Beam Test Apr 26 2012
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
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 | 0 A |
| Solenoid 2 | 0 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 |
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 | 
|
| 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.