Do Not Disturb - Low-Noise Chokes for CT Scanners
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SMP Sintermetalle Prometheus GmbH & Co KG
Press release date: November 1, 2009
Graben-Neudorf, Germany, November 2009. SMP Sintermetalle Prometheus (SMP) has developed chokes for use in computed tomography. These inductive components are exceptionally quiet in operation as well as being low-loss and energy-efficient. This has been achieved with non-magnetostrictive materials that have been developed specially for use in medical equipment.
Computed tomography or CT is a medical imaging method that is used to generate a three-dimensional image of a part of the body from a series of two-dimensional X-ray images. The CT scanner generates a narrow X-ray beam that passes through the patient's body, where the rays are absorbed to varying degrees by the different areas of the body. A series of sensors arranged opposite the X-ray tube capture the X-rays, which are then transmitted to a computer where they are digitally processed. On the resulting CT images, doctors can clearly distinguish various tissue types, such as bones, muscle and organs. To minimize patients' exposure to the X-rays, modern CT scanners must operate at a very high speed, and be very accurate. The components used in the machine must therefore operate with these characteristics.
SMP has developed chokes for a well-known German manufacturer of CT scanners. The inductive components are installed in so-called gradient amplifiers, which supply output voltages and currents that are used to control the gradient coils. These encode the resonance signals for subsequent image reconstruction. The filter and mains chokes have the task of insuring a clean sinusoidal waveform within the gradient amplifiers and must insure a low-loss feedback of the unused energy.
A unique feature of these chokes is the non-magnetostrictive powder composites from which they are made. Developed by SMP specifically for this application, these materials allow the design of exceptionally low-noise chokes to minimize the humming noise that CT scanners generate during operation - noise which can be unsettling for the patient and make it difficult for medical personnel and patient to communicate over the intercom. During the scan the patient lays on a stretcher inside the scanner and the medical personnel leaves the room so as not to be frequently exposed to X-rays. To also minimize the burden the X-rays place on the patient's body, and the length of time for which the patient has to lie still in an enclosed and unfamiliar space, CT scanners must work quickly and efficiently. SMP's energy-efficient low-loss chokes provide the performance needed to meet these requirements, and their compact design saves space in the control cabinet, which is located immediately next to the scanner itself.
In addition to medical applications, SMP's chokes are used in photovoltaics, wind turbines and in railway engineering. For these and other applications in power electronics, power generation, and instrumentation and control, SMP supplies inductive components for frequencies up to 200 kHz and current ratings up to 1000 amperes. Depending on their application, they are constructed either as single-conductor chokes for high-current applications, single-phase individual chokes, three-phase choke modules, or LC filters. These components offer a high energy storage capacity in a compact and cost-conscious design as well as reduced losses and good EMC characteristics. SMP manufactures all components to customer specifications using in-house developed powder composites. All products are RoHS- and REACH-compliant and the materials used are UL-listed. To allow for a wide range of requirements, components can be made to all common international standards.
SMP Sintermetalle Prometheus GmbH & Co KG develops and manufactures inductive components and magnetically soft materials, cores and mouldings. Based in Graben-Neudorf near Karlsruhe, Germany, the company was founded in 1982 by Vasilios Gemenetzis and today employs 180 people. Ever since the company's foundation, research and development has been a key aspect of the company's philosophy. SMP's product range includes low-loss inductive custom components based on in-house-developed powder composites, such as filter, commutating, step-up converter, power recovery and single-conductor chokes. Many of its products are used in the railway industry, in photovoltaic systems and wind turbines. SMP has become one of the key global suppliers of magnetically soft materials for industrial applications, serving customers throughout the world.