Status of SPARC e-meter & activities of the Roma2 Group

1. Status of SPARC e-meter&activities of the Roma2 Group INFN-Roma2 L. Catani, E.Chiadroni, A.Cianchi, E. Gabrielli, S.Tazzari, M. Sabene(DAQ), G. Salina (DAQ), A. Salamon (DAQ) INFN-LNF (Emittance-meter) M.Castellano, M.Boscolo, A.Clozza, G.Di Pirro, M.Ferrario, V.Fusco, D.Filippetto, V.Lollo, R.Sorchetti, C.Ronsivalle (ENEA), C.Vaccarezza, Federico Anelli, Sandro Fioravanti L.Catani for the e-meter Group

2. Topics • Progress with e-meter construction • Upgrade of mechanical design • Tests & calibrations of components (YAG screens, long.movers, tilts) • Pepper-Pot (1st & 2nd series) • Collaboration with DESY-Zeuthen • LoU on the measurements with e-meter • Installation at PITZ • Measurements@PITZ: schedule • Activities@INFN-Roma2 • Bunch length diagnostic, eLogbook, DAQ, Controls L.Catani for the e-meter Group

3. SPARC e-meter timeplan L.Catani for the e-meter Group

4. E-meter completed L.Catani for the e-meter Group

5. new “PITZ-compatible” design (V.Lollo) L.Catani for the e-meter Group

6. Tools for installation on PITZ girder(V.Lollo) L.Catani for the e-meter Group

7. Analysis of the pepper-pot slit width (A.Cianchi) • Optical microscopy with CCD • Calibrated with a grid of 5 µm step • Systematic error on calibration ∼1% L.Catani for the e-meter Group

8. Fenditura 100 mm (100X) 200 X 89,53 95,45 89,58 93,46 92,16 100X 91,7 L.Catani for the e-meter Group

9. 3 m Slit target #1 100 m L.Catani for the e-meter Group

10. Slit target #1 50 m 200 X 49,30 49,47 49,87 49,43 100X 49,4 L.Catani for the e-meter Group

11. 125 m L.Catani for the e-meter Group

12. 50X 1 L.Catani for the e-meter Group

13. 50 X 7 L.Catani for the e-meter Group

14. 200 X ---------------------------------- 7f 53,7 53,2 52,6 6f 53,8 5f 56 4f 48 47,8 3f 57,1 57,8 2f 45,7 46,4 46,7 1f 56,4 55,3 49,5 100 X ---------------------------------- 7f 53 6f 56 2f 46 50X ---------------------------------- 1f 53 2f 42 5f 51 7f 53 Results ofmeasurements • # 3 seems to be out of standard • For #5 and #6 is difficult to have good depth of field L.Catani for the e-meter Group

15. New pepper-pot 10 X ---------------------------------- 100µ 96 6f 53 -- 51 -- 52 5f 51 4f 57 -- 55 -- 56 3f 48 -- 48 2f 54 50 um 100 um L.Catani for the e-meter Group

16. Control & Analysis software L.Catani for the e-meter Group

17. YAG screens tests(D.Filippetto, M.Castellano, A.Cianchi) Tasks: • Test the digital camera and imaging system designed for the e-meter (digital camera + high quality objective for 1:1 magnification) • Evaluation of resolution and linearity of YAG screens for different charge densities (compared to ceramic Cr-Oxide screen) L.Catani for the e-meter Group

18. Measurement Set Up YAG screen Macro lens (1:1) Basler camera Firewire interface L.Catani for the e-meter Group

19. Design values • The highest charge density before saturation depends on the quantity of dopant (Ce); for our screens this value is 0.18% that defines a limit of • At SPARC e-meter beam size will show the following limits • @145cm from cathode • @85 cm from cathode • Assuming a Gaussian transverse shape and a charge of 1nC we can estimate the maximum charge density on the YAG screen as Saturation value shouldn’t be reached with SPARC beam L.Catani for the e-meter Group

20. MEASUREMENTS CROMOX vs. YAG (identical beam conditions) (false colors palette) YAG screen shows two relevant advantages with respect to CromOx: higher sensititvity and much better resolution; the beam image produced by the YAG screen shows details (a well defined beam core, a structured beam tail) not visible with the CromOx L.Catani for the e-meter Group

21. ANALYSIS CROMOX (AU) YAG (AU) Comparison of “same beam” (averaged) images from the two screens: intensity levels of the bitmap are compared and a saturation effect is evidenced in the CromOx values L.Catani for the e-meter Group

22. Calibration of rotation stages of the pepper-pot chamber (D.Filippetto, A.Cianchi) The cross housing the horizontal and vertical pepper-pot has two rotation stages to adjust the angle of the slits with respect to the beam direction. Each stage is moved by a stepper motor having 200 steps per turn. µ-step movement is also possible (256 µ-steps per step). Taking into account the system of gears the resolution of the system is Rotation stage for the horizontal slits pepper-pot L.Catani for the e-meter Group

23. Setup A laser beam is reflected toward a CCD camera by a mirror mounted on the chamber top flange. The camera pixel size is 10 µm (objective is not installed). The chamber is rotated moving the motor of a well known number of steps and the laser beam spot on the CCD moves a correspondent number of pixels. A software automatically filters the image and calculate the center of mass of the beam spot. The rotation angle can be easily calculated by knowing the length of the optical path L.Catani for the e-meter Group

24. Results (rotation angle per single µ-step) Results are close to the expected values and definitely compatible with the needed resolution of the rotational movement. Improvement is also possible by fine tuning of the assembly of mechanical components L.Catani for the e-meter Group

25. Alignment procedure (F.Sgamma, V.Lollo) Alignment reference Alignment tools for the movable parts PITZ girder L.Catani for the e-meter Group

26. Alignment of the e-meter @LNF L.Catani for the e-meter Group

27. Letter of Understandingwith DESY–Zeuthen L.Catani for the e-meter Group

28. SPARC e-meter@PITZ: measurement program(L.Catani, A.Cianchi, E.Chiadroni, D.Filippetto, C.Vicario) June: shipment & installation July: commissioning&training August: measurements L.Catani for the e-meter Group

29. SPARC e–meter website L.Catani for the e-meter Group

30. Preliminary Bunch Length Measurement (E.Chiadroni) 0.52 ps < rms bunch length < 1.2 ps (@ 12 deg) (almost on crest) Bunches per train: 1 Charge: 0.3 nC per bunch Gun phase: 14.00 deg Energy: 380 MeV ACC1 phase: 128.61 deg (on crest) ACC1 gradient:13.60 MV/m ACC23 phase: variableACC23 gradient: 18.00 MV/m L.Catani for the e-meter Group

31. Experimental Setup In principle, 60 mm < sb < 6 mm, where the lower limit is given by twice the spacing between the wires and by the flange window used (z-cut crystalline quartz) and the upper limit by the detector window diameter. However, detector acceptance, grids apertures, mirrors and window provide a further cut–off, which means 60 mm < sb < 2 mm. Mathematica Code by B. Schmidt (DESY) L.Catani for the e-meter Group

32. Comments The interferometer is placed in a metal blackened box to be shielded from light and e.m. noise and operates in air The st values in the right plot (first slide) are given by fitting the interferograms with either a Gaussian function (black curve) or a “3-Gaussian” one as follows The “3-Gaussian” fitting function has been obtained by J.B. Rosenzweig et al. by introducing an analytical filter function of the form g(w)=1-exp(-x2w2) and assuming the autocorrelation of the signal in the frequency domain as the product of the spectral beam density r(w) (assumed to be Gaussian) and g(w): rf(w)=r(w) g(w) and the spectrum of the measured signal is s(w)=|rf(w)|2. x gives the interferometer cut-off parameter which corresponds to l = 1.94 mm L.Catani for the e-meter Group

33. Newe-Logbook(E.Gabrielli) L.Catani for the e-meter Group

34. DAQ PCI boards (M.Sabene, A.Salamon)(first prototype under fabrication) L.Catani for the e-meter Group

35. A development with possible applications in the SPARC Control System:communication based on standard data format (XML)(E. Gabrielli, L.Catani) L.Catani for the e-meter Group

36. XML limitations for large binary arrays (images) L.Catani for the e-meter Group

37. Advantage of an XML pre-processor L.Catani for the e-meter Group

38. ..then use XML-RPC example of an XML-RPC request <?xml version="1.0"?> <?xml version="1.0"?> <methodCall> <methodName> get_timestamp </methodName> <params> no.params </params> </methodCall> example of a response to an XML-RPC request <?xml version="1.0"?> <methodResponse> <params ><U32> <Name>Timestamp</Name> <Val>3201067896</Val> </U32> </params> </methodResponse> L.Catani for the e-meter Group

39. ..a copy (some Korean colleagues) L.Catani for the e-meter Group