Meeting with ph dt di @ cern 26 march 2013
This presentation is the property of its rightful owner.
Sponsored Links
1 / 25

Meeting with PH-DT-DI @ CERN-26 March 2013 PowerPoint PPT Presentation


  • 49 Views
  • Uploaded on
  • Presentation posted in: General

Meeting with PH-DT-DI @ CERN-26 March 2013. P rinciple of protection Scheme of KATRIN Magnets. A. Hervé /UW. 4482- Principle of Protection of Katrin Coils. KATRIN is an experiment at KIT to measure the mass of the electron neutrino. and CPS. CPS.

Download Presentation

Meeting with PH-DT-DI @ CERN-26 March 2013

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Meeting with ph dt di @ cern 26 march 2013

Meeting with PH-DT-DI @ CERN-26 March 2013

Principle of protection Schemeof KATRIN Magnets

A. Hervé/UW

4482-Principle of Protection of Katrin Coils


Meeting with ph dt di cern 26 march 2013

KATRIN is an experiment at KITto measure the mass of the electron neutrino

and CPS

CPS

Needs line of small solenoids to guide electrons


Wgts small currents large inductances

WGTSSmall currents - Large Inductances


M1 in wgts

M1 in WGTS


Meeting with ph dt di cern 26 march 2013

CPS


Principle of a coil and a cold diode

Principle of a coil and a cold diode


Apparition of a resistive zone r

Apparition of a resistive zone r

Quenchpropagatesveryquicky and generates a voltage that open the diode.

Then the coildischargessafely on itself.

This system is intrinsically safe


Typical self decay in 5 s

Typical self decay in ≠ 5 s

It is safe if the coil by construction can supportthe generated hot spot.One can spread more the energy by triggeringthe quench-heaters of the long quenched coil.


Meeting with ph dt di cern 26 march 2013

Two-coil set up

  • Quench of one coil near nominal current is likely to trigger quench of the other coil


Quench back effect

Quench-back effect


Meeting with ph dt di cern 26 march 2013

Possible problem

  • If coupling is not sufficient, one can use the quench-heaters to induce quenches of the other coils (but one needs a Quench-Detector).

  • However, at reduced current ( < 2/3rdIc) the quench-heaters are not efficient because the coils are much more stable.

  • This is where is the real risk for the multi-coil systems.


Meeting with ph dt di cern 26 march 2013

If second coil does not quench

  • Current of the unquenched coil continues to circulate through the opened diode of the quenched coil for a long time!


Real case of unquenched coil

Real case of unquenchedcoil


First risk is to over heat the connecting wires

First risk is to over heat theconnecting wires

One can show that the temperature of a givenwireat time t, is a directlydependent of:

Called the currentload in MIITS

( In adiabatic conditions!)


Second risk is to overheat the cold diode connected to its heat sink

Second risk is to overheat thecold diode connected to its heat-sink

Diodes

( Also considered in adiabatic conditions!)


Meeting with ph dt di cern 26 march 2013

Two-coil set up - final

  • The trick is to add a dump resistor to make sure the residual current will disappear in a time safe for the cold wires and the diodes


Meeting with ph dt di cern 26 march 2013

LHC quench analysis

  • This protection scheme is the one adopted by the LHC with 154 magnets in series!


Meeting with ph dt di cern 26 march 2013

LHC quench protection

  • Simplify powering an protection scheme 1/8 of LHC


Meeting with ph dt di cern 26 march 2013

WGTS


Meeting with ph dt di cern 26 march 2013

CPS


Meeting with ph dt di cern 26 march 2013

Conclusions

  • Each coil is self protected by its cold diode that allows discharge on itself.

  • Detection of quench stops the power supply, and powers the quench-heaters of the quenched coil to better spread the thermal energy in it.

  • If another coil quenches it is treated in the same way but how many coils quench in cascade is uncertain, as it depends for example of the current level.

  • After some time (≠ 30 seconds) the breaker is opened so that all currents disappear in a time safe for the cold wires and the cold diodes


  • Login