1. Soft X-ray Telescope X-ray mirrors and CCD detectors By S.Amruthavalli Under the guidance of Prof. K.P.Singh DAA

2. My Project Fabrication of X-ray mirrors: Sputtering Interfacing RAM with FPGA.

3. Contents of Presentation Introduction X-ray mirrors  Theory of X-ray reflection  Process of fabrication  Sputtering CCD Detectors  Introduction to CCD  FPGA  Interfacing RAM and FPGA References

4. Introduction SOFT X-RAY TELESCOPE ( SXT): SXT is one of the scientific instruments onboard ASTROSAT. A grazing incidence X-ray Telescope  Mirror assembly  X-ray CCD at the focus.

5. Theory of X-RAY Grazing Incidence Reflection n = 1 - d - ib d = N o Zr e p λ 2 A 2π By Snell’s Law cos α t = 1-d (α t is the grazing angle) For d<<1, α t = √2d If Z/A ~ 0.5 then α t = 5.6 λ √ p

6. Wolter I type configuration

7. Theory of X-RAYs (contd.) Imaging of X-rays: Conical Approximation to Wolter type I: Paraboloid (1-alpha) + Hyperboloid (3-alpha)

9. SXT: A Schematic Overview

10. X-RAY Mirror Fabrication STEP 1 : Substrate formation

11. X-RAY Mirror Fabrication STEP 2 : Glass Coating

12. X-RAY Mirror Fabrication STEP 3 : Replication

13. X-RAY Mirror Fabrication STEP 3 : Replication (contd.)

14. SPUTTERING

15. SPUTTERING (contd.) A DC Sputtering system

16. SPUTTERING (contd.) Some important aspects: 1)Argon gas 2)Pressure Range : 30-120 mtorr 3)Voltage range : 500V to 5000V

17. CCD detector  EEV CCD22 IMAGE REGION: Imaging area : ~ 2.4 X 2.4 cm. 600 X 602 array of 40µm X 40µm pixels STORAGE REGION: 600 X 602 pixel array of 39 X 12µm pitch. OPERATING MODE: Photon counting mode

18. Schematic of CCD

19. SXT Electronics Block Diagram

20. FPGA: Actel ProAsic Plus APA150 General Structure

21. Interfacing RAM with FPGA  Need?  FPGA used: Actel ProAsic Plus APA150.  RAM used: HM6264 (8k)  Need for buffer and Latch

22. Hardware circuit

23. Softwares used Microcontroller: Programming MC: Labtool FPGA: Program: Libero (Verilog HDL) Hardware: PROTEL DXP Programming FPGA: Actel Flash pro

24. CONCLUSION 1) I was involved in sputtering of 15 glass mandrels out of which in 9 the gold was transferred successfully onto Al foils. 2) RAM was first interfaced with Microcontroller. The hardware and software was tested. Later the program was adopted for FPGA using Verilog HDL and the hardware was designed in PROTEL.

25. REFERENCES  B Aschenbach in “Reports of Progress in Physics” (1985).  Report on “Laboratory X-ray CCD camera electronics” by Department of Astrophysics, The Pennsylvania State University.  “Glow Discharge Process” by Brian Chapman

26. Acknowledgements I am extremely grateful to Prof K.P. Singh for his invaluable guidance. I am obliged to have worked under him encouraged me to do develop a pragmatic approach to whatever I do. I also wish to thank Ms. Nisha Yadav who patiently taught me the process of X-ray mirror fabrication. I am thankful to Mr. Dinesh Gupta who helped me through out in the electronics part. I am also thankful to Mr. Irfan who helped me debug the programs.

27. THANK YOU