m. attal, 10 th technical advisory committee meeting, may 10-11, 2010, allan, jordan...

M. Attal, 10th Technical Advisory Committee Meeting , May 10-11, 2010, Allan, Jordan

Synchrotron-light for Experimental Science and

Applications in the Middle East

Maher Attal

On behalf of

The CommissioningTeam

The Full Energy Microtron and TL1 Commissioning

&Future Plan for the Microtron




The Microtron Commissioning Conditions

The Safety Procedures Taken

The microtron is shielded by the permanent machine shielding wall. The booster hall door is interlocked with switch connected to the PLC.

The microtron in interlocked if a one-second dose rate exceeds 6µS/h or if the accumulated dose exceeds 10µS/session.

3 flasher lights are used for alarming.

Triggering the microtron just after inspecting the locations of the commissioining staff.

The personal gamma dosimeters are measured before and after each session. Whereas the Neutron TLDs are measured by Jordan Atomic Energy Commission (JAEC) each 3 months.

1




The diagnostic tools used The gun current signal: indicates the current emission from the cathode. The magnetron current signal: indicates the operation status of the magnetron.

Reflected Power signal: indicates the status of beam acceleration.

Deflection Tube signal: indicates the passge of the beam through deflection tube.

BCM signal: indicates the exit of electron beam to the transfer line (TL1).

The FOM signal: shows the size position and intensity of the beam.

Faraday cup signal: measures the beam current value.

The FCT (recently used) signal: measures the beam current value.

The vacuum pressure was ≤ 1 x10-6 mbar in microtron and TL1.

2

3




The Full Energy Microtron Commissioning without Transfer Line (The FOM and FC were installed directly at the microtron exit)

The strategy to get the full energy beam was: - to get back the low energy beam first (after 10 months of shutdown), - then to go up the next orbit, - make fast optimization for the beam, - then move to the higher orbit

Commissioning session # 1 (15 Nov. 2011):

short circuit in the deflection tube switch limit & malfunction in the trigger signal The session was closed without beam




Commissioning session # 2 (17 Nov. 2011): Using the old settings (10 months ago) but varying a little bit the Gun Axial position:

We got a strong beam from the 1st orbit (assumed E ~ 5.4 MeV)

Going up to the next orbits & optimizing the beam intensity using the Trim Coils (TC1, TC2, TC3 & TC4):

We got the beam from the 12th orbit (assumed E ~ 12.5 MeV)





- We started with the settings of the last session and got the beam @ orbit 12.

- By playing with some parameters like: TCs current values, gun axial position, and RF frequency (the main magnetic field was varied also a little bit)

we got the beam from the final orbit 42 (assumed E ~ 22.5 MeV ???)





- The settings of the last session were used.- The aim of this session was: * Check the reproducibility of the beam * To measure the current using the FC * To measure the radiation dose at different locations - The beam didn’t show up from the first shot (the reason could be varying the main magnet field in the last session). By varying the values of TCs slightly (mainly TC2)

we got the beam - The beam intensity was more enhanced by varying the gun axial position- The beam was centered on the FOM screen using TL1 correctors STX1, STY1.




Commissioning session # 5 (1 Dec. 2011):

- The settings of the last session were used.- The aim of this session was: Check the reproducibility of the beam To investigate the spark interlock & beam stop prblem To measure the radiation dose at different locations

we got a strong beam from the first shot

we found that: - lower gun current set value: higher beam intensity but lower time of continous beam emission (spark interlock signals fires earlier).- The beam full dimenstions are: horizontal size = 3 mm vertical size = 14 mm




CORR1x,y

CORR2x,yCORR3x,yCORR4x,y

FOM

Triplet2

Triplet1

The Full Energy Microtron Commissioning with Transfer Line (after 3.5 months of shutdown)




Commissioning session # 1 (18 March 2012):

- The settings of the last session were used.- We couldn’t get a signal from Deflection Tube (DT), but constant noise signal.

No beam was obtained

Commissioning session # 2 (short session):

- We investigated the source of the bad DT signal: The DT signal coaxial cable was disconnected from the corresponding rack.




Commissioning session # 3:

- Although all the obtained signals indicated the exit of the beam, however we couldn’t see the beam on the FOM screen.- We found a strong vertical misalignment in the TL1 and asked for re-alignment.

Commissioning session # 4 (27 March 2012):- TL1 is re-aligned.- STX1, STY1 are ON with the same old value, while other TL1 steerers are OFF.- The two triplets are ON with 1 A in the outermost quads and 2 A in the middle one. - In spite of the good promissing signals, no beam was seen.- By turning on STY2 and playing with it,

the beam showed up.




- The steerers and Triplets’ quadrupoles were used to guide the beam through the Triplets magnetic centers (Beam Based Alignment).

- The two triplets were used to focus the beam till

we got a god shape. - The corresponding current values are: TC1 = 0.759 A, TC2 = -0.431 A, TC3 = 0.129 A, TC4 = -0.017 A STX1 = 0.718 A, STY1 = -1.371 A STX2 = 0.890 A, STY2 = -0.799 A STX3 = -1.499 A, STY3 = -1.200 A STX4 = not used, STY4 = not used

Triplet 1: QD = 0.336 A, QF = 1.250 A Triplet 2: QD = 0.625 A, QF = 2.292 A

3 mm

4.4 mm




Commissioning session # 5 (29 March 2012):- The settings of the last session were used

The beam was obtained from the first shot

Failure in the Transistors of MMPS happened & the session was stopped.

Commissioning session # 6 (4 April 2012):- The settings of the last session were used- By some variation to the TC currents the beam showed up. This indicates a variation in the main field due to transistor replacement




Rough Measurement to the Beam Energy

- Integrated magnetic field of STY3 was measured for I = 1 A, BL = 123.68 mT.cm.

- Distance of steerer 3 center from that of FOM screen was measured, d = 545 mm.

Commissioning session # 7 (25 April 2012) - The beam was centered to the Triplets magnetic centers & the FOM screen center using steerers 1 & 2 while steerer 3 was kept OFF.

- The beam y-displacement was measured versus STY3 current

E (MeV) <I * 123.68e-2 *0.299792458 *545/ y > = < 20.8 + 21.7 + 23 +22.5> = 22 MeV

STY3 current (A) -0.54 -1.64 0.54 1.64

Beam y-displacement (mm) -5.25 -15.25 4.75 14.75




Increasing Energy of the Microtron Output Beam Commissioning session # 8 (16 May 2012):

- The beam was obtained after some adjustment to the TC currents.- We increased the main magnetic field by changing the potentiometer set value from 6.0 to 6.4.

We gained one more orbit without loosing the beam (i.e. E ~ 22.5 MeV)

- By turning the main magnet OFF & ON (recycling the main magnet)

the beam was obtained by adjusting the TC currents.




Measuring the Microtron Beam Current Value

- An FCT (from ANKA) is installed at the end of TL1.

Commissioning session # 9 (23 May 2012)

(after 4 months of Microtron shutdown)

- The settings of the last session were used.- By doing some adjustment to the TC currents

The beam was obtained




- The DT & FCT signals were optimized using the TC and gun axial & angular positions.

- The maximum obtained width of FCT signal was 1.3 µs.- Width of DT signal is always 2 µs.- The max. measured current value ~ 8 mA (FCT calibration factor = 2.5 ).




Control GUIs of the Microtron, Trim Coils & FOM




Control GUIs of TL1 Correctors & Triplets




Frequently Faced Problems

Failure in transistors of the Main Magnet Power Supply.

Short circuit in the deflection tube switch limits.

Coupling and non-reproducibility in the axial and angular movements of electron gun.

Misleading and non-reproducible DT position reading




Future Rehabilitation Steps on Microtron System

Replacing the old power supplies by new ones Mainly: MMPS

Replacing the old modulator by solid state one.

Reducing the microtron racks by as much as possible. (Two are already removed, and two still need to be removed)

Replacing the gun old DC motors by new stepper motors.

Remotly controlling / monitoring new signals which are not done before.

1

2

3

4

5




Thank you

m. attal, 10 th technical advisory committee meeting, may 10-11, 2010, allan, jordan...

Documents