Optical Calibration Development for SNO+

Lead Research Organisation: University of Sussex
Department Name: Sch of Mathematical & Physical Sciences

Abstract

Some of the most exciting physics to emerge over the last decade has been in the field of neutrino physics. One of the forefront experiments here has been the Sudbury Neutrino Observatory (SNO), based in Canada. The UK has played a leading role in this project, solving the "Solar Neutrino Problem" and clearly demonstrating, for the first time, that neutrinos exists as mixed states which allow them to apparently "oscillate" from one type to another. On the heels of this tremendously successful project, a follow-on experiment is being pursued with a remarkably diverse and interesting range of physics objectives. SNO+ will use a modified version of the instrument to measure fundamental solar neutrino processes (thereby also investigating details of neutrino-matter couplings); search for non-standard modes of nucleon decay; study neutrinos generated from within the earth; look for neutrinos from galactic supernovae; and search for a very rare process called "neutrinoless double beta decay." An observation of the latter would both permit a determination of the absolute neutrino masses and would establish that neutrinos act as their own antiparticles, which could have consequences for our understanding of the matter/antimatter asymmetry in the universe. The project is anticipated to have a rapid timescale, with first data to be taken in 2012.

The ability to unravel the nature of interactions observed by the instrument requires a detailed understanding of how light is absorbed, reflected and scattered inside the detector. One of the main contributions being made by the UK involves a network of optical fibres through which different kinds of light may be directed into the detector to help understand these effects and how instrument responds to them. The work of this grant is concerned with enhancing the capabilities of this system and laying the groundwork for future development that would have wide-ranging applications.

One aspect of this involves developing a laser system capable of different wavelengths of light through some of these fibres to study light scattering. We will also look to develop a way to accurately monitor how much light gets sent through the system, which would make it useful for other measurements inside the SNO+ detector. Many other experiments also have the need for similar systems and there are even potential applications outside of particle physics, such as those involving precise monitoring in remote or hazardous environments. As one example, a group of nuclear scientists has proposed the use of a similar but much less sophisticated system to monitor real-time uranium leakage in cooling and condensation water during reprocessing.

Another aspect to be studies involves further studies of a new circuit that we have designed to produce extremely fast light pulses from LEDs. This light will also be used to send down the fibres in SNO+ to determine the timing response of the detection elements when struck by light. However, such a device would also have other applications where a reliable, inexpensive, fast-pulsed light source is required.

Therefore, the R&D associated with this application would not only have a noticeable impact on the ability of SNO+ to explore the remarkable range of scientific questions previously mentioned, but also has a natural link to critical problems in other areas of potential interest.

Planned Impact

The overall target of this research is a facility that would make fundamental advances in our understanding of a diverse range of phenomena covering areas including how stars work, the geology of the earth and the nature of the most basic building blocks of matter. Such fundamental understandings provide the foundation that underpins the whole of technological and intellectual development that continues to advance society as a whole. Another "indirect" benefit lay in the instilling of scientific interest and training of students to think creatively and to develop and apply analytical skills to difficult problems. Such skills are highly prized as they are applicable to almost every corner of society, which has benefited greatly from the significant advances made by such trained individuals. In addition to this non-specific but very real benefit, potential direct technological spin-offs include: advances in the development of scintillators and radioactive sources, both of which are topics of interest having had important applications in medicine; novel use of fibre optics, a topic of importance in areas such as telecommunications; the development of techniques to measure extremely low levels of radioactivity, a topic of interest to both public health and safety as well as national defense; unique engineering challenges (including working in and maintaining an ultra-low radioactivity environment deep underground) that push the level of understanding of materials and the uses to which they can be put.

Liquid scintillator, let alone metal-loaded liquid scintillator, is a complex substance with intricate optical properties. The absorption and scattering lengths in the target volume for SNO+ will vary from ~20m for pure LAB in the solar phase to ~6m for 0.3% Nd loading in the double beta decay phase. Precise calibration and monitoring of these properties is therefore crucial to the event reconstruction and energy resolution and, thus, to the success of the experiment in all of its phases. This proposal specifically targets these issues though further develpment of the UK optical calibration system.

A pulse-monitored laser system along the lines proposed for development in this proposal would also have the potential for wider applicability outside of SNO+. Many other experiments have the need to make use of similar systems and, to some extent, this proposal represents the continued evolution of systems successfully employed on projects such as MINOS and Double Chooz. A number of large-scale liquid detectors proposed as future projects could also benefit from such a system, such as LENA, HanoHano, HyperK and LBNE. There are also potential applications outside of particle physics. In particular, applications involving precise monitoring in remote or hazardous environments might benefit from such a system. As one example, a group of nuclear scientists has proposed the use of a similar but much less sophisticated system to monitor real-time uranium leakage in cooling and condensation water during reprocessing (Lee, Shin and Kang, Journal of Korean Nuclear Society, Vol. 33, 2001). Similarly, the further development and characterisation of a new fast driver circuit for LEDs would provide a calibration system of significant interest both to SNO+ and to the next generation of scintillator or water Cherenkov systems as well as other applications where a reliable, fast-pulsed light source is required. Therefore, the R&D associated with this application has a natural link to critical problems in other areas of potential interest. We aim to publically disseminate the information derived from this reasearch via journal and electronic publications, international conference and workshop talks and proceedings, and open discussions with academics and representatives from industry.

Publications

10 25 50
 
Description A 110-channel fibre-optic based system that injects nanosecond, high-intensity (10^3-10^6) pulses into the SNO+ detector. This system will provide continious optical calibration over the livetime of the experiment in a challenging environment.

The drivers developed for this system are faster than used before at this intensity and variation of LED wavelengths (400-650 nm).
Exploitation Route LED pulsers have found to be good, in principle. These will be used in future, similar experiments (currently taken on by HyperK).
Sectors Aerospace, Defence and Marine

 
Description We have managed to generate interest for the commercialisation of the pulsers used and developed for this grant and attracted to subsequent awards to pursuit this.
First Year Of Impact 2013
Sector Electronics,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy
Impact Types Economic

 
Description Junior Research Associateship (HW)
Amount £2,400 (GBP)
Organisation University of Sussex 
Sector Academic/University
Country United Kingdom
Start 06/2011 
End 08/2011
 
Description Marie Curie Fellowship
Amount £122,672 (GBP)
Funding ID NeutrinosSNOPlus 
Organisation European Commission 
Department Seventh Framework Programme (FP7)
Sector Public
Country European Union (EU)
Start 12/2010 
End 12/2012
 
Description Sussex Impact Acceleration Account
Amount £30,000 (GBP)
Organisation University of Sussex 
Sector Academic/University
Country United Kingdom
Start 04/2015 
End 07/2015
 
Description Associateship with IPPP 
Organisation Durham University
Department Institute for Particle Physics Phenomenology (IPPP)
Country United Kingdom 
Sector Academic/University 
PI Contribution Internal paper for the LBNO collaboration on the potential of using future reactors in Finland, produced by UG student HG Wilsenach and myself. Co-organised 2012 conference and helped fund the 'The future of Dark Matter' at the Royal Astronimocal society, which lead to the initiation of DMUK.
Collaborator Contribution Discussion, references, network, funding.
Impact Internal LBNO note. Co-organised 2012 conference and helped fund the 'The future of Dark Matter' at the Royal Astronimocal society, which lead to the initiation of DMUK.
Start Year 2011
 
Description Research-based Outreach 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Schools
Results and Impact At the University of Sussex, we run a major outreach programme within the department of physics and astronomy, originally set up as part of the SEPnet initiative. The program involves members of the department at all levels, from taught undergraduate and postgraduate students, research students, post doctorial researchers and faculty. We have a wide range of practical activities available to take out to local schools, which are boxed up with a detailed lesson plan for department members to take to take out or use on site. The majority of our outreach activities are linked to our research.
Our annual reach is to 5,000 students per year, working with approximately 800 primary school students, 3500 secondary student, and 700 A-level students, in addition to the 2,000 members of the general public that experience our events. We currently run 130 events per year, reaching school and college students at 60 different schools. We have both schools visiting the University of Sussex campus in Brighton, and we also go out to schools.
Around half of our events involve communicating the research carried out at the University direct to schools, colleges and the public.

25% of our events involve describing our particle physics research, usually consisting of a research talk (about the Large Hadron Collider, SNO+, etc) which is reinforced by practical activities (such as building cloud chambers, or visiting our research labs).

Every week during the school terms, we run a School's Lab day, where a group of students visit the University for as full day of experiments specifically designed for the GCSE, AS and A2 level syllabus. During those days, the students visit a research lab, and get the opportunity to talk with our research students about their work. In addition, visiting A-level students also have a research lecture, and get to here the latest research being done here at Sussex.

Every year, we offer masterclasses in particle physics, with one day aimed at GCSE students, and another at A-level. These days involve research-level talks, visits to labs, as well as hands on experimental experience.


We have developed links with local schools and colleges. Teachers frequently approach us to request research related outreach activities (talks, lab tours, practical activities), ask for advice or to borrow equipment for teaching. In 2013, we ran the Institute of Physics sponsored Physic Update weekend conference for teachers.

Since we began our outreach program, undergraduate numbers has risen significantly within the department, from an intake of 40 students in 2009, up to the current (and sustained) 140 students per year.
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013,2014
URL http://www.sussex.ac.uk/physics/outreach
 
Description SNO+, PPAP 2012 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Type Of Presentation Keynote/Invited Speaker
Geographic Reach National
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact 40 peers attended, PPAP meeting 2012

Increased awereness of SNO+ within the UK sceintific community
Year(s) Of Engagement Activity 2012