used to translate the SiPM array across the light source footprint, towards gain uniformity scans, and custom jigs to hold SiPMs, PMTs and photo diodes in stable illumination conditions.

Data acquisition.  A linux PC with CAMAC controller interface card and loaded with subatomic physics software suite (MIDAS) is used to acquire digital signals from the CAMAC crate controller.

Computers and Analysis.  Our group possesses a cluster consisting of 10 dual-core CPUs, coupled to a 3TB storage server that can be used to analyze the acquired data, in addition to multiple desktop servers.