Momentum offset

Measured 2025-11-22

SA.RevFreq-ACQ for RF frequency - not logged, use SA.RevFreq-ACQ-D, however this is an UCAP device and seems to have truncated values.

Supercycle SFTPRO1 - MD - MD1 - SFTPRO1 - MD - LHCION - MD1

Start flat top 1: 43375.3488 Start flat top 2: 43375.3484

We look at times 11:00:00 - 11:30:00

RF frequencies

43375…

SFT1

.3483 .3485 .3485 .34862

SFT2

.3488 .3486 .3486

Since the numerical precision of the logged RF frequencies are too low we must note them down by ourselves.

Hand-derivation

RF frequency is written as

$$f_{\text{RF}}=f_{\infty }\beta$$

Where

$$f_{\infty }=\frac{hc}{2\pi R}$$

and

$$\beta =\frac{B}{\sqrt{B^2+\frac{c^2{m}_0^2}{{\rho }^2{e}^2}}}$$

For fixed-target, $f_{\infty }$ is $43397.8660\text{Hz}$ with $h=1$.

For flat-top field of $1.80$, and hysteresis perturbations up to $3\times 10^{-4}T$, we can expect variations in $\Delta \beta \approx 4\times 10^{-10}$ , which results in $\Delta f_{\text{RF}}\approx 2\times 10^{-5}\text{Hz}$, well below the resolution limit of the logged data.