HEBT, ring, & RTBT WS System
Download
1 / 22

HEBT, ring, & RTBT WS System Preliminary Design Review BNL, July 23, 2002 by Michael Plum - PowerPoint PPT Presentation


  • 104 Views
  • Uploaded on

HEBT, ring, & RTBT WS System Preliminary Design Review BNL, July 23, 2002 by Michael Plum. and Pete Cameron, CJ Liaw, Ross Meyer, John Power, Bob Shafer. Outline. HEBT wire scanner system Ring wire scanner system RTBT wire scanner system Responsibilities Summary. Quantities & strokes.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' HEBT, ring, & RTBT WS System Preliminary Design Review BNL, July 23, 2002 by Michael Plum' - evangeline-marks


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

HEBT, ring, & RTBT WS System

Preliminary Design Review

BNL, July 23, 2002

by Michael Plum

and Pete Cameron, CJ Liaw, Ross Meyer, John Power, Bob Shafer

M. Plum Slide 1


Outline
Outline

  • HEBT wire scanner system

  • Ring wire scanner system

  • RTBT wire scanner system

  • Responsibilities

  • Summary

M. Plum Slide 2


Quantities strokes
Quantities & strokes

  • All units will use same motion control as linac systems.

    • Phyton linear driver controlled by NI PCI card mounted in a PC.

M. Plum Slide 3


Signal processing wire type
Signal processing & wire type

* wires offset so that no more than one wire at a time is within ±2 rms of beam center.

M. Plum Slide 4


Hebt wire scanners
HEBT wire scanners

  • Beam pipe size is 5” OD

  • Actuators based DTL design, have slightly longer stroke (8” vs. 6”).

    • Custom design fabricated by Huntington.

  • Electronics (actuator control and wire signal) same as for linac.

    • Biased wire, ac-coupled electronics.

    • Linear stepper motor driver.

    • Signal processor.

    • PC.

  • Calculation of wire temperature and signal strength.

    • Max wire temperature limited to about 1225 oC. Any higher and thermionic electron emission becomes significant.

    • Assuming 1000 MeV, 26 mA avg. beam current, 0.10 x 0.15 mm rms beam, this will occur at about 900 us, 1 Hz, and at 110 us, 60 Hz.

M. Plum Slide 5


Huntington 6 stroke wire scanner assembly cover removed
Huntington 6” stroke wire scanner assembly – cover removed

ball lead screw

support housing

signal wire

vacuum connector

LVDT

brake

motor

bellows

fork

micro

switches

carbon wires

collet assembly

M. Plum Slide 6


Block diagram
Block Diagram removed

(Changing to

Phytron linear driver)

Block diagram of the cards in the PC and connections to the electronics chassis, motor driver and wire scanner actuator.

M. Plum Slide 7


Linac signal processor chassis
Linac signal processor chassis removed

Timing TTL monitor signal

Status indicators: power, wire, gain, B.I.T.

WS channel monitor ports

Front panel view of the 1U-high electronics chassis. LEDs indicate power, wire status, gain setting, and B.I.T. state. BNCs allow the user to monitor the analog voltage of each of the three channels, X, Y, Z as well as the timing source.

M. Plum Slide 8


Driver module all ws systems
Driver module – all WS systems removed

  • We plan to switch from the NI chopper driver to the Phytron CLD 20-24 linear driver motor.

M. Plum Slide 9


Beam size in the hebt
Beam size in the HEBT removed

From D. Raparia, 29/Apr/02.

M. Plum Slide 10


Hebt wire scanners cont
HEBT wire scanners (cont.) removed

  • Estimate of accuracy of width measurement.

    • Smallest beam in HEBT is 1.1 mm rms.

    • Assuming

      • A wire positioning accuracy of 0.1 mm (same as expected for linac wire scanner actuators),

      • Absolute signal error of 2% of peak (electrical noise)

      • Relative signal amplitude error of 1% (non linearities)

      • Negligible beam position and beam width jitter

    • We expect to be able to measure the rms beam size with an accuracy of about 7%, including the difference between the rms of a beam and the sigma from a Gaussian fit.

    • Resolution will be about 2%.

M. Plum Slide 11


Hebt wire scanners cont1
HEBT wire scanners (cont.) removed

  • Estimate of signal levels in HEBT.

    • Smallest signal is about 100 times less than signal at center of largest (4.3 mm rms) beam for lowest peak current (10 mA) beam. Computer model predicts 16 nA.

    • Largest signal is at center of smallest (1.0 mm rms) beam for highest peak current (38 mA). Computer model predicts 26 uA.

    • Allow factor of two error >> electronics should ideally be able to measure signals from 8 nA to 52 uA (in several gain stages).

    • Present linac design can measurefrom 7.3 nA to 30 uA in 3 gainstages.

    • Linac electronics may need slightmodification for higher input currents.

M. Plum Slide 12


Ring wire scanner system
Ring wire scanner system removed

  • Beam pipe size is 8” OD.

  • Each actuator will have just one signal wire.

  • Total of two wire scanner actuators (one x, one y) in the ring.

  • Primary signal will be beam loss caused by the 32 micron diameter carbon wire.

  • Will also bring signals from wires up to equipment building.

    • Useful for measuring size of single mini pulse in ring.

    • Wire will get too hot for SEM during normal operations.

    • No plans to develop electronics specifically for the ring wires at this time.

    • Will use HEBT or RTBT electronics and accept its limitations.

M. Plum Slide 13


Ring wire scanner system signal levels
Ring wire scanner system signal levels removed

Rough estimate

Wire in center of beam:

Assuming 32 u dia. C wire, cross section = 0.5 barns, 2.2 cm rms beam (largest size),

there will be about

7.3E-8 protons lost per circulating proton.

Compare to background beam loss:

Assuming 1 W/m uncontrolled beam loss, equal loss around ring circumference,

there will be about

8.9E-9 protons lost per circulating proton

in the 12 m of beam line near the loss monitor.

Signal to noise is about 8:1 for wire at center of beam.

Will probably need signal averaging to get a reasonable profile.

M. Plum Slide 14


Ring wire scanner system time resolution
Ring wire scanner system time resolution removed

Beam area A is approx. proportional to turn number n.

A(n) = 0.0645 + 30.9 (n/1000) [cm2] (Liaw & Cameron, PAC 2001)

Beam size is approx. x = sqrt(A)/p

% change per turn (1/x) (dx/dn)  1/(2n).

Measurement around 100th turn must be made within 10 turns, or 10 us, to get a 5% measurement.

Measurement around 200th turn must be made within 20 turns, or 20 us, to get a 5% measurement, etc…

Loss monitor circuit and signal acquisition system must have time resolution of about 10 us or better, and a measurement accuracy of a few percent.

M. Plum Slide 15


Ring wire scanner accuracy
Ring wire scanner accuracy removed

  • Estimate of accuracy of width measurement.

    • Assuming

      • Smallest beam in ring is 2 mm rms

      • A wire positioning accuracy of 0.1 mm (same as expected for linac wire scanner actuators),

      • Absolute signal error of 10% of peak (electrical noise)

      • Relative signal amplitude error of 3% (non linearities)

      • Negligible beam position and beam width jitter

    • We expect to be able to measure the rms beam size with an accuracy of about 10%.

    • Resolution will be about half the accuracy.

M. Plum Slide 16


Rtbt wire scanner system
RTBT wire scanner system removed

  • Beam pipe size is 8” OD.

  • New 18-inch stroke actuator design. Now working with Huntington on custom design.

  • Three signal wires per actuator.

  • 32 micron diameter C wires, or 100 micron diameter SiC wires.

  • Take SEM signal off the wires.

    • Offset wires allows use of fast loss monitor as well.

  • SEM signal processing electronics to be developed by John Power.

    • Now in conceptual design.

  • BNL may also provide fast loss monitors to allow measurement of the beam profile with the beam loss method.

  • Wire heating calculations by CJ Liaw show a peak temperature of 460 oK for 2 MW beam (baseline is 1.4 MW). Wire heating is not a problem.

M. Plum Slide 17


Beam size in the rtbt
Beam size in the RTBT removed

From D. Raparia, 29/Apr/02.

M. Plum Slide 18


Wire choice and signal levels
Wire choice and signal levels removed

  • Would like electronics to be linear from about 1% of signal due to wire in center of largest bunch with the fewest protons, to about twice the signal due to the wire in the center of the smallest bunch with the most protons.

  • About 0.23 to 7000 pC for SiC wire. Several gain ranges OK.

M. Plum Slide 19


Rtbt wire scanner accuracy
RTBT wire scanner accuracy removed

  • Estimate of accuracy of width measurement.

    • Smallest beam in RTBT is 14 mm rms.

    • Assuming

      • A wire positioning accuracy of 0.3 mm (same as expected for linac wire scanner actuators),

      • Absolute signal error of 2% of peak (electrical noise)

      • Relative signal amplitude error of 1% (non linearities)

      • Negligible beam position and beam width jitter

    • We expect to be able to measure the rms beam size with an accuracy of about 7%.

    • Resolution will be about 2%.

M. Plum Slide 20


Rtbt wire scanner electronics design guidelines
RTBT wire scanner electronics design guidelines removed

  • Use existing wire scanner/faraday cup systems electronics where possible

    • Standard rack mount PC

    • Standard PCI data acquisition hardware

    • Standard LabVIEW instrument control

  • Modify existing WS analog front end to meet requirements

    • Modified gain and bandwidth (multiple gains)

    • Modified calibration source current

    • Common bias PS design

  • Status: Now working on conceptual design.

M. Plum Slide 21


Summary
Summary removed

  • Plan to use same design as linac for the 8” actuators.

  • Now working with Huntington on the 18” stroke design.

  • Will use linac electronics for HEBT units.

  • WS system in ring will be based on beam loss with back up from SEM.

  • WS system in RTBT will be based on SEM with backup from beam loss. Electronics now in conceptual design stage.

  • Designs are low risk, based on straightforward extensions to existing designs.

M. Plum Slide 22


ad