1. Christoph Gabor, ASTeC HIPPI—Meeting (WP 5) 26 th – 28 th September 2007 Non—destructive transverse emittance measurement device The Front End Test Stand Collaboration C. Gabor, J. Pozimski, A. Letchford

2. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Outline Introduction FETS, Photo detachment & basic principle of beam diagnostic Theoretical investigations Proof of principle experiment Demonstration experiment at a small H- beam line in Frankfurt Further Hardware Summary & Outlook

3. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Layout of the Front End Test Stand FETS 3MeV beam energy, ~ 60mA H - 50Hz, <2ms (10% duty cycle) at David Lee and Juergen Pozimski, Imperial College

4. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Photo Detachment H — beam diagnostic non destructive (i.e. no mechanical parts inside the ion beam) => minimizing the influence on the H- beam (on line) highly suitable for high power applications like FETS different applications possible: profile(s), emittance ~ electrons, neutrals, laser power attentuation ~ more information about beam are possible, also with good resolution ~ separating neutrals and H- can cause less flexibility because of dipole ~ higher costs compared with a traditional emittance scanner

5. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Non-destructive, transverse H- emittance measurement Comparission with a slit—slit emittance instrument: 1 st slit is replaced by a laser 2 nd slit is replaced by a scintillator with CCD camera  more information (than 2dim) about phase space Only a small portion of H- will be neutralized, i.e. max. portion of laser interaction

6. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Different emittance measurement principles Envellope of the ion beam Cross section of the ion beam Slit—slit Principle : only 2dim phase space  =  2dim (y,y') Point—point Principle : full 4dim information about phase space

7. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Photo detachment simulations about its transfer function Left, beam profile I(y') integrated of the emittance pattern and integration of drifted, (100mm) neutralized particles (dots). Right, the "neutralized particles" at +/-10mm and the drifted particles, enclosed by the neutralized patterns, are shown. beam profile phase spaceneutralized particles, drifted particles

8. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Comparision of simulation & measurement prf101.spe prf139.spe X Y’Y’ y=-3,8mm y=+8,4mm 2dim yy‘ emittance simulation close to the experiment experimental results at different laser positions simulation of photo neutralized ions of the xy distribution (drift length 500mm

9. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Further, current development work vacuum vessel space for piezo driven stages arc lenght: 500 mm deflection angle: 60 deg B—field: 0.522 T homogeneity (waist) along the H- ion beam (collimation/ focusing) different angles within scanning region Limiting spatial resolution

10. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Summary -- Introduction about Photo detachment ion beam diagnostics Motivation; different principles of diagnostic using photo detachment; Comparison with other emittance measurement methods -- Theoretical aspects investigations about transfer function of "slit—point" emittance -- Proof of principle experiment in Frankfurt, Germany Outlook and recent work Further hardware: diagnostic dipole & laser equipment testing laser beam line/ movable mirrors particle detector (beam test of scintillators like P43, 45 improving theoretical understanding Longitudinal emittance measurement

11. Christoph Gabor, UKNF—Meeting, 3 rd October 2007

12. Spare slides

13. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Piezoelectric motors: status Motion controller Rotary stage Amplifiers and power supplies Linear stage Encoders

14. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Motivation for non-destructive diagnostics 665keV H - 1...3% dc 30....40mA 500 W/cm 2 (by Alan Letchford) Water cooled end plate of a Fast Faraday Cup (unfocused ion beam) Measurements at the current ISIS RFQ Scintillator image of H- ion beam after the ion source => beam not cylindrically symmetric mainly caused the slit extraction of the ion source xy intensity distribution of H-, 35keV 45mA, (Ion source test stand)

15. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Some data about Front End Test Stand FETS

16. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Integration of a photo neutralized & drifted H- distribution CCD image (raw data) + P43 with Alu y x Relationship between y,  y and y' yy

17. Christoph Gabor, UKNF—Meeting, 3 rd October 2007 Laser characterisation, beam guiding Laser lab at Imperial college Power meter Attenuation CCD camera Switching mirror