1. XII-th Collaboration MeetingJan 18, 2008@Cosener's House1 LOI PROGRESS: JANUARY 2008 AT THE HALL 2 Yoshiro Irie, KEK for the LOI/SH collaboration

2. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 2 FLOWER OF THE DAY winter cherry!

3. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 3 PAST 1 at the MICE Hall in August 25, 2005 RF envelopes and 50Hz gate pulse. From top trace, ch.1 driver stage voltage (120×), ch.2 cavity gap voltage (1,666×), ch.3 cavity input current (20A/V) and ch.4 50Hz gate pulse. 15.1V peak-to-peak at ch.2 corresponds to 12.6KV peak per gap. MICE HALL in December, 2004.

4. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 4 PAST 2 at the Hall2 in June, 2007 ~10kVpeak per gap obtained at 2.17MHz without bias current (just recovered to the status in December, 2004) gap voltage (X1,666)

5. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 5 PRESENT at the Hall2 in January, 2008 tested in a frequency swept mode at 50Hz ~11kVpeak per gap obtained near at the B-minimum operation limits: fault of triode grid supply and over-current of triode anode supply gap input current (0.1volt/amp) grid voltage (X 121) grid input current (0.1volt/amp) gap voltage (X 1,666)

6. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 6 REQUIREMENTS PRIOR TO THE EXPERIMENTS need a softer step-start, otherwise blow fuses at the H.P.R.F switchboard, increase power capacity of a variac for the screen psu, reinforce the by-pass capacitor at the input of grid bias supply in the LOI, newly install the grid input current monitor, increase the Buck Regulator output power threshold. : All done successfully

7. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 7 CAPACITOR BLOW June 7, 2007 capacitor blown at the DC output terminal higher power capacitor fixed at the DC output terminal replaced, Jan. 2008 reinforced to 28nF, Jan. 2008

8. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 8 FORWARD1: Investigations waveform distortions? why the cavity impedance looks so low? cavity impedance looks ~400ohms at initial stage of acceleration cycle FT analysis in 2005 also showed 384ohms our design assumption > 2kohms (R Bendall, ISIS/DHRF/P2/97) operation with feedback loops; AVC, phasing to fundamental cavity, cavity tuning, water supply at the SP6 enough for the LOI HPD? required: 396 liter /min. breakdown, 1643Triode: 130 liter /min. 4648Tetrode: 236 liter /min. Feedback shunt resistor: 30 liter /min.

9. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 9 WAVEFORM DISTORTIONS 1. results in August, 2005 Waveform distortions at 2.76, 4.04, 5.01 and 6.20MHz. (August, 2005) From top trace, ch.1 driver stage voltage (x 120), ch.2 cavity gap voltage (x 1,666) ch.3 cavity input current (20A/V) and ch.4 50Hz gate pulse. 6.20 MHz5.01 MHz 4.04 MHz2.76 MHz

10. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 10 WAVEFORM DISTORTIONS -cont’d 2. this experiments similar results were obtained with the previous ones delay from “T” : 1msec ~2.85MHz delay from “T” : 5msec ~5.2MHz gap input current (0.1volt/amp) grid voltage (X 121) grid input current (0.1volt/amp) gap voltage (X 1,666)

11. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 11 OTHER WAVEFORMS ch 1. BR output voltage @J2 (10kV/div) ch 2. BR output current @J3 (12.5Amps/div) ch 3. driver anode current (inverted, 20Amps/div)

12. XII-th Collaboration Meeting Jan 18, 2008@Cosener's House 12 FORWARD2: to-do-list build a new breakout box at the SP6, lay cables between breakout boxes in Hall2 and SP6, etc.. END