From c0885d47b7993849f80aa31ee3e1c53e2deef7f1 Mon Sep 17 00:00:00 2001 From: watts Date: Thu, 2 May 2024 15:19:09 +0200 Subject: [PATCH] Update SOPHIE Alignment --- SOPHIE-Alignment.md | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/SOPHIE-Alignment.md b/SOPHIE-Alignment.md index 1b5c361..ad08d63 100644 --- a/SOPHIE-Alignment.md +++ b/SOPHIE-Alignment.md @@ -40,8 +40,30 @@ In this design the virtual drift is determined by the long reference mirrors in | ![Ref_Mirror_combi_view](uploads/d38a778a85914474d4493113f1d3fd23/Ref_Mirror_combi_view.jpg) | |:--:| -| Figure 3. Design drawings and 3D render of the reference mirrors. The [alignment screws](https://www.thorlabs.com/thorproduct.cfm?partnumber=P25SB100V) ([P25SB100V](uploads/48b6c202c417e8f890c64728ddda7d4a/P25SB100V-AutoCADPDF.pdf)) have a thread of 1/4''-100 and so each full turn will change the local mirror height by XX. | +| Figure 3. Design drawings and 3D render of the reference mirrors. The [alignment screws](https://www.thorlabs.com/thorproduct.cfm?partnumber=P25SB100V) ([P25SB100V](uploads/48b6c202c417e8f890c64728ddda7d4a/P25SB100V-AutoCADPDF.pdf)) have a thread of 1/4''-100 and so each full turn will change the local mirror height by 25.4 microns (clockwise to raise mirror face). Turning the 2 upper screws by a full turn in opposite directions will adjust the tilt of the mirror by 0.282 mrad. | ## Fixing the SOPHIE Alignment +### Characterise the Virtual Drift +1. Ensure that no software drift correction is being applied by checking the values of zCorrectMatrix in the [Orocos Deployer](https://gitlab.psi.ch/microspectro/pixelator/-/wikis/Running-Orocos) and then setting both elements to zero: +``` +Sensor1.zCorrectMatrix[0] = 0.0 +Sensor1.zCorrectMatrix[1] = 0.0 +``` +2. Open the interferometer EPICS panel to see the raw outputs from the J/K interferometers before they are translated into X/Y positions. These values will be in terms of fringes and can be interpreted in microns by multiplying by the sensor resolution factor set in [`start.ops`](https://gitlab.psi.ch/microspectro/pixelator/-/blob/master/PixelatorRealtime/startup/SIM/start.ops?ref_type=heads#L45) (0.0001545388). (Alternatively, turn off the transformation by setting `Sensor1.transform=0` in [`start.ops`](https://gitlab.psi.ch/microspectro/pixelator/-/blob/master/PixelatorRealtime/startup/SIM/start.ops?ref_type=heads#L49), which will also disable the software drift correction). +3. Switch off the sample stage feedback by jogging the coarse sample stage. +4. Note the interferometer values and ZP-Z position. +5. Move the ZP-Z stage by a defined amount. +6. Note the new interferometer values and ZP-Z position. +7. Calculate the effective mirror tilts of the J and K interferometer reference mirrors. +8. Calculate the number of screw turns required to remove the calculated tilt from the reference mirrors. + +### Fix the Virtual Drift + +Apply the calculated screw turns to make the reference mirror parallel and then further adjust the interferometer components to compensate the beam alignment and optimise the signal strength. + +### Characterise and Fix the Real Drift (Requires X-rays) + + +