Emittance/TWISS parameter extraction

Using the perl/PDL script, beam sizes for Y (quad scan 0) and X (quad scan 1) were measured. These beam sizes were put into a "sdds" file so the nominal CEBAF emittance/TWISS tool could be used to plot and fit the data.

Two fits are performed a simple Least Squares Fit and one based on MINUIT. The LSF is also used to seed the MINUIT fit.

Y plot and the GUI with results for the first quad scan.

Y beam size squared vs K1*L

CEBAF graphical emittance tool with Y data and results shown

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X plot and the GUI with results for the second quad scan.

X beam size squared vs K1*L

CEBAF graphical emittance tool with X data and results shown

	emittance	beta	alpha
	(m-rad)	(m)
X quad scan1	1.3e-6	0.35	2.0
Y quad scan0	3.7e-6	0.41	2.3

Discussion

Since this was a more or symmetric setup the agreement for X and Y beta's/alpha's is encouraging. The emittance agreement is within a factor of two which isn't such an alarming discrepancy. A factor of two agreement for a CEBAF measurement is considered a success, but we have an asymmetric complicated machine.

Emittance_Test