Beam Test Apr 26 2012

Preparation

[Check List]

12 MeV Setting

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

Energy Switch	In (Part of the cavity is grounded, HRRL low energy operation mode )
e- Beam Energy ()	12 MeV
Solenoid 1	A
Solenoid 2	A
Gun Hor	A
Gun Ver	A
Output Hor	A
Output Ver	A
Gun HV	(Knob Setting)
Gun Grid Voltage	(Knob Setting)
RF frequency	3 MHz
Modulator HV Power Supply	(Knob Setting)
RF macro Pulse Length (FWHM)	ns
Q1 (A)	0
Q2 (A)	0
Q3 (A)	0
Q4 (A)	0
Q5 (A)	0
Q6 (A)	0
Peak Current on FC	mAmps
Scope on FC	File:Hrrl 26Apr2012 EnTest 4MeV FC cur.png
Beam Spot	File:Hrrl 26Apr2012 EnTest 4MeV beam im.png

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.

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		File:Hrrl 24Apr2012 QTest q1 1Amp.png File:Hrrl 24Apr2012 QTest q1 3Amp.png File:Hrrl 24Apr2012 QTest q1 5Amp.png
Q2		File:Hrrl 24Apr2012 QTest q2 1Amp.png File:Hrrl 24Apr2012 QTest q2 3Amp.png File:Hrrl 24Apr2012 QTest q2 5Amp.png	Q3		File:Hrrl 24Apr2012 QTest q3 1Amp.png File:Hrrl 24Apr2012 QTest q3 3Amp.png File:Hrrl 24Apr2012 QTest q3 5Amp.png
Q4		File:Hrrl 24Apr2012 QTest q4 1Amp.png File:Hrrl 24Apr2012 QTest q4 3Amp.png File:Hrrl 24Apr2012 QTest q4 5Amp.png
Q5		File:Hrrl 24Apr2012 QTest q5 1Amp.png File:Hrrl 24Apr2012 QTest q5 3Amp.png File:Hrrl 24Apr2012 QTest q5 5Amp.png	Q6		File:Hrrl 24Apr2012 QTest q6 1Amp.png File:Hrrl 24Apr2012 QTest q6 3Amp.png File:Hrrl 24Apr2012 QTest q6 5Amp.png

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.