Revision as of 19:30, 6 July 2012

Vacuum Leak Issue

On Friday (29Jun2012) vacuum is at 23.5 mtorr.

Removed one problem gaskit, vacuum at 20 mtorr (with turbo on). The gaskit is at the end of the 45 deg bellow.

Fixed snapped bolt at the end of the 90 deg, with roughing pump, vacuum is 2.55 torr.

Check and Fix on Monday the July 2nd

Vacuum was fine until energy slits. We put blank-off after energy slits, then pulled the vacuum, vacuum pressure was low enough to light up the filament. This indicates energy slit is well sealed.

We pulled the vacuum just on 5-way cross without the top flag, and with short bellow and the short beam pipe myles made, there was a leak. Engineers suspects it was the pipe Myles made leaking. Kevin will redo the pipe.

We pulled the vacuum on 2nd dipole connected to 90 degree beam line until the end of 3rd triplet

Beampipe myles wielded was fixed, and placed to beamline fortesting by engineers. This beampipe was tested along with energy slits.

Vacuum wentdown to 8 mtorr range. When alcohol sprayed on the of the energy slits, there jump on the vacuum, then it was sealed with vacuum sealing liquid, vacuum went down to 4 mtorr.

It was suspected that energy Slits were the problem. End of Energy slits was sealed and tested, vacuum went down to lower ten to minus 5 torr range. Energy slits are good.

The gasket at the end of the energy slit were not well centered, and dent on the gasket was not good. So this could be the source of leak.

Test was also done on from 2nd dipole and 90 deg beam line until the end of the 3rd triplet, vacuum went down to 3 time 10 to the minus 5 torr.

5 way cross with flag on it along with Myles's pipe removed and Tested, vacuum went down to 3*10^(-5). The were good.

Myles's long beampipe that goes through the wall was tested, it went down to 2*10^(-5) torr. It was good.

Test was done all the beam parts except long beampipe goes through the wall. Vacuum went down till 3*10^(-5) torr range. Vacuum is good.

Conclusions

1. Major leak was on the beampipe made by Myles.

2. There are minor leaks with misplaced gaskets. One at the end of the 3rd triplet, one is at the end of 2nd dipole.

Later Observations

After 2hours the vacuum is down to 3*10^(-6) torr.

The next (July 3rd) day morning vacuum went down to 5*10^(-7) torr. Then turned up ion pump, left ion pump along with turbo. In the afternoon, sucking station removed, ion pump was pumping. The pressure was at 10^(-7) range.

On July 4th, the vacuum is at 5.6 * 10^(-7) range.

Preparation

[Check List]

1. Magnets: Hock up q7 and D2. Check Q8-11.

2. Camera: (a) Check if Working, shielding good, Sync? Cam 2 for 45 flag.

3. Flags: Hock up and check if working

4. Farady Cup: All 3 hocked up?

6. Gas bottle for valve full? --

7. Gas bottle for flags full? --

8. 3 Pickup Coils (Green Torroids):

9. Energy slit working?

Run Plan (Goal)

General goals are:

1. To find settings for different energies.

2. To find out each beam elements are working properly.

3. Deliver the beam to 0 degree, then 45 degree and 90 degree beamline. Observe them with Faraday cup at 0, 45 and 90 degrees and record settings.

Run list

Do the following for different energies. Start from 10 MeV, the do 3 MeV, then Do 15 MeV etc.

1. Deliver the beam to 0 degreebeamline

Use 0 deg Faraday cup to observe electron beam current.

2. Deliver the beam to 45 degree beamline

1. Observe the beam using Energy slits' two jaws.

2. Observe the beam using 45 degree Flag with YAG target.

3. Observe the beam using 45 deg Faraday cup.

4. Change the width of the slits and see the change in the slit jaw currents and 45 Faraday cup signals.

3. Deliver the beam to 90 degree beamline

Use 90 deg Faraday cup to observe electron beam current.

Energy Scan at 15 esh MeV

[Dipole Map]

1. Tuning

Energy Switch	Out (High En Range)
Dipole Coil Current
e- Beam Energy ()	MeV (mapping )
Solenoid 1	12.9 A
Solenoid 2	13.7 A
Gun Hor	0.1 A
Gun Ver	0 A
Output Hor	-0.5 A
Output Ver	0.0 A
Rep Rate	30
Gun HV	10(Knob Setting)
Gun Grid Voltage	7.24 (Knob Setting)
RF frequency	2856.291 MHz
Modulator HV Power Supply	4.84 (Knob Setting)
RF macro Pulse Length (FWHM)	200 ns
Q1 (A)	0
Q2 (A)	0
Q3 (A)	0
Q4 (A)	0
Q5 (A)	0
Q6 (A)	0
Peak Current on FC 1 )	60 mAmps
Peak Current on FC 2	mAmps
Scope on FC 1	200 px
Scope on FC 2	200 px
Beam Spot

Energy Scan at Low Energy 8 MeV esh

1. 1st Tuning

Energy switch is in, linac operates at low energy

Energy Switch	In (Low En Range)
Dipole Coil Current
nominal e- Beam Energy ()	MeV (mapping )
Solenoid 1	12.1 A
Solenoid 2	9.6 A
Gun Hor	+ 0.2 A
Gun Ver	0 A
Output Hor	+ 0.2 A
Output Ver	+ 0.1 A
Rep Rate	30
Gun HV	8.97(Knob Setting)
Gun Grid Voltage	9.96 (Knob Setting)
RF frequency	2856.289 MHz
Modulator HV Power Supply	4.185 (Knob Setting)
RF macro Pulse Length (FWHM)	200 ns
Q1 (A)	0
Q2 (A)	0
Q3 (A)	0
Q4 (A)	0
Q5 (A)	0
Q6 (A)	0
Scope on FC 1	99.2 mA 200 px
Scope on FC 2	200 px
Beam Spot

2. 2nd Optimizing Magnets