BCM Update Kesselman BNL Review 3 26 03

BCM Update Kesselman BNL Review 3 -26 -03 1

OUTLINE • Findings/Response to FDR held for HEBT, Ring, RTBT Systems at BNL 722 -02 • Specs/Preliminaries • Status • Over-view of BCM electronics BNL Review 3 -26 -03 2

FDR (7 -22 -02) Committee Comments and Responses - 1 – BCM should be part of the Machine Protection System Response: This is not in the base-line. It is a requirement for machine protection at low energy and there will be a discussion session on Thursday afternoon. – The Beam Current Monitoring system appears to be in good shape. Problems with cables and connectors. Response: Installation procedure implemented by ORNL. – The PCI data acquisition card (also used for the BPMs) is not yet finalized. Response: Done – The calibrate module is not yet finalized. Response: Bergoz has provided transformer failure mechanisms. A fused driver is under consideration. More to BNL Review 3 -26 -03 follow. 3

· FDR (7 -22 -02) Committee Comments and Responses - 2 – A bandwidth-limiting filter should be placed in front of the BCM amplifiers to avoid problems caused by out-ofband high frequency signals. Response: An input capacitor has been added to limit system bandwidth to 100 MHz. – There is apparently evidence of a 600 to 700 MHz resonance in the BCM shroud. Consider placing distributed series RC elements across the ceramic gap to shunt high frequency beam image currents. Response: Noted. Measurements indicate minor peak and not a concern. New design reduces volume. BNL Review 3 -26 -03 4

FDR (7 -22 -02) Committee Comments and Responses - 3 – The shroud and its connections to the beam tube should be designed and tested to handle SNS 50 amp current. Response: New design uses no “fingers” to carry current and this is no longer a concern (design to be shown later). –The FPGA should be programmed to not allow nonsense settings. Response: Agree and implemented BNL Review 3 -26 -03 5

FDR (7 -22 -02) Committee Comments and Responses - 4 – Software should verify the integrity and sensibility of measurements, e. g. check for saturation that may result from incorrect gain settings. Response: We will incorporate such software. Inclusion of the Alterra FPGA will permit appropriate logic to be added to assure correct gain settings. – User requirements for beam current monitoring information seem to still be lacking. Response: Being dealt with at applications level BNL Review 3 -26 -03 6

Major Milestones • DTL – 1 st week in May ’ 03 – Present perception is a 6 week slip • Ring Hardware – Late Jan ’ 04 – On schedule BNL Review 3 -26 -03 7

Schedule

SNS DESIGN PARAMETERS • • Energy……………. . 1 Ge. V Intensity……. . …………………. 1. 5 x 1014 protons Repetition Rate…. ……………. . 60 Hz Number of Bunches…. . ………. . . 1 Injection duration………………. 1. 0 msec Revolution Period……. … 945 nsec Bunch Length…. ………………. . . 695 nsec Number of turns…………………. 1060 BNL Review 3 -26 -03 9

BCM Requirements From SNS Diagnostics AP Requirements (11/05/02) • MEBT to HEBT 0. 3 - 1000 us, • • 15 to 52 m. A Accuracy < 1% of FSR Resolution 0. 5% of FSR Detail within mini-pulse- available on demand • Ring to RTBT 5 e 10 to 2 e 14 Protons • • 0. 015 A to 100 A Accuracy < 1% of FSR Resolution 0. 5% of FSR Turn-by-turn data- available on demand • Interpretation of requirements BNL Review 3 -26 -03 10

Beam Current Monitor Distribution BNL Review 3 -26 -03 11

System Electronics Configuration DFE XFMR A F E Memory or FIFOs DAC’s & ADC’s 40 MHz/68 MHz LO GAIN PCI DAQ TIMING MODULE Event Link RTDL 16 MHz Reference CLK CONTROL CAL PCI BUSS CONTROL SYSTEM BNL Lab. VIEW Review 3 -26 -03 RACK MOUNT PC 12

System Status • • • A Prototype system has been delivered to LBNL and then upgraded (rev C) and delivered to ORNL. This system failed during commissioning at ORNL (due to unexplained over-voltage) and was repaired. It is presently operating at ORNL. Three (3) additional rev C - BCM systems are in process for delivery in April to support Linac commissioning. We have two LANL PCI cards and are building some more. To replace two parts that have been made obsolete by the manufacture, requires another art-work revision. Our plan is to leave the connectors at board end but assure they stay within the PCI board spec and incorporate minimal artwork changes (present design works). HEBT BCM design is complete. Final drawings are in preparation. Ring, and RTBT BCM design is underway. Calibrator design for the Ring and RTBT is in progress. 13

Elog 1 -29 -03 ORNL MEBT Commissioning Source Delay Mode BNL Review 3 -26 -03 14

HEBT, Ring, RTBT Current Transformers BNL Review 3 -26 -03 15

HEBT BCM ASSEMBLY BNL Review 3 -26 -03 16

COMPONENTS INSIDE HEBT BCM ASSEMBLY BNL Review 3 -26 -03 17

PRELIMINARY RING/RTBT BCM DESIGN BNL Review 3 -26 -03 18

250 us MEBT Pulse – During Berkeley Commisssioning BNL Review 3 -26 -03 19

Process Variables (2 Channels) -1 • Chart Data : – Current chart – comfort display (<256 elements) • Averaged over specified time – Variables » Delay time » Time to display – Particle count chart– (integral of current waveshape) • Particle count, averaged over the entire macro-pulse • Particle count, holding average over each mini-pulse (particles) – array holding raw data for macro-pulse

Process Variables (2 Channels) -2 • Additional PVs – Sampling Frequency – Gain setting – tied to data points – Initialize Hardware Control –True/False(auto reset) – – PCI Card number Delay time from trigger Number of points to store FIFO Selection – Update graphs control ON/OFF – Calibration current value – – – Conversion gain Current calibration value Control to permit calibration analysis ON/OFF Delay time Calculation time – Droop computation – – – – Transformer time constant DC Offset value DC Offset calculation delay time DC Offset calculation time Control to permit droop analysis ON/OFF Droop Calculation - Delay time Droop Calculation - Calculation time

Calibrator Purpose and Requirements • Calibrator Purpose Provide a dynamic, on-line measurement of FCT droop time constant Confirm the gain of the BCM at various settings • MEBT, DTL, CCL, SRF and HEBT (16 Transformers) One range for BCM (0 -100 ma) calibration current from 12 bit DAC (up to 20 ma) • Ring and RTBT (6 Transformers) Will Add 3 BCM ranges. High current driver required (up to 4 amp) 350 ma full scale (35 ma from calibrator) 4. 2 Amps full scale (420 ma from calibrator) 50 Amps full scale (4 Amps from calibrator) High current driver has a rise time of 1. 6 usec, too long for good amplitude meas. Plan on two calibration pulse shapes, pulse for droop, sine wave for gain • Transformer Protection Driver outputs fused to protect from fault currents Limited Current from Driver Power Supplies BNL Review 3 -26 -03 22

BCM Calibrator Block Diagram Shows one of two channels Memory 64 kb/167 Mhz Data/Address 12 Bits To Calibration Winding 0 -10 ma 12 Bit DAC 125 Msps Optical Isolators Timing / Control Logic Timing/ Control BNL Review 3 -26 -03 Differential Driver To calibration Winding (alt. ) 0 -2 Amp 23

Design Features • Basic Design Features A Function Generator using a 12 Bit DAC and a 64 kb memory Two output ports DAC output directly drives lowest current range Current driver drives all other ranges ( 350 ma to 50 Amp) Isolation from local ground provided by opto-isolators and DC/DC converter • Transformer Protection Driver outputs fused to protect from fault currents Limited Current from Driver Power Supplies • Packaging On a multi-layer pcb inside the pc chassis drive bay BNL Review 3 -26 -03 24