Tweet
The Proton Mag Forum
Don't discard the idea of capacitive discharge so readily. These days you
can buy 50 Farads (!) in a couple of cubic inches for a few dollars. These
capacitors hold energy well over 100 joules. I suspect they can definitely
be considered for polarizing current.
Peter Boetzkes
----Original Message Follows----
From: "Lee Fraser"
Reply-To: "The Proton Mag Forum"
To: "The Proton Mag Forum"
Subject: Re: Bifilar windings
Date: Fri, 19 May 2000 11:16:10 -0300
The Proton Mag Forum
1. The magnetic field is proportional to the current in the coil and the
number of turns. The curent in a coil is determined by Ohm's law I=E/R. In
this case I would suggest the higher the current the better. Also if you
double the voltage and halve the current, as was suggested the power remains
the same but apparently the resistance has doubled.
2. The polarizing current should be applied for some multiple of the spin
relaxation time (on the order of seconds). This more or less rules out
capacitive discharge as a source of the polarization current.
3. The detection time need not be very long. Under ideal conditions a
phaselock loop can acquire and lock in a few tens of cycles and the actual
frequency measurement done in a period on the order of a tenth of a second
or less.
The hardest things to deal with are noise and the high gain required to
bring the signal to a usable level.
Lee
__________________________________________________ ____________________
Don't discard the idea of capacitive discharge so readily. These days you
can buy 50 Farads (!) in a couple of cubic inches for a few dollars. These
capacitors hold energy well over 100 joules. I suspect they can definitely
be considered for polarizing current.
Peter Boetzkes
----Original Message Follows----
From: "Lee Fraser"
Reply-To: "The Proton Mag Forum"
To: "The Proton Mag Forum"
Subject: Re: Bifilar windings
Date: Fri, 19 May 2000 11:16:10 -0300
The Proton Mag Forum
1. The magnetic field is proportional to the current in the coil and the
number of turns. The curent in a coil is determined by Ohm's law I=E/R. In
this case I would suggest the higher the current the better. Also if you
double the voltage and halve the current, as was suggested the power remains
the same but apparently the resistance has doubled.
2. The polarizing current should be applied for some multiple of the spin
relaxation time (on the order of seconds). This more or less rules out
capacitive discharge as a source of the polarization current.
3. The detection time need not be very long. Under ideal conditions a
phaselock loop can acquire and lock in a few tens of cycles and the actual
frequency measurement done in a period on the order of a tenth of a second
or less.
The hardest things to deal with are noise and the high gain required to
bring the signal to a usable level.
Lee
__________________________________________________ ____________________