\section{Canadian facilities}

\subsection{TRIUMF} \label{sec:triumf}

\subsubsection{The national and international roles of TRIUMF}

%GH: this text is taken from 2015 Brief.  The statistics and Qweak example need to be updated.

As evident throughout this report, TRIUMF, Canada's particle accelerator centre, is an important resource for many
parts of the Canadian nuclear physics program.  A large fraction of Canadian
nuclear physicists use TRIUMF as their primary experimental facility, and as
such rely heavily upon TRIUMF's capability to develop and deliver both high-quality and high-intensity beams. Because of the favourable and unique
characteristics of the rare ion beams in particular, TRIUMF is host to over
500 scientist and student researcher visits per year and has more than 50
international agreements and partnerships.  Furthermore, a major collaboration
between Canadian and Japanese partners will result in a world-leading ultra-cold neutron source at TRIUMF.  The
continued development and delivery of high-quality beams is clearly a very high
priority item of the \href{https://fiveyearplan.triumf.ca/}{TRIUMF Five-Year Plan}, and will be of great benefit to the
nuclear structure, nuclear astrophysics and fundamental symmetries
programs outlined in this report.

Moreover, TRIUMF also plays a major role as a national infrastructure support
base to the offshore portion of the Canadian nuclear physics program.  86\% of
Canada's subatomic physics research involves TRIUMF in some manner.  A
noteworthy example is the support for the Qweak experiment at JLab.  The total
NSERC support for the project was \$3.4~M,
with \$0.7~M towards construction of key elements of the hardware,
including fabrication of the water-cooled copper conducting coils and holders
for the Qweak spectrometer, development and instrumentation of a novel diamond
microstrip detector for the Hall C Compton polarimeter, and a small quartz
scanning detector used to map the event distribution across the Qweak main
detector bars.  TRIUMF provided crucial infrastructure support to the Qweak
experiment, including oversight of the spectrometer coil fabrication, and
design and construction of all of the low-noise analog electronics that were
used to read out the Qweak main detectors and auxiliary current mode
instrumentation.

%GH: new text from Makoto
TRIUMF support for the ALPHA project at CERN has allowed Canadian physicists to
make leading hardware contributions, in particular in the areas of particle detection
systems and cryogenic engineering, e.g. the design and the construction of the ALPHA-2
cryostat and a \$3.5~M radial time projection chamber for the ALPHA-g project.

TRIUMF's continued role as a base of national infrastructure
support, in addition to its role as the host of a vibrant in-house nuclear
physics program, must be maintained with very high priority.

\subsubsection{The Isotope Separator and ACcelerator -- ISAC} \label{sec:CanFac:ISAC}
TRIUMF’s rare isotope facilities cover an industrial-scale complex combining two core elements: The existing Isotope Separator and ACcelerator (ISAC) facility and the new Advanced Rare IsotopE Laboratory (ARIEL). ISAC is further divided into two experimental halls, housed in adjacent buildings: ISAC-I, for low and medium-energy experiments; and ISAC-II for higher-energy experiments.

The TRIUMF ISAC facility uses the isotope separation on-line (ISOL) technique to produce rare-isotope beams (RIB) by impinging the 520~MeV proton beam from the main cyclotron on different target materials. The ISAC facility has celebrated its 20th anniversary in 2019 and is ready to receive the beams provided by the new ARIEL facility.

The multitude of experiments that are accommodated in the ISAC facilities are listed in Secs.~\ref{sec:nucstruc}, ~\ref{sec:nucastro}, and \ref{sec:funsym}.


\subsubsection{The Advanced Rare IsotopE Laboratory -- ARIEL} \label{sec:CanFac:ariel}
%GH: text is taken from Adam's ARIEL_project_brief2020.tex

The Advanced Rare Isotope Facility is TRIUMF’s flagship project conceived to ensure
Canada’s leadership role in rare isotope science. During the period covered by the
forthcoming Long Range Plan ARIEL will move from construction to delivering science in a
phased approach that brings new capabilities online as early as possible.

Construction of ARIEL is now underway at TRIUMF with the goal to significantly expand TRIUMF’s Rare Isotope Beam (RIB) program for Nuclear Physics and Astrophysics, Nuclear Medicine and Materials Science. At its heart ARIEL contains a 350\,kW, 35\,MeV, 10\,mA electron accelerator (eLINAC) for isotope production via photo-production and photo-fission as well as a second proton beam line from TRIUMF's 520\,MeV cyclotron for isotope production via proton-induced spallation and fission. The second stage of the project, ARIEL-II, is a joint CFI funding initiative through all 19 TRIUMF member universities (at the time of the application) and led by the University of Victoria. This will allow ARIEL to be completed in the timeframe covered by the forthcoming SAP Long Range Plan. The ARIEL facility holds the promise of world-class, transformative research in five major, interlinked research areas of strategic priority at the participating universities, both for fundamental and applied research (inside and outside the NSERC SAP envelope):

\begin{enumerate}%[label=(\alph*)]
\item Elucidating our fundamental understanding of nuclei. A central goal of nuclear physics is to develop a predictive theoretical framework for all nuclei – a standard model for nuclear physics. ARIEL experiments will provide decisive input to this quest (inside NSERC SAP)

\item Searching for new forces in nature. ARIEL will provide both the beam intensities required for high-precision measurements of the weak interaction, and the multi-user capability to allow experiments to run for hundreds of days per year (inside NSERC SAP).

\item Determining how the heavy elements were produced in the universe. A full understanding of the origin of the elements is within reach. ARIEL will enable decisive measurements of the nuclear properties of the most exotic neutron-rich nuclei that will help, in conjunction with astronomical observations and astrophysical simulations, to elucidate the so-called r-process, responsible for the production of elements from iron to uranium (inside NSERC SAP).

\item Depth-controlled $\beta$-detected Nuclear Magnetic Resonance ($\beta$-NMR), pioneered at TRIUMF, provides unique access to magnetic properties at surfaces and buried interfaces in materials, electronics and energy storage devices. ARIEL will bring this technique to full fruition by dramatically increasing the time available for such studies. Probing magnetism at interfaces and surfaces of new materials (outside NSERC SAP).

\item Advancing the molecular imaging of biological systems and the treatment of diseases, including cancer. ARIEL will develop the next generation of medical isotopes for novel imaging applications and targeted alpha therapy of tumours,
providing breakthroughs in nuclear medicine ranging from brain health to cancer treatment (outside NSERC SAP).

\end{enumerate}

The ARIEL scientific program will be implemented in phases beginning with advanced beam-cleaning and preparation capabilities for accelerated radioactive beams. These new capabilities will drive forward the programs studying nuclear structure effects in exotic isotopes.
This phase will be followed by the implementation of a new production target station to receive first beams from the eLINAC. 

Neutron-rich fission fragments produced from more than $10^{13}$ fissions per second will be possible in the final implementation. 
Photo-fission will enable the study of the very neutron-rich nuclei involved in the astrophysical r-process responsible for the production of the heavy elements from iron to uranium. 

The new proton beam-line (BL4N) will deliver up to 100 $\mu$A beam onto an additional production target. In conjunction with the eLINAC production target TRIUMF will therefore go from the current single ISAC RIB production target to the parallel production of RIBs on three target stations. 
This new and worldwide unique multi-user capability will allow for a much better exploitation of the available forefront experimental facilities at ISAC. 
Aside from the tremendous gain in available time for the material science program also other experimental programs that need large amounts of beam time will be enabled by this multi-user capability of ARIEL. 
In addition, the capabilities for harvesting isotopes for investigation as potential medical diagnostic and therapeutic isotopes will be implemented through a dedicated and symbiotic target module integrated into the beam dump of the ARIEL proton beam target station.
Table~\ref{table:ariel_phased} identifies the key scientific deliverables for each new capability of the facility.

\begin{table}[htb!]
\caption{The phased approach of the ARIEL scientific program for the coming decade.
\label{table:ariel_phased}}
\begin{center}
\begin{tabular*}{6.02in}{|p{1.25in}|p{3in}|p{1.25in}|}
%\begin{tabular}{|l{0.15\textwidth}|l{0.55\textwidth}|c{0.2\textwidth}|} 
 \hline
Capability & Will deliver isotopes… & First experiments\\
 \hline
CANREB & ...to elucidate our fundamental understanding of atomic nuclei by enabling
studies of the evolution of structure and dynamics of neutron-rich
nuclei. & $\sim$2020\\
 \hline
Two simultaneous RIBs & ...as probes of magnetism at interfaces and surfaces of new functional
materials using $\beta$-NMR. & $\sim$2025\\
\hline
Photo-fission & ...to elucidate our fundamental understanding of atomic nuclei by enabling
studies of the evolution of structure and dynamics of very neutron-rich
nuclei approaching the r-process path. & $\sim$2025\\
 \hline
Proton target station & ...for molecular imaging of diseases and treatment of cancer in the ARIEL
collection station and isotopes for developing a standard model for nuclear
physics. & $\sim$2025\\
 \hline
Three simultaneous RIBs & ...to search for new forces in nature by searching for violations of
Fundamental Symmetries. It will also mark the milestone of three
simultaneous rare isotope beams delivered to users. & $\sim$2026\\
 \hline
Full driver beam intensities & ...to determine how the heavy elements from iron to uranium were
produced in the universe. & $\sim$2029\\
 \hline
Routine 9000 RIB hours per year & ...to fully exploit the new capabilities of ARIEL for all scientific programs. & $\sim$2031\\
 \hline
\end{tabular*}
\end{center}
\end{table}

The ARIEL facility is located at TRIUMF and together with the existing ISAC production target and the currently 18 experimental facilities in ISAC-I and ISAC-II a very rich and world-leading user program in all three branches of rare isotope science (nuclear structure and reactions, nuclear astrophysics, fundamental symmetries) will be carried out. The experimental facilities are predominantly operated by collaboration with strong Canadian involvement or under Canadian leadership and thus the ARIEL facility with its dramatic increase in RIB availability and further reach to the extremes of isospin, will elevate the Canadian nuclear physics community even further.

The development and construction of the eLINAC, with Made-In-Canada SRF cavities and in-house development of the electron gun, cryo-modules, beam diagnostics and machine protect systems has been an enormous achievement in accelerator science. This has also benefited the education of several graduate students in accelerator science, who are part of the only graduate program in accelerator science (University of Victoria) in Canada.

The ARIEL-I phase of the project, constructing the eLINAC, tunnel and the ARIEL building, represented a \$62.9M investment and was completed in 2014. The completion of ARIEL-II requires funding for equipment at a level of \$33.8M for which a CFI application by all 19 TRIUMF member universities, led by the University of Victoria, was submitted in 2014 and was ultimately approved by CFI and all 5 provinces which contributed matching funds. The \$4.2M CANREB project led by St. Mary's university provided key equipment for beam preparation and charge-breeding. An additional \$10M CFI application has been approved for construction of the symbiotic target station with all associated target-transfer and hot-cell infrastructure for harvesting medical isotopes. The manpower to design and construct the ARIEL-II infrastructure is provided by TRIUMF, funded through the operating funds provided by the Canadian government via a contribution agreement by NRC. The operation of the ARIEL facility will be integrated into the TRIUMF operations.

\subsubsection{Ultra-cold neutron source for fundamental physics}

%GH: intro taken from 2015 Brief
Ultra-cold neutrons (UCN) are free neutrons of such incredibly low
energies that they may be stored in material bottles.  Hotter neutrons
would simply pass through the bottle walls.  This property of being
able to bottle UCN allows experimenters to study the properties of the
neutron with amazing precision, unattainable by any other means.
Ultra-cold neutrons are ideally suited to precision experiments testing
fundamental symmetries at low energies.  The top science priorities in
the field are measurements of the neutron electric dipole moment,
neutron decay parameters, the neutron lifetime, and gravitational
interaction studies.

Experiments using UCN around the globe are limited by the number of
neutrons available to the experiment.  To advance this field of
fundamental neutron physics, a new facility is being built at TRIUMF
to deliver more UCN than ever before.  It leverages TRIUMF's 500~MeV
cyclotron via a unique combination of a spallation neutron source and
a superfluid helium UCN converter.  
%updates continue from 2020 UCN brief
This makes the TRIUMF UCN source unique, as competing 
sources are either based on solid deuterium, and/or use reactor
sources for the neutrons.  The first planned experiment is
a new, precise measurement of the neutron electric
dipole moment (EDM),  by the TUCAN (TRIUMF
Ultra-Cold Advanced Neutron) collaboration.   The EDM measurement apparatus features dual measurement cells within a surrounding magnetically shielded room (MSR), see Fig.~\ref{fig:facil_tucan_area}.

\begin{figure}[ht]
\centering
\includegraphics[width=14cm]{Figs/facil_tucan_edm_area_labeled.jpg}
\caption{Overhead view of the UCN area in the Meson hall at TRIUMF, showing the UCN source components and experimental area for the TUCAN EDM experiment\label{fig:facil_tucan_area}.  The radiation shielding has been partially removed to show the UCN source.}
\end{figure}

An upgrade of the UCN source
and EDM experimental apparatus was funded by CFI-IF in 2017, and
included partner contributions from Japan and TRIUMF.  The main Japan
contribution is the He-II cryostat at the heart of the UCN source,
which will be tested at KEK in 2020.
The medium-term plans (2022-26) involve completing
the UCN source upgrade, and constructing and beginning to run the
neutron EDM experiment.  During this time, TUCAN expects to reach the limit
of the helium liquefier facility in the Meson Hall at TRIUMF, and plans to
request a new liquefier based on a turbine system.  In the longer term (2027-2036), TUCAN 
may consider proposing upgrades as required. 
The UCN source is planned eventually to become a
user facility, and is instrumented with a second port to serve another
experiment, such as a neutron lifetime or gravitational level experiment.

%%%%%%%%%%%%%%%%%%%%%%%
\subsubsection{Longer-term upgrades: Storage Ring} \label{sec:isacupgrade}
%TriSR description here, linking AccDiv efforts back to here
%GH: only technical and outlook parts used.  Physics program should be linked to relevant sections of Chapter 3.

A low-energy storage ring coupled to an ISOL facility like ISAC would open new avenues to nuclear physics investigations that were so far hampered by too low beam intensities. The TRIUMF Storage Ring (TRISR) project with a neutron generator will create a world-wide unique facility for the measurement of neutron capture cross sections of short-lived radionuclides (see Sec.~\ref{sec:NA:TRISR} for more details.).

The major advantages of the TriSR@ISAC in contrast to the previously proposed TSR@ISOLDE project would be that

\begin{itemize}
    \item The newly-built CANREB-EBIS is the perfect injector and already provides highly-charged ions.
    \item Plans for a second acceleration path from the EBIS via a new RFQ (to be installed in the connection between the ARIEL and ISAC building into the medium- and high energy beamline) are existing and will allow to feed the medium-to-high energy sections of ISAC without compromising the ability to get beam into the low-energy area.
    \item No new building or extension needs to be constructed since the design will be adapted to fit the TRISR into the existing ISAC-I facility.
    \item The inclusion of a neutron generator in the storage ring lattice will allow for the first time to directly measure neutron capture cross sections of short-lived nuclei.
\end{itemize}

\begin{figure}[htb!]
\includegraphics[width=0.95\linewidth]{Figs/facil_TriSR-location.png}
\caption{\label{fig:facil_TriSR}{Proposed location of the neutron generator and the TRISR in the ISAC-I hall at TRIUMF. The blue boxes indicate possible locations for the electron cooling, the neutron generator, and the gas target. }}
\end{figure}

The circumference of a storage ring with E=0.1--10~MeV/u is $\approx$50~m (with a B$\rho$ of about 1.5 Tm) and requires roughly footprint of 20~m$\times$~20~m. The injection energy and $A/q$ are given by the ISAC-I medium-energy acceleration chain (150 keV/u up to 1.8 MeV/u , $A/q$ up to 6). Further acceleration inside the ring can bring the circulating ions up to about 10 MeV/u. The installation of an external ion source would allow to run tests independent of the ISAC acceleration chain and shutdown phases.

A potential space for the TRISR would be the north/east corner of the ISAC-I experimental hall (see Fig.~\ref{fig:facil_TriSR}) which is presently occupied by two beamlines which could be easily re-arranged. The remaining area is temporarily used as working space for the target module handling. With a re-arrangement of the TUDA beamline and after completion of the ARIEL project this experimental area would be ideally suited for the TRISR@ISAC project without the need to construct a new annex hall.

The upcoming years will be used to seek funding for a machine study via a 3-year NSERC Project Grant (to be submitted in 2021) and potentially a NFRF (New Frontiers in Research Fund). The rough timeline for the project after the approval of the new NSERC Project Grant would be:
\begin{itemize}
    \item 2022: Start with beam dynamic calculations
    \item 2022/23: Definition of a Physics program (White Paper); Design of cavities, electron cooler, gas target, neutron generator, RF cavity design, magnet design, power supplies specifications, vacuum system layout, electron cooler specs, beam diagnostics design
    \item 2023/24: Physics book
    \item 2024/25: Technical design report (TDR) finished including budget; CFI Project Preselection phase at partner university; Submission of Letter of Intent
    \item 2025: Submission of CFI grant for storage ring and neutron generator (project size $\approx$ C\$30-40 million) 
    \item 2026: If CFI funding successful: Start of construction
\end{itemize}

After the start of the constructions in 2026, the first commissioning of the storage ring with beam can be expected within 3 years (in 2029/30). Taking at least 1 year for full commissioning, the facility could be fully operational for first physics (Day-0) experiments in 2031. With an external ion source, the neutron generator could be installed and tested with part of the beamlines earlier, potentially already in 2028.

For the operating costs after finalization of the construction, CFI-IOF funds would be sought. For a project size of C\$35 million this would mean a request of C\$10.5 million over 5 years from 2030-34. 

The additional staff from TRIUMF Accelerator Division required for the long-term operation of the new facility as well as other operational requirements would require a increase of the NRC contributions to TRIUMF from 2026 on (in the next TRIUMF 5-Year-Plan, 2025-30 and following), as well as give the opportunity for an additional new faculty position to strengthen the connection between TRIUMF and its partner universities. 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{SNOLAB} \label{sec:snolab}
%GH: text from 2015 Brief for now
\href{https://www.snolab.ca/}{SNOLAB} is the Canadian underground science laboratory specializing in neutrino and dark matter physics. Located 2~km (1.24 miles) below the surface in the Vale Creighton Mine near Sudbury in Ontario, SNOLAB is an expansion of the existing facilities constructed for the Sudbury Neutrino Observatory (SNO) solar neutrino experiment.

SNOLAB has been developed as one of the world's premier underground
laboratories through the considerable assistance of CFI, the Governments of
Ontario and Canada, and university partners.
Besides operating one of the deepest clean underground facilities, SNOLAB developed extensive expertise in the design, construction, and operation of ultra-low background experiments. This unique expertise makes SNOLAB the lab of choice for future experiments.
As discussed in Sec.~\ref{sec:funsym}, experiments proposed for or under
development at SNOLAB may be able to address some of the most important
questions regarding the nature of the neutrino.  
The decision by the USA to
consider siting a tonne-scale neutrino-less double-beta decay experiment at
SNOLAB is very exciting, regardless of which experiment is chosen.
Particularly if nEXO is selected in the DOE decision-making process, it will
allow Canadians to leverage considerable international resources while
participating in a world-class experiment onshore.  The consultations for
SNOLAB's institutional long range plan are just getting underway, and this is
an excellent opportunity to ensure that the subatomic physics community's long
term aspirations and SNOLAB's are in alignment.

%\subsection{Nuclear Science Laboratory (NSL) at Simon Fraser University} \label{sec:nucstruc:sfunsl}
%GH: we decided not to include this, since no brief, and is not a user facility
