1. Southeastern Louisiana University / LIGO Livingston 1 Modeling the Input Optics using E2E R. Dodda, T. Findley, N. Jamal, K.Rogillio, and S. Yoshida, Southeastern Louisiana University – Acknowledgement – LIGO Livingston Observatory, SURF 2004, NSF B. Bhawal, M. Evans, V. Sannibale, and H. Yamamoto

2. Southeastern Louisiana University / LIGO Livingston 2 Objectives A simulation model will be very convenient to study the impact of ground motion on the input optics, and on the input beam. Therefore, we seek to do the following: 1. Build an IO box using E2E ( time domain). 2. Integrate it with the Simligo. 3. Run simulation with real-time ground motion.

3. Southeastern Louisiana University / LIGO Livingston 3 The IO and Simligo boxes

4. Southeastern Louisiana University / LIGO Livingston 4 The Process 1.Make a Small Optic Suspension (SOS) box, and validate it. 2.Use the SOS box to damp the motion of an optic when real-time ground motion is given. 3.Create a Mode Cleaner (MC) box, and try to lock the cavity when real-time ground motion is given to the Mode Cleaner optics. 4.Put all the optics ( MCs, SM, and MMTs ) in order, and create the Input Optic (IO) box. 5.Use the IO box in Simligo, and run the simulation for the entire detector.

5. Southeastern Louisiana University / LIGO Livingston 5 Validating SOS – Role of the Table Top motion MC1 Yaw motion using two different schemes Schematic diagram of the SOS box with HAM motion as input

6. Southeastern Louisiana University / LIGO Livingston 6 HAM stack box  dt ACCX X in Y in Table u Table v )( 0 )( 0 2211 ),(,),( xktiykti eAtxveAtyu    )( 21  kkk  Table yaw = )},(),({ 2 1 )( 2 1 21 txviktyu x v y u       )},(),(){(txvtyuki  HAM table Vibration isolation stacks Accelerometer Calculating the HAM table’s yaw U V q

7. Southeastern Louisiana University / LIGO Livingston 7 Dependence of k on frequency

8. Southeastern Louisiana University / LIGO Livingston 8 Calculating the suspension point motions of the optics u(x,y)= U - y v(x,y)= V + x U: table’s center of mass translational motion V: table’s center of mass translational motion : table’s yaw motion U V q MMT3 (-0.8, 0.6) (0, 0) MC3 (0.75, -0.05) MC1 (0.75, -0.25) SM (0.75, 0.45) MMT1 (0.1, 0.4)

9. Southeastern Louisiana University / LIGO Livingston 9 MC2 and MC3 MC2 Pend MC2 Yaw MC3 Pend MC3 Yaw

10. Southeastern Louisiana University / LIGO Livingston 10 Damped MC1 pendular motion

11. Southeastern Louisiana University / LIGO Livingston 11 Mode Cleaner box – Preliminary Results

12. Southeastern Louisiana University / LIGO Livingston 12 Conclusions l HAM table motion estimated from the ACC[XY] DAQ signal l MC1, MC3 local damping optimized l MC box constructed and being tested l Combination of MC and IFO in progress