EPR Measurement

COMING......little bit lazy

Basic Instrumentation for EPR system

• HP/E4400B ( RF Function Generator)
• SR620 ( Frequency Counter)
• DS345 ( Modulator)
• EG&G7265 ( Lock-in Amplifier)
• PI Feedback Box ( HOME MADE ----UKY)
• RF amplifier
• UDT-10 or ( Photodiodes)
• ( D2 Filters)

Measurement Procedure

1. Frequency Modulation

Refer to circuit diagram. Very naively speaking,this is a frequency sweep process roughly from 9 MHz to 23 MHz. This is because all the resonance frequencies of Rb and K ,you are going to find ,in the range of our holding field reside within this range. We can know roughly where the resonance frequency is corresponding to our holding field. This is basically from theoretical calculations and also based on your personal experience in "EPR" you gathered since years. Therefore we just need to scan a short range rather than looking a signal in that huge range of 15 GHz. Just from our experience in lab. , the following ranges are sufficient as an initial step. BUT NO GUARANTY AT ALL !!! BECAUSE THIS IS NOT SO SMOOTH AND SIMPLE AS ONE CAN WRITE .

1. 10 --- 12 MHz ( Rb)
2. 15----18 MHz ( Rb + K)
3. 19----20 MHz (K)
4. 21----23 MHz (K)

Here it is assumed that the polarization is not very low. Otherwise , you are going to see some more signals for free. Also field is assumed to be in the range 25 to 27 G.

STEPS

1. AFP sweep (The real polarization measurement)