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Progress of Shintake Monitor Work

Progress of Shintake Monitor Work. October 7, 2009 T. Yamanaka. New Laser. Laser Installation. The new laser was delivered on September 24. Laser Head. Power Supply Box. Laser Installation. The new laser was put on the current optical table.

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Progress of Shintake Monitor Work

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  1. Progress of Shintake Monitor Work October 7, 2009 T. Yamanaka

  2. New Laser

  3. Laser Installation • The new laser was delivered on September 24. Laser Head Power Supply Box

  4. Laser Installation • The new laser was put on the current optical table. • The old laser was put on the additional table in the extended laser hut. New Laser Old Laser

  5. Laser Setup • Engineer from laser company • Installation of SHG • Connection of N2 flow line at the laser head • Filling up of internal cooling water • Measurement of laser parameter • Power • Profile • Waveform • Timing jitter

  6. Laser Power • Specification • 2500mJ/pulse @ 1064nm • 1500mJ/pulse @ 532nm • Measured • 2300mJ/puse @ 1064nm （with SHG unit） • 1510mJ/pulse @ 532nm （Spolarization） • 1360mJ/pulse @ 532nm （Ppolarization, at first） • 1220mJ/pulse @ 532nm （Ppolarization, later） • Power is reduced by 10-20 % when the polarization is changed at the harmonic generation.

  7. Laser Profile • Measured the split laser light by CCD camera • Laser was operated with full power. • A focusing lens was used (laser width is large). cf ) old laser Measured at the laser company (don’t focused) Spolarization Ppolarization

  8. Laser Waveform • Used a PIN-photodiode and an oscilloscope to see the laser light waveform. Seeded Unseeded • 1 DIV = 5ns • Pulse width (FWHM): 8-9 ns with seeded laser

  9. Timing Jitetr • Measured the time interval of • Q-Switchtrigger (internal clock, 6.25 Hz) • laser light （measured by PIN-photodiode） cf ) Old laser RMS = 409 ps have tail RMS = 258 ps Gaussian-like distribution

  10. Issue • Polarization • There is a way to change the polarization on the optical table by mirror reflection. • Pressure of external cooling water is not enough. • Now operate with cancelling the water pressure interlock • Need to test the cooling power of the chiller Polarization

  11. Trouble: Damage to SHG • Operate the laser with us in next week of installation • Bad profile was observed（get chipped） • Found damages to SHG when opening the SHG unit • Laser power was bit decreased. • 1090mJ/pulse @ 532nm （Ppolarization） • 1220mJ/pulse @ 532nm （Spolarization） Sketch of laser profile Polarization Plate SHGcrystal

  12. Cooling Power of Chiller • Checked the cooling power of chiller is enough or not, even if the water pressure is not enough. • It was dangerous to use SHG (because of damage to it), used fundamental wave (1064nm) • Measured the temperature of internal cooling water and the laser power. • Used Long Pulse Mode（several hundred us pulse width)

  13. Result of Measurement Temperature Ch1(blue) : Water IN Ch2(yellow) : Water OUT • Out temperature exceeds 30 deg C but very stable right after the laser on • Laser power is also stable Laser power • It seems to be enought with the present chiller. • will discuss with the engineer of the laser company.

  14. Phase Stabilization

  15. Phase Stability • The drift of the laser phase was observed in long-term measurement. • The correlation of laser light position (angle) and the laser phase was measured. • The drift of the laser position was also measured. • Will the laser phase be stabilized by stabilizing the laser position?

  16. Feedback Stabilization of Position PSD2 Mirror with actuator-2 Mirror with actuator-1 PSD1

  17. Stabilization of Laser Position with stabilization without stabilization • Long-term drift was stabilized • Shot-term oscillation (several tens of minutes) cannot stabilized.

  18. Phase Stability • It seems the drift happens at the beginning of the measurement (not DAQ, but the laser light is introduced) • Also people are around the IP area • However, the drift of the laser phase is not disappeared even if the laser position was stabilized. Phase measurement during the position stabilization Example of phase measurement without position stabilization

  19. IP Target Installation

  20. IP Target Insertion Stage • Attached on the IP vacuum chamber • Vacuuming test • No leak was found with vacuum pumped with a rotary pump (2x10-4Pa) • Stage work normally after the vacuuming

  21. Assembling of IP Target (1) • Fabrication of the target holder has been finished. • Assembling Knife edge target for the laser size measurement at the IP

  22. Assembling of IP Target (2) • Screen monitor (almina fluorescent plate) for 174 deg and 2 - 30 deg mode 174 deg mode plate can be seen from the reverse side 0.1mmthick almina plate

  23. Assembling of IP Target (3) • Attach Φ10μmtungsten wire at the tip of the holder Nilaco tungsten wire • Stretch the wire and fixed on the holder by soldering • 3 wires, around 2 mm interval

  24. Installation of Target Holder • Attach the assembled holder to the mover shaft Shaft of mover

  25. Alignment of Target • Put a rotating laser just upstream of Final Doublets and pass through the laser light in the beam pipe to simulate the electron beam path • Hit the laser light on the screen monitor and adjust the mover axis so that the light is centered on the screen monitor. • Adjust the CCD camera position so that the light is centered on the image of screen. • Adjust the focusing and the magnification of camera lens. Before adjustment After adjustment

  26. Calibration of Axis • After the alignment, checked the horizontal/vertical axis on the screen. screen for 174 deg mode screen for 2 - 30 deg mode Horizontal 52 deg Horizontal 52 deg Vertical Vertical

  27. Regarding Gamma-ray Detector

  28. Gamma-ray Shutter • It is desired HVs to the Gamma-ray detector are supplied even if screen monitors and wire scanners are inserted. • By blocking the collimator hole with lead blocks, shield the detector from a large amount of gamma rays from screen monitors.

  29. Gamma-ray Shutter • Take out and put in 50x50x200mm lead block in front of collimator • Can control remotely Move Direction Gamma Ray

  30. Layout around Detector DUMP Movable Collimator in H & V Lead, Φ10 or Φ16, 200 mm thickness Movable Shutter 50x50mm, 200 mm thickness lead block Cherenkov Detector (locally movable) Wider chamber BDUMP CsI(Tl) Calorimetor Lead block shield Cherenkov Detector for Wire Scanner Rear Collimator Lead, Φ20, 200 mm thickness Front Collimator Lead, Φ20, 200 mm thickness Movable Background Monitor (Plastic Scintillator with lead plate)

  31. Detector Interlock • By using gamma-ray shutter, interlock to guard the detector from the large amount gamma rays become simple. • can be done with hardware • reverse interlock won’t be needed contact / noncontact signal Screen Monitor Wire Scanner IN INTERLOCK HV Module IN Gamma-ray Shutter

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