Constant power and temperature coil

Abstract

A coil apparatus is described that incorporates two or more conductors, wound in parallel, following the same path, in intimate physical contact throughout the path but electrically isolated. The current applied to each of the coils can be selected independently. The field generated by the coil, or force on the coil in a magnetic field, is proportional to the algebraic sum of the currents. The power applied to the coil is proportional to the sum of square of the currents. By independently selecting the appropriate current's to apply to each of the conductors, a desired field, or force, can be generated by the coil for any desired power applied to the coil. By judiciously selecting appropriate currents to apply to each of the conductors, a range of fields, or forces, may be selected for which a constant power may be applied to the coil. A constant power enables the coil to operate at a constant temperature.

1 . An apparatus comprising 
 a first conductor configured to produce a first magnetic field;    a second conductor configured to produce a second magnetic field, the sum of the first magnetic field and the second magnetic field equal to a predetermined magnetic field strength;    a first current source coupled to the first conductor and configured to provide a first current to the first conductor at a first power for producing the first magnetic field; and    a second current source coupled to the second conductor and configured to provide a second current for to the second conductor at a second power for producing the second magnetic field, the sum of the first power and the second power equal to a predetermined power value independent of the predetermined magnetic field strength for a selected range of power and field strength.    
   
   
       2 . The apparatus of  claim 1 , wherein at least a portion first conductor is configured to exchange thermal energy with the second conductor.  
   
   
       3 . The apparatus of  claim 1 , wherein the first magnetic field and the second magnetic field are applied to about the same location.  
   
   
       4 . The apparatus of  claim 1 , wherein the predetermined power value is about constant over a continuous range between two values of predetermined magnetic field strength.  
   
   
       5 . The apparatus of  claim 1 , further comprising an electron beam column.  
   
   
       6 . The apparatus of  claim 1 , further comprising an electron beam lens.  
   
   
       7 . The apparatus of  claim 1 , further comprising an electron beam deflection coil.  
   
   
       8 . The apparatus of  claim 1 , further comprising an electron beam machine.  
   
   
       9 . The apparatus of  claim 1 , further comprising an solenoid.  
   
   
       10 . An method comprising 
 applying a first current to a first conductor at a first power to produce a first magnetic field;    applying a second current to a second conductor at a second power to produce a second magnetic field;    summing the first magnetic field and the second magnetic field to equal a total predetermined magnetic field strength; and    summing the first power and the second power to equal a predetermined total power.    
   
   
       11 . The apparatus of  claim 10 , further comprising disposing at least a portion first conductor about adjacent to at least a portion of the second conductor along a predetermined length.  
   
   
       12 . The apparatus of  claim 10 , wherein the resistance of the first conductor is about equal to the resistance of the second conductor.  
   
   
       13 . The apparatus of  claim 10 , further comprising applying the first magnetic field and the second magnetic field to about the same location.  
   
   
       14 . The apparatus of  claim 10 , wherein the predetermined total power is about constant for more than two values of total predetermined magnetic field strength.  
   
   
       15 . The apparatus of  claim 10 , wherein the predetermined power value is about constant over a continuous range between two values of total predetermined magnetic field strength.  
   
   
       16 . An apparatus comprising 
 a first conductor configured to produce a first electric field;    a second conductor configured to produce a second electric field, the sum of the first electric field and the second electric field equal to a predetermined electric field strength;    a first voltage source coupled to the first conductor and configured to provide a first current to the first conductor at a first power for producing the first electric field; and    a second voltage source coupled to the second conductor and configured to provide a second current for to the second conductor at a second power for producing the second electric field, the sum of the first power and the second power equal to a predetermined power value independent of the predetermined electric field strength for a selected range of power and field strength.    
   
   
       17 . The apparatus of  claim 16 , wherein at least a portion first conductor is disposed in close proximity to at least a portion of the second conductor along a predetermined length and configured to exchange thermal energy with the second conductor.  
   
   
       18 . The apparatus of  claim 16 , wherein the first electric field and the second electric field are applied to about the same location.  
   
   
       19 . The apparatus of  claim 16 , wherein the predetermined power value is about constant over a continuous range between two values of predetermined electric field strength.  
   
   
       20 . The apparatus of  claim 16 , further comprising an servo system.