The Beam Transport System (BTS) Group is an Accelerator Support Central Group (AcSCG), which takes care of the BTS instruments of all the accelerators and associated experimental facilities at IUAC. The group is responsible for the design, manufacture, operation and maintenance of accelerator magnet power supplies and other BTS associated instruments. The primary duty of the group is to perform yearly preventive maintenance of the BTS associated instruments to achieve maximum uptime with best performance. In order to achieve the throughput, the laboratory personnel work as 24 x 7 on-call team, investigate beam stoppages attributable to the power supplies and strive to minimise the repair time. More than 150 Magnet Power Supplies (MPS) are in operation, which constitute the main sub-system of the BTS instruments. These are highly-regulated (10 ppm to 50 ppm) current sources ranging in output from 10 A to 600 A and output power ranging from a few hundred Watts to 60 kW. The regulation technologies currently in use cover several types from linear transistor regulated, Silicon Controlled rectifiers (SCR) and Pulse width Modulation (PWM) with analog regulation control.
Most significantly, almost 50 % of the total magnet power supplies are developed in-house. The in-house development has resulted in easy and fast maintenance and minimises the import of spare parts. To reduce the types of spares and to simplify maintenance and personnel training, common control electronics is designed for all current rating of power supplies. The power supplies are designed with flexible arrangement for output currents and whenever possible same type of unit is used for different current rating magnets to minimise the type of power supply units.
The group is also involved in the design & development of different types of detector bias high voltage (HV) power supplies. All power supplies for germanium detectors (5 kV, 100 µA), ACS detectors (3 kV, 10 mA) and pre-amplifiers used in INGA experimental facility are designed and developed in-house. Customized operational features such as output ramping facility is incorporated in germanium detector bias power supplies to enable simultaneous biasing of detectors of the multi-detector arrays at optimal rate; this has made the biasing exercise safe, easy and fast.
Meanwhile, the group is also involved in developing some key technologies and equipments, such as Piezo-based resonance frequency tuner control for LINAC-QWR, LLRF-based controls for the Multi Harmonic Buncher (MHB) and RF cavities (Radio-Frequency Quadrupole, Drift Tube LINAC and Spiral Buncher) of the upcoming High Current Injector (HCI) facility. The LLRF controls are servo type closed loop controls with customised functionalities to control and regulate the resonance, phase and field of the HCI-RF cavities.
Other than diversified instrumentation development, the group personnel are actively participating in the development of technology as well as development of products in the area of applied superconductivity. The BTS group has made crucial and innovative contributions in the development of the “Indigenous Magnetic Resonance Imaging (IMRI)” magnet at IUAC. The group has mainly participated in the development of Sc-joints, quench protection schemes and devices, magnet powering and protection instrumentation, etc. More importantly the BTS group has developed a complete stand-alone 500 A “superconducting magnet ramping unit” utilised to characterise many sub-assemblies and components of the IMRI-magnet.
With long and continuing exposure in preventive and breakdown maintenance of sophisticated beam transport magnet power supplies, the BTS group personnel have developed special repair skills. The group has voluntarily extended this expertise to repair similar instruments for other institutes who approached through the proper channel.