Developments on DC/DC converters for the LHC experiment upgrades

Astroparticle, Particle, Space Physics and Detectors for Physics Applications, 2014

The radiation hardness of commercial Silicon Carbide and Gallium Nitride power MOSFETs is presented in this paper, for Total Ionizing Dose effects and Single Event Effects, under γ, neutrons, protons and heavy ions. Similar tests are discussed for commercial DC-DC converters, also tested in operation under magnetic field.

Geiger-Müller (GM) tube based radiation detectors require high voltage DC biasing for their operation. The objective of this project is to design and implement a variable DC power supply of 3kV/10mA with short-circuit protection for GM detectors. The proposed design is based on rectification of AC 220V followed by a buck converter to generate a variable DC supply of 300V. A square wave of variable amplitude is generated from the variable DC supply through semiconductor switches. The square wave is fed to a 16- stage Cockcroft Walton’s multiplier to generate variable DC supply of 3kV with a resolution of 10V and ripple of less than 2mV at rated current of 10mA. The variable output voltage is controlled and regulated by employing feedback control using microcontroller and voltage sensors. This dissertation sums up the work done on this project. It includes requirements analysis, comparative study of different approaches followed by selection of Cockcroft Walton’s multiplier as the most appropriate design. For the selected design, a parametric study is presented based on simulation results followed by hardware implementation. It also includes the development of a feedback control system to control and regulate the high voltage DC output. The thesis includes the testing and evaluation of the implemented design and formulates suggestions for further research and development on detector bias supplies.

This paper describes custom made Low Voltage Power Supply (LVPS) system developed for the ATLAS -TileCal detector of the LHC (The Large Hadron Collider) particle accelerator at CERN, Geneva. The system is based on the use of only COTS (Commercial of The Shelf) components, is qualified to be radiation tolerant up to 40krad, and can operate in external DC magnetic field above 0.02 Tesla. The LVPS design described in this paper has been developed and produced for the ATLAS TileCal detector during the years 2001 -2007.

Astroparticle, Particle, Space Physics and Detectors for Physics Applications, 2014

Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications, 2012

In the high luminosity phase of the Large Hadron Collider (LHC) the selection of the most suitable architecture able to supply the instrumentation of the experiments represents a critical task today. The power conversion units will have to supply low voltages and high currents to the loads with reduced transmission losses and, moreover, their design will have to face the critical demand of efficiency, robustness and limited size together with the need to operate in hostile environment. The paper discusses the most promising solutions in the power supply distribution networks which could be implemented in the upgraded detectors at the High Luminosity LHC collider. The proposed topologies have been selected by considering their tolerance to high background magnetic field and nuclear radiations as well as their limited electromagnetic noise emission. The analysis focuses on the description of the power supplies for noble liquid calorimeters, such as the Atlas LAr calorimeters, though several outcomes of this research can be applied to other detectors of the future LHC experiments.

2007

For more efficient power transport to the electronics embedded inside large colliding beam detectors, we explore the feasibility of supplying 48 Volts DC and using local DCDC conversion to 2 V (or lower, depending upon on the lithography of the embedded electronics) using switch mode regulators located very close to the front end electronics. These devices will be exposed to high radiation and high magnetic fields, 10 – 100 Mrads and 2 4 Tesla at the SLHC, and 20 Krads and 6 Tesla at the ILC.

Physics Procedia, 2012

Future Collider Physics Detectors are envisioned with large granularity but we have a power delivery problem unless we fill a large fraction of the detector volume with copper conductors. LHC detector electronics is powered by transporting direct current over distances of 30 to 150 meters. This is how Thomas Alva Edison powered his light bulb. For example, CMS ECAL uses 50 kiloamps at 2.5 volts, supplied over a cable set with a transmission efficiency of only 30%. The transmission loss becomes waste heat in the detector that has to be removed. We have been exploring methods to transmit the DC power at higher voltage (low current), reducing to the final low voltage (high current) using DC-DC converters. These converters must operate in high magnetic fields and high radiation levels. This requires rad hard components and non-magnetic (air core) inductors.

Devices used in future experiments at LHC will be called to work in a very hostile environment. Power supply is a key aspect in this scenario, and new converters will be re-designed in order to meet the future requirements. Moreover, also Point of Load (PoL) converters, as circuits able to adapt the voltage level for each board, device and situation, need to be re-designed in order to meet the future specifications. In this paper, both experimental activity for verify the compliance with the hostile environment of a commercial PoL and the features of an ad- hoc designed PoL will be presented and discussed.

2007

We present a low voltage power supply system which has to deliver to the front end electronics of the ATLAS TRT detector [1] ca. 23 kW of electrical power over the distance of 55-106 m (which adds another 24 kW). The system has to operate in magnetic field and under radiation environment of the LHC experimental cavern. The system has ~ 3000 individual channels which are all monitored and controlled (voltage and current measurement). The hardware solutions are described as well as the system control software.

2021

Geiger Mueller tube is a longstanding device to detect gamma ray in it range and it still preferred in many radiation detection devices due to robustness in rough environment. The high voltage supply to support Geiger Mueller activation needs a transformer at in order to operate. This paper will discuss the effectiveness of the transformer to get satisfactory and stable high voltage. The transformers were winded manually in few sets with limited size of the bobbin and ferrite core. The transformers were applied into three different circuits to analyse the high voltage. The result of the effectiveness of the transformer and the high voltage of the circuit were discussed.