HRRL 03-17-2011
Accelerator Tuning
Good Tune Used for good Scan
By Dr. Kim
| Solenoid 1 | 6.8 A |
| Solenoid 2 | 10.4 A |
| Gun Ver | -0.2 A |
| Gun Hor | +0.4 A |
| Output Hor | -1.4A |
| Output Ver | -0.5 A |
| Gun HV | +9.75 (Knob Setting) |
| Gun Grid Voltage | 5.25 (Knob Setting) |
| RF frequency | 2855.816 MHz |
| Modulator HV Power Supply | 4.42 (Knob Setting) |
| RF macro Pulse Length (FWHM) | 200 ns |
| Peak Current on FC | 37.2 mAmps |
| Scope on FC | 
|
| e- Beam Energy | 14 MeV
|
Calibration
| image | OTR image | cal_h (mm/px) | cal_v (mm/px) |
 |
 |
0.04308 | 0.04204 |
 |
 |
0.04320 | 0.04228 |
 |
 |
0.04349 | 0.04181 |
 |
 |
0.04323 | 0.04196 |
 |
 |
0.04337 | 0.04212 |
| mean (mm/px) | mean (mm/px) | ||
Results
Q1
At lower current background subtraction gets worse, because singal/noise drops.
42 mA, Positive Current, X projection
emit=0.388 +- 0.008 mm*mrad, emit_norm=10.64 +- 0.22 mm*mrad
beta=1.285 +- 0.024, alpha=0.94 +-0.03
//K1*L(1/m) er K1*L sgima^2(mm) er sigma^2
Media:2011_Mar_Emit_fit_data_x.txt
parabola fit for x-projection:
parabola fit for y-projection (y in mm unit):
y = (3.69167 +-0.02346) + (-3.89000+-0.12250)*x + (4.79738+-0.13309)*x.*x
Data created from parabola fit
Media:2011_Mar_Emit_data_from_fit_x.txt
42 mA, Negative Current, Y projection
emit=0.266 +- 0.018 mm*mrad, emit_norm=7.30 +- 0.50 mm*mrad
beta=0.918 +- 0.068, alpha=0.19 +-0.06
//K1*L(1/m) er K1*L sgima^2(mm) er sigma^2
Media:2011_Mar_Emit_fit_data_y.txt
parabola fit for y-projection (y in mm unit):
y = (2.81806 +-0.03890) + (0.52202+-0.26284)*x + (2.35025+-0.34553)*x.*x
Data created from parabola fit
Media:2011_Mar_Emit_data_from_fit_y.txt
X and Y emittances are different. The parabola in X reaches min around 0.4, while in Y reaches around 0.15. Which suggests quadrupole strengths of X and Y are way different for same coil current. Which might suggest beam is not centered, because when beam is off-centered we have this can occur.
20 mA, Positive Current, X projection
10 mA, Positive Current, X projection
5 mA, Positive Current, X projection
Q4
42 mA All Other Quads off
Haven't reach minimum.
42 mA Q1_at_-2A, Q2_at_+8A, Q3_at_-6A
x-projection:
y-projection:
Fits After the Second Mapping of the Quad
With thin lens approximation method
Why y projection has bigger error?
Quad was mapping for the second time to find effective length for the different currents. Link is at [[1]].
X
x-projection:
emit=0.417 +- 0.023 mm*mrad, emit_norm=11.43 +- 0.64 mm*mrad
beta=1.385 +- 0.065, alpha=0.97 +-0.07
parabola fit for x-projection (y in mm unit):
y = (3.67838 +-0.02232) + (-4.17265+-0.22057)*x + (5.55113+-0.42056)*x.*x
Y
y-projection:
emit=0.338 +- 0.065 mm*mrad, emit_norm=9.25 +- 1.77 mm*mrad
beta=1.170 +- 0.192, alpha=0.22 +-0.10
parabola fit for y-projection (y in mm unit):
y = (2.84273 +-0.04370) + (1.02450+-0.51931)*x + (3.79913+-1.23728)*x.*x
Without thin lens approximation method
Thin lens approximation holds when is true.
In our case