1. 1 Jennifer L. Loos jloos@slac.stanford.edu 1 SULI Presentation August 13, 2009 Design and Implementation of a Thermal and Acoustic X-ray Detector to Measure the LCLS Beam Energy Jennifer L. Loos August 13, 2009

2. 2 Jennifer L. Loos jloos@slac.stanford.edu 2 SULI Presentation August 13, 2009 LCLS Accelerator Schematic SLAC linac tunnel research yard Linac-0 L =6 m Linac-1 L  9 m  rf   25° Linac-2 L  330 m  rf   41° Linac-3 L  550 m  rf  0° BC1 L  6 m R 56   39 mm BC2 L  22 m R 56   25 mm DL2 L =275 m R 56  0 DL1 L  12 m R 56  0 undulator L =130 m 6 MeV  z  0.83 mm    0.05 % 135 MeV  z  0.83 mm    0.10 % 250 MeV  z  0.19 mm    1.6 % 4.30 GeV  z  0.022 mm    0.71 % 13.6 GeV  z  0.022 mm    0.01 % Linac-X L =0.6 m  rf =  21-1 b,c,d...existing linac L0-a,b rfgun 21-3b24-6d X 25-1a30-8c Courtesy of Paul Emma

3. 3 Jennifer L. Loos jloos@slac.stanford.edu 3 SULI Presentation August 13, 2009 Courtesy of J. Welch and D. Schultz

4. 4 Jennifer L. Loos jloos@slac.stanford.edu 4 SULI Presentation August 13, 2009 Current Diagnostic Used to Measure Beam Power Total Energy (Thermal) Sensor uses a suite of thermal sensor arrays Located in Front End Enclosure (FEE) Courtesy R. Bionta

5. 5 Jennifer L. Loos jloos@slac.stanford.edu 5 SULI Presentation August 13, 2009 Courtesy of J. Welch and D. Schultz

6. 6 Jennifer L. Loos jloos@slac.stanford.edu 6 SULI Presentation August 13, 2009 Beam Dump Area Vacuum Chamber ST0 Electronics go here Old Vacuum Chamber New Vacuum Chamber

7. 7 Jennifer L. Loos jloos@slac.stanford.edu 7 SULI Presentation August 13, 2009 Concept For Design “ Radiation acoustics is a field of physics in which sound phenomena arising under radiation interacting with matter are studied. ” So, the idea is to have a target material placed in the beam line, and by measuring the acoustic wave produced in the material, the power can be determined. How is the wave detected and measured?

8. 8 Jennifer L. Loos jloos@slac.stanford.edu 8 SULI Presentation August 13, 2009 Mechanical stress on some materials (in this case ceramic), can generate an electric potential which then creates a voltage across the material. PiezoelectricEffect Source: http://en.wikipedia.org/wiki/Piezoelectricity Piezoelectric sensors are attached to the target material. The subsequent deformation caused by the shockwave induced by the beam generates a voltage in the piezo.

9. 9 Jennifer L. Loos jloos@slac.stanford.edu 9 SULI Presentation August 13, 2009 Miniature Multilayer Piezo Stack Actuators * Sub-Millisecond Response * Sub-Nanometer Resolution * Vacuum Compatible to 109 hPa http://www.physikinstrumente.com/en/products/primages.php?sortnr=100800&picview=1#gallery

10. 10 Jennifer L. Loos jloos@slac.stanford.edu 10 SULI Presentation August 13, 2009 RTDs (Resistant Temperature Devices) We also decided to attach RTDs to the target for comparison and calibration purposes. These were modified to a four-wire design for a more accurate measurement of resistance. Selected based on: - Ceramic and platinum materials, both acceptable in vacuum - dimensions (to be attached to a small target)

11. 11 Jennifer L. Loos jloos@slac.stanford.edu 11 SULI Presentation August 13, 2009 What material should be used for the target? Need very hard target material as it will be hit by the x-ray beam Material must also have appropriate acoustic properties B4C would be safer, but acoustic properties needed to be determined Material Boron Carbide (B 4 C) Beryllium Mohs Hardness Scale 9.35.5 Acoustic Properties ? (had to be tested) Clear ‘ringing’ signal (not ‘thud’) Atomic Weight ~11.05099.01218 SafetyNon-toxicToxic

12. 12 Jennifer L. Loos jloos@slac.stanford.edu 12 SULI Presentation August 13, 2009 Signal Seen in Initial Test of Piezos and B4C Using a Frequency Generator One piezo is driven by a frequency, the response from the second piezo is measured.

13. 13 Jennifer L. Loos jloos@slac.stanford.edu 13 SULI Presentation August 13, 2009 Second Laser Test

14. 14 Jennifer L. Loos jloos@slac.stanford.edu 14 SULI Presentation August 13, 2009 Target Target : cubic centimeter (1.25 x 1 x.8 cm) B 4 C

15. 15 Jennifer L. Loos jloos@slac.stanford.edu 15 SULI Presentation August 13, 2009 Translator and Feedthrough Assembly

16. 16 Jennifer L. Loos jloos@slac.stanford.edu 16 SULI Presentation August 13, 2009

17. 17 Jennifer L. Loos jloos@slac.stanford.edu 17 SULI Presentation August 13, 2009 Design must also incorporate existing YAG screen All of the pieces put together!

18. 18 Jennifer L. Loos jloos@slac.stanford.edu 18 SULI Presentation August 13, 2009

19. 19 Jennifer L. Loos jloos@slac.stanford.edu 19 SULI Presentation August 13, 2009 Assembly

20. 20 Jennifer L. Loos jloos@slac.stanford.edu 20 SULI Presentation August 13, 2009 Third Laser Test

21. 21 Jennifer L. Loos jloos@slac.stanford.edu 21 SULI Presentation August 13, 2009 Acknowledgments Many thanks go to The Department of Energy Office of Science and the SULI program for providing this rewarding and very educational opportunity. Special thanks also go to my mentor Joe Frisch, Tonee Smith, Mark Petree, Phil Cutino, Dave Shelley and the machinists in Light Fabrication who lent their extensive expertise to this effort. Thanks also to fellow SULI student Greg Bentsen.

22. 22 Jennifer L. Loos jloos@slac.stanford.edu 22 SULI Presentation August 13, 2009