# Presentation: 407874

## Coherent Tune MeasurementDesign Review

**Michelle Wilinski**
**March 26, 2003**

## Outline

- Action Items from July 2002 Review
- Overview
- High Voltage Pulser
- Tune DAQ
- Process Variables
- Acceptance Criteria
- Summary

- Diagnostics Review  - March 26 & 27, 2003

## July Review Action Items – Committee Findings

- Tune can be measured using turn-by-turn mode included in BPM system; driving beam with BIG kicker can augment signal
- Agree, system designed using such
- Numerous measurement methods were described, but not implementation details
- To follow

- Diagnostics Review  - March 26 & 27, 2003

## Coherent Tune Overview

- Hardware used:  pulser, kicker, BPM & associated DAQ/processing electronics
- Initial processing executed in BPM PCI card
- Tune calculations performed in a LabVIEW program
- Measured one or more times during accumulation cycle for 1-10 turns
- AP required measurement accuracy = +/- 0.001
- AP required measurement resolution = +/- 0.0005
- Measurement requires averaging

- Diagnostics Review  - March 26 & 27, 2003

## Coherent Tune Block Diagram

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Hardware:  PC with pertinent cards in instrumentation room, pulser in HV room, kicker and BPM in tunnel

## Coherent Tune & BIG Kicker

- Voltage = +/- 7KV     Aperture = 21cm
- Length = 4.5m (3 striplines of 1.5m each)
-  = 0.6mrad         = 15m
- Amplitude (p-p) = 2cm
- p/p = .01
- Chromatic Tune spread =  p/p = .08
- Decoherence time about 12 turns

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Kicker info, “borrowed” from July 2002 presentation

## Pulser Block Diagram

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Switch configuration changed to half bridge method 3-6-03

## High Voltage Pulser Specifications

- Pulser will need to drive ~250ft (76m) of 7/8 Heliax to kicker with length (including interconnects) of 4.7m to 50 load
- HV power supplies: 			+7kV, -7kV
- Switch voltage rating:			14kV
- Output polarity changed on turn-by-turn basis
- Trigger level:			30V
- Rise & Fall Times:			30ns
- Pulse length:				190ns
- Switch between output modes, preferably at 60Hz:
- 1MHz burst of 1-10 pulses repeated at 60Hz (Tune)
- 1MHz burst of 60-100 pulses repeated at 60Hz (BIG)
- Switch between kicking on horizontal or vertical planes
- Average 1kW delivered to load when kicking vertical, dominant mode
- Average 50W delivered to load when kicking horizontal
- No short circuit/collision protection - effects of short

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Change to 1 pulse length, benefit to using 1 pulse length at 190ns -> tune for leading edge of beam may be different from trailing edge, adjustable between 170-230ns
Have gap length ~250ns = 190 kick pulse + 30 rise + 30 fall
Short/open effects:  short in line at appropriate length away would invert signal & put 14kV across switch
Collision effects:  both switches in pair close, obtain virtual ground

## Short/Open/Collision Effect on Pulser

-   An short or open will cause a reflection of pulse, 14kV across closed switch
-   A switch pair collision will cause virtual ground between pair

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Switch configuration changed to half bridge method 3-6-03, cable is 7/8 Heliax to kicker
Short reflection will be inverted; worst case depends on cable length back to pulser being such that the incident pulse & reflected pulse will overlap.

## HV Pulser Status

- Pulser unit will be located in High Voltage Room
- Option 1 -Purchase pulser as one integrated unit from vendor
- Diversified Technologies, Inc. (MA)
- Cost:	$250k (not including integration/testing at BNL/SNS)
- 8 switches @ $20k/ea. = $160k	•  2 power supplies = $10k
- Controls/integration/test = $40k	•  NRE (20ns RT/FT) = $40k
- Lead time 6-8 months
- unit would fill one complete rack
- Directed Energy, Inc. (CO)
- No existing product, will not custom design for small procurement
- Option 2 - Purchase items separately and construct at BNL
- Switch vendors
- Power supply vendors
- Lambda/EMI: +10kV & -10kV supplies, $6,680/ea. ($13,360 for two), 8-10 week lead time
- Universal Voltronics: waiting for response
- Introduces manpower & labor costs for design & construction

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
DTI has currently a switch module with 30ns RT/FT – is 20ns RT/FT worth the cost, tradeoffs? AP people performing simulations for such

## DTI Switch Module

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Picture of switch module from Diversified technologies.

## Tune DAQ:  BPM PCI Card

**EL & RTDL**
**Receivers**

- Event Link

- RTDL

- PCI BUS

- T 0 TRIGGER

**SSRAM**

**SIGNAL DIGITIZERS**

**ALTERA**
**FPGA**

- ADC Clock.

**Amplifiers**** **
**and Signal**
**Conditioning**

- Control I/O

**PUE**

- Power Supply

*Tune DAQ:  BPM PCI Card*

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
PCI diagram, presentation by C. Dawson, March 2003

## Tune DAQ & Processing

- Tune will be using the BPM PCI interface card for data acquisition
- Tune system control done by existing Altera FPGA on card
- Pulser trigger – additional output from FPGA
- Since Tune & BIG hardware and processing applications will be in different PCs, control logic (in hardware and/or software) to prevent both systems from triggering the pulser at once is necessary
- After initial processing on PCI card, LabVIEW will carry out remaining processing
- Utilize LabVIEW template written by W. Blokland, bpm.dll, program written for BNL’s Booster Tune Meter  build on existing applications for ease of future modifications

- Diagnostics Review  - March 26 & 27, 2003

## Booster Tune Meter  (BTM) LabVIEW front panel

-   Contains programmatic controls, graphs for displaying raw data & FFT tune results on Main front panel tab
-   Other front panel tabs (not shown) contain scope info, returned parameters from processing algorithm, error messages, help files

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Overall view of front panel – next two slides show sections closer up.  Other front panel tabs (scope status & display, diagnostics, CIN-History Display, Error Listings, Help) not shown explicitly
CIN = code interface node, LabVIEW specific term, used to attach C code to LabVIEW

## BTM Controls

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Front panel controls portion of Booster Tune Meter LabVIEW program:  Server controls – controls to communicate with server, IP address & port, TCP timeout, delay for acquisition -> not necessary for SNS; Algorithm controls – Control parameters for attached C code for algorithm processing (code written by K. Brown, BNL Physicist); SpreadSheet controls – set of parameters which talk to the Controls SpreadSheet application for trigger timing and active user (also uses attached C code written years ago by N. Williams, BNL Controls); remaining controls self explanatory for programmatic control

## BTM Controls/Display

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Left column horizontal data; right column vertical data – top graphs display (sum/difference) data array, middle graphs display FFT of (sum/diff) data array, bottom graphs display a zoomed in version of the FFT, user can control the zoom factor by entering zoom mode (pressing zoom buttons); data taken from polarized proton machine setup run in late February
User has ability to turn kicker on/off, set voltage level and kick length (top of image)
Next to FFT graphs are indication of peak location & width of the FFT

## Process Variables – System Inputs

- Kick polarity
- Determines output polarity of kick (+/- or -/+)
- Plane to kick
- Determines plane to kick (horizontal or vertical)
- Kick trigger
- When to trigger the pulser for kick(s)
- BPM PCI process type
- Determines processing type on PCI card (baseband or RF processing)
- Other applicable BPM PCI process variables
- Power supply on/off
- Remote control for the power supply
- RTDL
- Event Link

- Diagnostics Review  - March 26 & 27, 2003

## Process Variables - System Outputs

- Kick mode
- Determines mode of pulser operation (Tune or BIG)
- Tune measurement
- Calculated result from LabVIEW
- Tune spread
- Calculated result from LabVIEW
- Power supply remote/local
- Readback to determine mode
- Power supply on/off
- Readback to determine if supply is on/off
- Capacitor bank voltage
- Readback to assure power supply is charged as expected

- Diagnostics Review  - March 26 & 27, 2003

## Acceptance Criteria

- Meets applicable BPM acceptance criteria
- Meets AP specifications
- Test on resonator
- Accuracy +/- 0.001
- Resolution +/- 0.0005
- Pulser meets requirements
- Output +/- 7kV
- Polarity changed turn-by-turn
- Select plane to kick
- 1MHz burst of 1-10 pulses
- Vertical System Integration to EPICS screen demonstrated

- Diagnostics Review  - March 26 & 27, 2003

## Cable Plan

- Cabling from BPM to be as specified for BPM system
- 50 ohm phase-matched and stabilized heliax (1/4 or 3/8 inch)
- Terminated in  bulkhead N connectors with N to SMA adapters. Short, flexible, 50 ohm coaxial cables terminated in SMA connectors will be used to make the connections from the Heliax to the electronics and PUE’s.
- Cabling from pulser direct to kicker will be 7/8 heliax terminated in L5PN series high-power connectors. DTI recommends 75 ohm cable (standard Andrew item)
-  kicker design is being revisited to look at matching this impedance.

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Extra miscellaneous oddities

## Summary

- One pulser unit & kicker to be shared among Coherent Tune and Beam in Gap systems
- Pulser option to be selected - confident of vendor capability but hesitant because of cost
- Using BPM and PCI card for data acquisition; only additional hardware is pulser trigger.
- Put experience with Tune systems at BNL to work

- Diagnostics Review  - March 26 & 27, 2003

## ...extras...

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Extra miscellaneous oddities

## Schedule - Tune

*Schedule - Tune*

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Schedule generated for Feb. ORNL visit, vertical line indicates Feb. point

## DEI +/-6kV pulser

| Parameter | DEI | Spec |
| --- | --- | --- |
| Voltage | +/-6kV | +/-7kV |
| Rise/Fall Time | <60ns (54 ns typical) | 30ns |
| Pulse width | <200ns to DC
Gate controlled | 220ns |
| Input gate trigger | 5V | 30V |

- Requires TTL gate input, HV DC power supplies
- Output pulse width & frequency controlled by gate trigger; voltage controlled by power supply amplitude
- 8 units - $11,475ea. ($91,800); 10 units - $10,950 ($109,500)

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Spec comparison with the DEI (Directed Energy Inc., CO) pulser – DEI will not custom design for small quantity procurement

## Lambda/ALE HV PS – 402 Series

- AC Input:			208VAC
- Avg. Charging Rate:		4000J/s at rated voltage output
- Peak Charging Rate:		5000J/s at rated voltage output
- Voltage:			+10kV, -10kV (2 units)
- Pulse-to-pulse repeatability:	+/-2% to 1kHz
- Protection against open circuit, short circuit, overload, arcs
- 19” rack mountable
- Similar to supply used for ARTUS (RHIC tune meter) – uses +5kV version

- Diagnostics Review  - March 26 & 27, 2003

**Notes:**
Local rep for Lambda – Gregg Toback, Tera Technologies