India-based Neutrino Observatory

N E W S
 
Latest Updates
  • Project posts in INO. Details in "Career Notices" tab. Due date 17-11-2018.
  • NGT dismisses appeal to quash EC for INO.
  • See News scroller for copy of NGT verdict and related INO Press Release.
Technical and Human Resources Development at INO
The India-based Neutrino Observatory (INO) is a multi-institutional project aimed at building a world-class underground laboratory at the Bodi West Hills near Madurai in Tamil Nadu. The collaboration is deeply engaged in design and construction of a mega science experiment called Iron Calorimeter (ICAL) for studying many key open questions involving the elusive particles called neutrinos. The magnetised ICAL will consist of more than 50000 tons of iron plates arranged in stacks with gaps in between where around 28,800 Resistive Plate Chambers (RPCs) would be inserted as active detectors. A total of about 3.6 million high speed detector signals need to be instrumented in this detector.

A conscious and consistent effort was initiated to design local components and solutions for all the engineering aspects of the project. A large-scale detector R&D effort was undertaken to develop RPCs of 2m x 2m in size for the first time in the country. We also built multi-gap RPCs and established proof of principle of their application for PET imaging. Generations of gas systems, including a closed-loop unit were developed and built with help of a local industry. The electronics comprising of indigenously developed custom ASICs and high-end FPGAs as well as programmable trigger and high-speed data acquisition systems were developed. The detectors, instrumentation and electronics that we developed are finding extensive applications by other experiments within department, institute and beyond. A brief account of these developments is given below.

Resistive Plate Chambers (RPCs)

An RPC is a particle detector utilising a constant and uniform electric field produced by two parallel electrode plates. Having learnt the science and technology of RPC design through fabrication and characterisation of small prototype chambers, we have taken the next logical step to develop larger area glass RPCs of 1m × 1m in dimensions. The glass sheets were coated with a special paint that we developed in collaboration with a paint industry and applied using a special purpose machines and processes in collaboration with the local industry. The polycarbonate spacers, buttons and gas nozzles used for the assembly of the gas gap were also developed and produced in local industry.

The ICAL detector proposes to use 2m  2m RPCs to cover about 100,000m2 of detector coverage – the largest in the world. RPCs of this large area had required design of and development of special handling system and jigs for their assembly and handling. We have successfully designed and developed this infrastructure. Several RPC detector stacks – including the magnetised mini-ICAL prototype detector operational at Madurai are in operation for many years establishing long-time performance of these large area RPCs. Large area RPCs are being successfully mass produced in the industry now.

The RPC R&D that the INO project initiated and mastered was transformed to many research and academic institutes spread all over the country. A large number of faculties, students and engineers were trained in the INO labs and we helped them all to successfully develop RPC laboratories at their own institutions. Some of these groups have also taken up detector projects to build RPC systems for other experiments as well using based on their expertise gained through collaboration with INO project. A huge number of industries were roped in to develop components and processes required for, as well as for large scale production of high-quality RPC detectors needed for ICAL experiment.

During the process of RPC detector production, several processes are required on the raw materials, often done at different places and times. In order to track the quality of the finished product, we perform many quality control tests and checks. Data from all these measurements are logged into a specially design database utility which was developed inhouse. This utility is found to be invaluable for tracking the quality of the detectors produced by the industry and same can be adapted for similar needs.

Gas Mixing and Distribution Systems

Starting with a simple rotameter based open loop system, generations of gas mixing and distribution systems were developed in house in collaboration with local industry. Pilot unit of a closed loop gas mixing and distribution system for the INO project was designed and is being operated with 2m x 2m RPCs for many years now. A number of studies on controlling the flow and optimisation of the gas mixture through the RPC stack were also carried out. Several gas systems are in operation with the RPC detector stacks – including the magnetised mini-ICAL prototype detector for many years establishing the long-time performance of these systems. Based on the design that we developed, many units of gas systems of our design were fabricated at very affordable cost in the industry and are being extensively used in every RPC laboratory in the country.

High speed electronics and data acquisition systems

The ICAL DAQ system performs a large number of tasks. It identifies physics events in the detector by forming a trigger, tracks the muons formed from the neutrino interactions with iron by storing the detector state during an event and find directionality of neutrinos through tracking and timing. It also monitors health of the RPC detectors by recording their noise rate and chamber currents periodically. Architecture of the ICAL’s electronics and DAQ systems is based on designating the RPC as the minimum standalone unit. An ASIC based analog front-end (AFE) receives RPC signals and coverts to logic signals after amplifying the same appropriately. The digital front-end (DFE) module is located at one corner of the RPC unit. DFE module comprises of several functional blocks such as a Time-to-Digital Converter (TDC) ASIC, Strip-hit latch, Rate monitor, Pre-trigger generator, ambient parameter monitors and analog front-end (AFE) control. A soft-core processor takes care of all the data acquisition (DAQ) needs, configuration of the front-end components as well as data transfer operations between the RPC unit and the back-end servers. Considerable part of the DFE module's hardware, including the soft-processor is implemented inside a high-end Field Programmable Gate Array (FPGA). Digitised data is transmitted to the back-end using the DFE's network interface. Thus, the entire ICAL detector will function like a large Ethernet LAN, with RPC units as LAN hosts together with the back-end DAQ computers. The DAQ back-end servers receive event and monitor data from the DFE modules and archive the same, besides providing all the DAQ services and user interfaces. A DC-HVDC power supply is also indigenously developed to provide bias voltage of 10KV to the RPC detector. Several test jigs were also developed for comprehensive, but rapid testing of bulk volume production of various electronic modules.

Many of the ICAL electronics components will easily find applications in similar experiments. The AFE, DFE boards as well high voltage modules could be readily used with many detectors. Besides, we also developed many boards and modules as spinoff of our development work. A compact DAQ board based on a low-end Max10 FPGA for handling complete read of four scintillator paddles/PMTs can be used to quickly setup cosmic ray test stands, mobile muon rate monitors and so on.

We also developed a number of back-end software applications using clever implementation of communication standards and hardware. For example, we port cosmic ray muon track displays from our detector stacks onto web browsers, a feature which is used for outreach purposes besides remotely monitoring the status of our detector stacks.

We also started developing a number of online monitoring systems using free and open source computer-software applications such as Nagios. Nagios offers monitoring and alerting services for servers, network switches, applications and services. It alerts users when things go wrong and alerts them a second time when the problem has been resolved. This framework is easy to adopt for any such applications.

INO Gratuate Program

In 2008 the INO graduate training programme affiliated to the Homi Bhabha National Institute, a deemed to be University, was started. Between 3-8 students are selected and undergo one year of coursework with equal emphasis on experimental projects. About 35 students have passed out and have got good post-doctoral positions in India and abroad and some have also got faculty positions in institutes and University Depts. Furthermore, detector development at IICHEP is expected to provide well-trained human resources not only for INO but also for other experimental projects in India.

Engineering Human Resource Development

INO labs – both in Mumbai and Madurai attract a large number of students during summer and winter internships as well as long term projects as part of their curriculum. Over the period of last 10 years, we have trained a few hundred masters (in Physics) and undergraduate (in engineering) students. Most of the M.Sc students trained in our labs went on do Ph.D. in best national and international laboratories and gained attractive postdoc positions, some of them are now recruited in academic positions. Most of the engineering students actually worked on developing hardware and software systems which are being used in the detector stacks as well as in the labs, some of them actually built and prototypes of components meant for ICAL detector as well. We are very happy to report, quite often these project or internship works have resulted in journal publications and conference proceedings.

We have also trained a large number of graduate students and faculty from INO collaborating institutes and helped them setting up RPC labs at their institutions. Besides graduate students from INO’s own Ph.D. programme, there are many students who work on INO physics problems as well as detector development aspects towards their thesis. We train them and help them by building detectors and setting up experiments in the INO labs at Mumbai and Madurai.

Outreach Programs and Public Engagement

INO project has attracted a huge attention – good and not so good, due to the nature of experiments and their geographical, infrastructural requirements and thus social and governmental and environmental compatibilities. So, the project took up massive outreach initiatives. Scores of outreach activities were conducted for the local people with local government support, specially designed events for the students of all ages, visits to our laboratory in Madurai, short videos by prominent scientists from all over the world, TV programmes and new paper articles and so on. We have also built many simple experiments to demonstrate to the audience the methods and purpose science research and to convince the public that these basic science experiments do not cause any harm to them or to the environment. We also teamed with local organisations to effectively communicate in the native language. The experience that we gained in engaging with general public in the pursuit of building an ambitious science lab is worth sharing with rest of scientific community at large.