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

New Laser

Laser Installation The new laser was delivered on September 24. Laser HeadPower Supply Box

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

Laser Installation Wiring to power supply – AC200V cable – External cooling water – Interlock terminal Wiring to laser head – Electric/signal cable – Internal cooling water – N 2 flow line

Laser Setup Engineer from laser company – Installation of SHG – Connection of N 2 flow line at the laser head – Filling up of internal cooling water Measurement of laser parameter – Power – Profile – Waveform – Timing jitter

Laser Power Specification – 1064nm – 532nm Measured – 1064nm （ with SHG unit ） – 532nm （ S polarization ） – 532nm （ P polarization, at first ） – 532nm （ P polarization, later ） Power is reduced by % when the polarization is changed at the harmonic generation.

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). S polarizationP polarization Measured at the laser company (don’t focused) cf ) old laser

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

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

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

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. – 532nm （ P polarization ） – 532nm （ S polarization ） Sketch of laser profile SHG crystal Polarization Plate

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)

Result of Measurement 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 Temperature Laser power It seems to be enought with the present chiller. will discuss with the engineer of the laser company.

Phase Stabilization

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?

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

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

Phase Stability 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 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

レーザートランスポート Extraction Laserwire グループのレーザーを 引いてくるためのトランスポートライン の製作 新竹モニタ側トラ ンスポート用架台 トランスポートライン途 中 （内径 100mm の塩ビパイ プ） EXT LW 側トランスポー ト用架台

IP Target Installation

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

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

Assembling of IP Target (2) Screen monitor (almina fluorescent plate) 0.1mm thick almina plate for 174 deg and deg mode 174 deg mode plate can be seen from the reverse side

Assembling of IP Target (3) Attach Φ10μm tungsten wire at the tip of the holder Stretch the wire and fixed on the holder by soldering 3 wires, around 2 mm interval Nilaco tungsten wire

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

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 adjustmentAfter adjustment

Calibration of Axis After the alignment, checked the horizontal/vertical axis on the screen. screen for 174 deg modescreen for deg mode Vertical Horizontal 52 deg Horizontal Vertical 52 deg

Regarding Gamma-ray Detector

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.

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

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

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 Screen Monitor Wire Scanner Gamma-ray Shutter HV Module IN INTERLOCK contact / noncontact signal

ビーム軸アライメント Final Doublet のアライメントが行われた – 上流のマグネットから線を引いて一直線に並 べる – 新竹モニタ定盤で、南側に 3mm ビーム軸がず れた – これに合わせてチェンバーを移動

検出器アライメント ローテーティングレーザーでビーム軸の 水平方向、垂直方向の線をケガき、それ に合わせてディテクタ関連を置いた 水平方向軸出し アライメントされた Final Doublet を基 準に 垂直方向軸出し ビーム軸より 375mm 高い場所を回す

Detector Alignment Front Collimator Gamma-ray Shutter CsI(Tl) Detector and Background Monitor