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	TUNER FREQUENCY RANGE STUDIES
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Four SAT files of the internal volume of one re-bunching cavity using the parameters from model "ReBunchingCavity3".

When we know the frequency of each model we will know the frequency range covered by an RFQ style tuner.

Filenames:
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51_ReBunchingCavity5_InnerVolume
52_ReBunchingCavity5_InnerVolume_TunerFlush
53_ReBunchingCavity5_InnerVolume_TunerIn40mm
54_ReBunchingCavity5_InnerVolume_TunerOut10mm

Tuner:
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The tuner diameter used is 37,5mm which is the same as used on the RFQ.
The tuner drive range is 50mm.

Model description:
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Model 51 has no tuner or port and is therefore the baseline model.
Model 52 has the tuner face sitting flush with the inside face of the cavity.
Model 53 has the tuner face poking into the cavity by 40mm.
Model 54 has the tuner face up inside the tuner port by 10mm.

Additional models to discover if the frequency shift is linear with tuner position:
Model 55 has the tuner face poking into the cavity by 10mm.
Model 56 has the tuner face poking into the cavity by 20mm.
Model 57 has the tuner face poking into the cavity by 30mm.


RebunchingCavity7:
Models to assess effect of reducing inner large radius from 72mm to 36mm
Why? Because we cannot make a cavity with a 72mm radius


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	INNER RADIUS STUDY
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Model 71 has had the inner radius changed from 72mm to 36mm.
Task: to run a simulation to assess the effect of the dimension change on the frequency and, more importantly, on the cavity efficiency (or Q value).
Reason: We cannot make the R=72mm version. We need to reduce the radius size to create an internal flat within which the cavity split can be made which in turn affects the space available for a vacuum port.
Compare to Model 51, the baseline cavity with no ports.

Model 51 results:
Frequency = 3.239525e8
Q value = 28284.9182

Model 71 results:
Frequency = 3.156833e8
Q value = 27963.8876

Results:
Model 71:	an increased volume has resulted in a decrease in frequency of 2.6% compared to model 51
Model 71:	a decreased Q value of 1.15% compared to model 51

Conclusion:
Make model 72 with a diameter reduction of 2.6% to try to bring frequency back up to 324MHz (i.e. 591mm down from 606mm).
The drop in Q is small therefore will make model 73 with a 20mm inner radius (and slightly smaller diameter at 584mm).

Model 72:
72_ReBunchingCavity7_R=36mm_D=591mm_InnerVolume

Model 73:
73_ReBunchingCavity7_R=20mm_D=584mm_InnerVolume

Results:
Model 72: 	For a 15mm reduction in diameter we have seen an increase in frequency (MHz) of 5.5 from 315.7 to 321.2
		The Q value has dropped 0.2% from 27963 to 27900

Model 73:	Reducing the internal radius to 20mm and reducing the diameter to 584mm has produced a frequency of 321.8MHz
		The Q value has dropped to 27496 which is 2.8% lower than for model 51.

Conclusions:
While it is desirable to have a large hole for pumping at some point the size of the hole will negatively impact on the current flow around the cavity. The feeling is that a 45mm hole that quickly flares out to a larger diameter pipe might be the better compromise between good vacuum performance and good cavity performance.

Next steps:	To produce 3 new models

Model 74:	to attempt to get the frequency for model 72 closer to 324MHz. We need a further 2.8MHz. 					Based on the previous frequency shift of 5.5 /  15 = 0.36MHz / mm, we need 2.8 / 0.36 = 7.77mm reduction giving a 583mm diameter.

Model 74:	74_ReBunchingCavity7_R=36mm_D=583mm_InnerVolume	

Model 75:	Model 74 with four diameter 45mm ports.
		75_ReBunchingCavity7_R=36mm_D=583mm_Ports=45mm

Model 76:	Model 74 with three diameter 45mm ports and one diameter 77mm port.
		76_ReBunchingCavity7_R=36mm_D=583mm_Port=77mm