Voltage Characteristics of Diodes Used for Passive Quench Protection of Low-Current Magnets

Chouhan, S.; Green, M. A.; Zeller, A. F.

doi:10.1109/tasc.2014.2362574

Cited by 6 publications

(2 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the HTS case there must be the equivalent of six back-to-back diodes in series. The diode forward voltage goes down a factor of six between 4 K and 30 K [18].…”

Section: Power Supply and Quench Protection Systemmentioning

confidence: 99%

A Cyclotron Magnet Case Study: Would Replacing the LTS Coils With HTS Coils Make Sense?

Green

Chouhan

2016

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

The cyclotron gas-stopper magnet (CGSM) at Michigan State University (MSU) was used as model for a study for whether HTS conductor is feasible for use in cyclotrons. The outside diameter of the CGSM split warm iron magnet yoke is 4 m, with a pole radius of 1.1 m. The desired field shape is obtained by shaping the iron pole profile. Each superconducting coil is in a separate cryostat. The two coils are connected in series through the warm electrical connection. Each coil is wound and potted within an 80 mm × 80 mm cross section and mounted within a 304 stainless steel helium vessel that is designed to carry magnetic forces to the magnet cold mass supports without excessive deflection. The iron is split, so that the cyclotron chamber and RF extraction system can be mounted between the two poles. This magnet has been successfully cooled down and tested at MSU to its 180-A operating current. One can ask the following question, "If one built a cyclotron magnet the size of the MSU cyclotron gas-stopper magnet, would replacing the existing LTS coils with HTS coils using a standard second generation HTS tape make technical sense or economic sense?" The report will explore the technical and economic issues of replacing an existing LTS coil with an HTS coil of the same size and shape, using 2G YBCO tape conductor commercially available in 2015 in place of the Nb-Ti used in the magnet.

show abstract

“…In the HTS case there must be the equivalent of six back-to-back diodes in series. The diode forward voltage goes down a factor of six between 4 K and 30 K [18].…”

Section: Power Supply and Quench Protection Systemmentioning

confidence: 99%

A Cyclotron Magnet Case Study: Would Replacing the LTS Coils With HTS Coils Make Sense?

Green

Chouhan

2016

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

show abstract

“…Chouhan et al studied the forward voltage of various types of hockey puck diodes (manufacturer: Powerex) at various cryogenic temperatures at the lower amplitude of the forward current [15]. The forward voltage of a single cold diode measured at 4.2 K is ∼9 V, which is too high for its application in our configuration having two cold diodes in series in each diode assembly.…”

Section: Introductionmentioning

confidence: 97%

High-power cold diodes for the protection of a 1.5 T superconducting MRI magnet system

Soni¹,

Gupta²,

Kar³

2022

Semicond. Sci. Technol.

View full text Add to dashboard Cite

The cold diodes play a crucial role in the various operational aspects of the superconducting magnet of an MRI scanner. The forward and reverse characteristics, failure modes are studied for two types of high-power rectifier diodes to find their suitability of application at 4.2 K in a whole-body 1.5 T superconducting MRI magnet system.The diodes are characterized at various temperatures ( 300 K, 77 K and 4.2 K) in the current range up to 600 A. The turn-on voltage of the diodes at 4.2 K is found to be increased by 7-12 times that of the room temperature. The diodes show negative differential resistance beyond 1 A of forward current at 4.2 K . The forward voltage stabilizes in the ranges of 1.22 -1.24 V after attaining the turn-on voltage in the range of 5-8 V. The significance of negative differential resistance has been analyzed for the MRI magnet. The long-term stability of the forward voltage has been studied at 77 K with 550 A of the forward current. Two modes of the failure of the diodes are also studied to foresee any failure during the operation of the magnet.

show abstract

Simulation of the Quenching of the Cyclotron Gas Stopper Magnet at MSU

Chouhan

Green

Zeller

2015

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Voltage Characteristics of Diodes Used for Passive Quench Protection of Low-Current Magnets

Cited by 6 publications

References 14 publications

A Cyclotron Magnet Case Study: Would Replacing the LTS Coils With HTS Coils Make Sense?

A Cyclotron Magnet Case Study: Would Replacing the LTS Coils With HTS Coils Make Sense?

High-power cold diodes for the protection of a 1.5 T superconducting MRI magnet system

Simulation of the Quenching of the Cyclotron Gas Stopper Magnet at MSU

Contact Info

Product

Resources

About