Beam Test Apr 26 2012

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Coil current vs Electron Beam Energy

Coil           En                Mod HVPS Grid Set
Current 
(Amp)          (MeV)
6.50 	 	3.49960871
15.25 	 	8.04790047        
15.3                             4.12  (En Switch off)
24 	 	12.5378648        4.30  (En Switch off)
33 	 	15.6004336        4.84  (En Switch off)

Preparation

[Check List]

1. Magnets (on/off)

2. Camera: (on/off) (Sync) (shielding)

3. Flags: (In/Out)

4. Farady Cup: hocked up?

5. Blank off for camera on?

6. Gas bottle for valve full?

7. Gas bottle for flags full?

15.6 MeV Setting

Quad Scan is done here with Q1.


Energy switch changed to low energy setting. Part of the cavity is grounded.

Energy Switch Out (High En Range)
Dipole Coil Current 33
e- Beam Energy () 15.6004336 MeV (mapping )
Solenoid 1 A
Solenoid 2 A
Gun Hor 0 A
Gun Ver 0 A
Output Hor 0.4 A
Output Ver 0.3 A
Rep Rate 6
Gun HV 8.99(Knob Setting)
Gun Grid Voltage 10 (Knob Setting)
RF frequency 2856.291 MHz
Modulator HV Power Supply 4.84 (Knob Setting)
RF macro Pulse Length (FWHM) 300 ns
Q1 (A) 0
Q2 (A) 0
Q3 (A) 0
Q4 (A) 0
Q5 (A) 0
Q6 (A) 0
Peak Current on FC 1 (45 deg) 88.8 mAmps
Peak Current on FC 2 (45 deg) 26.4 mAmps
Scope on FC 1 200 px
Scope on FC 2 200 px
Beam Spot 200 px


Gun has been up to air for 3 times. It could be oxidation, contamination. Or it could be gun died, less likely. Roasting the gun to burn off the contamination is an idea. Chad just roasted gun for with higher current, we saw gun current increased many times. We will leave roasted for one night.

En spread and En measurement

File name in Flash drive.

File Name in Flash Drive Dipole Coil Current (Amps)
tek00008.png 24
tek00009.png 25
tek00010.png 26
tek00011.png 27
tek00012.png 27.5
tek00013.png 28
tek00014.png 28.5
tek00015.png 29
tek00016.png 29.5
tek00017.png 30
tek00018.png 30.5
tek00019.png 31
tek00020.png 31.5
tek00021.png 32
tek00022.png 32.5
tek00023.png 32.8
tek00024.png 33
tek00025.png 33.2
tek00026.png 33.5
tek00027.png 34
tek00028.png 35
tek00029.png 36
tek00030.png 38
tek00031.png 40
tek00032.png 42
Power supply limit is 42 Amp

Assumed 10 MeV Setting

Energy set to close to 10 Region.


Energy switch changed to low energy setting. Part of the cavity is grounded.

Energy Switch Out (High En Range)
Dipole Coil Current
e- Beam Energy () MeV (estimate)
Solenoid 1 5.7 A
Solenoid 2 1.8 A
Gun Hor 0 A
Gun Ver 0 A
Output Hor -0.4 A
Output Ver 0.3 A
Rep Rate 30
Gun HV 10.0(Knob Setting)
Gun Grid Voltage 10.0 (Knob Setting)
RF frequency 2856.290 MHz
Modulator HV Power Supply 4.21 (Knob Setting)
RF macro Pulse Length (FWHM) 500 ns
Q1 (A) 0
Q2 (A) 0
Q3 (A) 0
Q4 (A) 0
Q5 (A) 0
Q6 (A) 0
Peak Current on FC 1 (45 deg) 42.8 mAmps
Peak Current on FC 2 (45 deg) 15.76 mAmps
Scope on FC 1 200 px
Scope on FC 2 200 px file name in flash drive is 10MeV_20A.png
Beam Spot 200 px


File Name in Flash Drive Dipole Coil Current (Amps)
tek00032.png 8
tek00033.png 9
tek00034.png 10
tek00035.png 11
tek00036.png 12
tek00037.png 13
tek00038.png 14
tek00039.png 15
tek00040.png 16
tek00041.png 17
tek00042.png 18
tek00043.png 19
tek00044.png 20
tek00045.png 21
tek00046.png 22
tek00047.png 23
tek00048.png 24
tek00049.png 25
tek00050.png 17.5
tek00051.png 18.5
tek00052.png 19.5
tek00053.png 20.5
tek00054.png 21.5
tek00056.png 22.5
tek00057.png 23.5

MeV Setting Energy with Switch on, Highest Mod HVPS (5.0 nob)

Energy switch turned on.

Dipole Set to MeV.


Energy switch changed to low energy setting. Part of the cavity is grounded.

Energy Switch Out (High En Range)
Energy with Switch on
Dipole Coil Current 20
e- Beam Energy () 10 MeV (estimate)
Solenoid 1 13.7 A
Solenoid 2 9.1 A
Gun Hor 0.5 A
Gun Ver 0 A
Output Hor 0.4 A
Output Ver 0.3 A
Rep Rate 30
Gun HV 10.0(Knob Setting)
Gun Grid Voltage 10.0 (Knob Setting)
RF frequency 2856.450 MHz
Modulator HV Power Supply 5.0 (Knob Setting)
RF macro Pulse Length (FWHM) 500 ns
Q1 (A) 0
Q2 (A) 0
Q3 (A) 0
Q4 (A) 0
Q5 (A) 0
Q6 (A) 0
Peak Current on FC 1 (45 deg) 42.8 mAmps
Peak Current on FC 2 (45 deg) 36.8 mAmps
Scope on FC 1 200 px
Scope on FC 2 200 px
Beam Spot 200 px


File Name in Flash Drive Dipole Coil Current (Amps)
tek00057.png 12
tek00058.png 13
tek00059.png 14
tek00060.png 15
tek00061.png 13.5
tek00062.png 14.5
tek00063.png 15.5
tek00066.png 16
tek00067.png 16.5
tek00068.png 17
tek00069.png 18
tek00070.png 19
tek00071.png 20
tek00072.png 21
tek00073.png 22
tek00074.png 23
tek00075.png 24
tek00076.png 25
tek00077.png 26
tek00078.png 27
tek00079.png 28
tek00080.png 29
tek00081.png 30
tek00082.png 31
tek00083.png 32


Energy switch turned on.

Dipole Set to MeV.


Energy switch changed to low energy setting. Part of the cavity is grounded.

Energy Switch Out (High En Range)
Energy with Switch on
Dipole Coil Current 15.3
e- Beam Energy () 10 MeV (estimate)
Solenoid 1 13.7 A
Solenoid 2 9.1 A
Gun Hor 0.5 A
Gun Ver 0 A
Output Hor 0.4 A
Output Ver 0.3 A
Rep Rate 30
Gun HV 10.0(Knob Setting)
Gun Grid Voltage 10.0 (Knob Setting)
RF frequency 2856.450 MHz
Modulator HV Power Supply 5.0 (Knob Setting)
RF macro Pulse Length (FWHM) 500 ns
Q1 (A) 0
Q2 (A) 0
Q3 (A) 0
Q4 (A) 0
Q5 (A) 0
Q6 (A) 0
Peak Current on FC 1 (45 deg) 42.8 mAmps
Peak Current on FC 2 (45 deg) 36.8 mAmps
Scope on FC 1 200 px
Scope on FC 2 200 px
Beam Spot 200 px


File Name in Flash Drive Dipole Coil Current (Amps)
tek000.png 15.3

Quad Test

Tune HRRL

Tune to following settings, observe beam. Check if there is mis-steering by quadrupole magnet.

This tune used for quad scan at Mar 17 2011, tuned 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 Scope image of good Accelarator setting by Dr. Kim Mar 17 2011.png
e- Beam Energy 14 MeV

Test mis-steering

Use OTR screen observe the beam. Turn all the quads off, except one at time. Change quad currents, see if mis-steering happens.

Quad Is there mis-steering? Beam images for different quad coil currents
Q1 200 px 200 px 200 px
Q2 200 px 200 px 200 px Q3 200 px 200 px 200 px
Q4 200 px 200 px 200 px
Q5 200 px 200 px 200 px Q6 200 px 200 px 200 px

Emittence Test (If time allows?)

Tune HRRL establish stable beam

1. Looking at the beam position on the screen and by the beam current on FC, try to align beam line. The goal is to center the beam on the screen, and maximize the FC charge as high as possible.

2. Reduced the mis-steering at the quadrupole by tuning steerers in the linac.

3. Optimize steerers, solenoids in linac to get a round electron beam shape and no steering at the quadrupole.

4. One good tune earlier for reference: [Tune HRRL]

10 MeV

Energy is set by bending the beam to dipole at specific current.

Set dipole current for 10 MeV, and bend the beam. Tune the beam energy, until we see peak current at the 45 degree Faraday cup.

Emittance measurement at 10 MeV

This is scan for 10 MeV beam. 40 mAmps peak current. Q1 is on, All other quads are off.

1) Scan from -5 Amps to 5 Amps. Increment at 0.2 Amps.

3) Name images by numbers start from 1. Then go on. Like: -5 Amp is 1, -4.8 Amp is 2, and so on til 5 Amp is named 51.

4) Scan multiple times from -5 to 5 Amps, and put them in different folders. Name folder by number, like 1, 2, 3 etc. After finishing one scan go back to -5 Amps. When going back take small steps (like 1 Amp), do not jump from 5 Amps to -5 Amps directly. After reaching back to -5, wait for few moment (like 10 s).

5) For each time, take back ground images. It should be done when RF is on and gun is off.

6) After the scan take a scope image for the current of the FC after the OTR screen. Lower the current, so the vacuum window do not heat up. This step is to check energy.

Emittance measurement at 16 MeV

Emittance measurement at 14 MeV

Emittance measurement at 4 MeV