Status of SPARC emeter activities of the Roma

Status of SPARC e-meter & activities of the Roma 2 Group INFN-Roma 2 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

Topics – Progress with e-meter construction • Upgrade of mechanical design • Tests & calibrations of components (YAG screens, long. movers, tilts) • Pepper-Pot (1 st & 2 nd series) – Collaboration with DESY-Zeuthen • Lo. U on the measurements with e-meter • Installation at PITZ • Measurements@PITZ: schedule – Activities@INFN-Roma 2 • Bunch length diagnostic, e. Logbook, DAQ, Controls SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 2

SPARC emeter timeplan SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 3

E-meter completed SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 4

new “PITZ-compatible” design (V. Lollo) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 5

Tools for installation on PITZ girder (V. Lollo) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 6

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% SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 7

Fenditura 100 mm (100 X) 200 X SPARC Rev. Comm. Meeting 14 June 2005 89, 53 95, 45 89, 58 93, 46 92, 16 100 X L. Catani for the e-meter Group 8 91, 7

Slit target #1 100 m 3 m SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 9

Slit target #1 50 m 200 X SPARC Rev. Comm. Meeting 14 June 2005 49, 30 49, 47 49, 87 49, 43 100 X L. Catani for the e-meter Group 10 49, 4

125 m SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 11

50 X 1 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 12

50 X 7 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 13

Results of measurements 200 X • # 3 seems to be out of standard • For #5 and #6 is difficult to have good depth of field 100 X 50 X SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 14 -----------------7 f 53, 7 53, 2 52, 6 6 f 53, 8 5 f 56 4 f 48 47, 8 3 f 57, 1 57, 8 2 f 45, 7 46, 4 46, 7 1 f 56, 4 55, 3 49, 5 -----------------7 f 53 6 f 56 2 f 46 -----------------1 f 53 2 f 42 5 f 51 7 f 53

New pepper-pot 10 X ----------------50 um 100 um SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 15 100µ 96 6 f --5 f 4 f --3 f -2 f 53 51 52 51 57 55 56 48 48 54

Control & Analysis software SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 16

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) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 17

Measurement Set Up YAG screen Macro lens (1: 1) Basler camera Firewire interface SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 18

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 – @145 cm from cathode – @85 cm from cathode • Assuming a Gaussian transverse shape and a charge of 1 n. C we can estimate the maximum charge density on the YAG screen as Saturation value shouldn’t be reached with SPARC beam SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 19

MEASUREMENTS CROMOX vs. (identical beam conditions) YAG (false colors palette) YAG screen shows two relevant advantages with respect to Crom. Ox: 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 Crom. Ox SPARC Rev. Comm. L. Catani for the e-meter Group 20 Meeting 14 June 2005

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 Crom. Ox values SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 21

Calibration of rotation stages of the pepperpot 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 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 22

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 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 23

Results (rotation angle per single µ-step) Direction: Mean Value (µrad) Standard deviation (µrad) Min value (µrad) Max value (µrad) DX: 2. 36 0. 215 2. 12 2. 55 SX: 1. 835 0. 28 1. 51 2. 04 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 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 24

Alignment procedure (F. Sgamma, V. Lollo) Alignment reference Alignment tools for the movable parts PITZ girder SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 25

Alignment of the e-meter @LNF SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 26

Letter of Understanding with DESY– Zeuthen SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 27

SPARC e-meter@PITZ: measurement program (L. Catani, A. Cianchi, E. Chiadroni, D. Filippetto, C. Vicario) June: shipment & installation July: commissioning&trainin g August: measurements SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 28

SPARC e–meter website SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 29

Preliminary Bunch Length Measurement 0. 52 ps < (@ 12 deg) Bunches per train: Gun phase: ACC 1 phase: ACC 23 phase: SPARC Rev. Comm. Meeting 14 June 2005 (E. Chiadroni) rms bunch length < 1. 2 ps (almost on crest) 1 14. 00 deg 128. 61 deg (on crest) variable Charge: Energy: ACC 1 gradient: ACC 23 gradient: L. Catani for the e-meter Group 30 0. 3 n. C per bunch 380 Me. V 13. 60 MV/m 18. 00 MV/m

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) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 31

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(-x 2 w 2) 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 SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 32

New e-Logbook (E. Gabrielli) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 33

DAQ PCI boards (M. Sabene, A. Salamon) (first prototype under fabrication) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 34

A development with possible applications in the SPARC Control System: communication based on standard data format (XML) (E. Gabrielli, L. Catani) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 35

XML limitations for large binary arrays (images) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 36

Advantage of an XML pre-processor SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 37

. . then use XML-RPC example of an XML-RPC request <? xml version="1. 0"? > <method. Call> <method. Name> get_timestamp </method. Name> <params> no. params </params> </method. Call> SPARC Rev. Comm. Meeting 14 June 2005 example of a response to an XML-RPC request <? xml version="1. 0"? > <method. Response> <params ><U 32> <Name>Timestamp</Name> <Val>3201067896</Val> </U 32> </params> </method. Response> L. Catani for the e-meter Group 38

. . a copy (some Korean colleagues) SPARC Rev. Comm. Meeting 14 June 2005 L. Catani for the e-meter Group 39