Leir schottky system and experimental results j tan ab bdi
This presentation is the property of its rightful owner.
Sponsored Links
1 / 22

LEIR Schottky system and Experimental Results J.TAN AB/BDI PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on
  • Presentation posted in: General

LEIR Schottky system and Experimental Results J.TAN AB/BDI. Outline. LHC ion injector chain LEIR Machine Schottky Pick-Ups Commissioning with : Oxygen ions O 4+ Lead ions Pb 54+ Summary. LHC Filling Scheme : Pb 54+ ions. 200 e m A. Pb 27+. 27+. 82+. 54+. 54+. Pb. Pb.

Download Presentation

LEIR Schottky system and Experimental Results J.TAN AB/BDI

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


Leir schottky system and experimental results j tan ab bdi

LEIR Schottky system and Experimental ResultsJ.TANAB/BDI

Jocelyn TAN CERN AB / BI


Outline

Outline

  • LHC ion injector chain

  • LEIR

    • Machine

    • Schottky Pick-Ups

  • Commissioning with :

    • Oxygen ions O4+

    • Lead ions Pb54+

  • Summary

Jocelyn TAN CERN AB / BI


Lhc filling scheme pb 54 ions

LHC Filling Scheme : Pb54+ ions

200 emA

Pb 27+

27+

82+

54+

54+

Pb

Pb

Pb

Pb

ECR

4.2 MeV/u,

b=0.095

rep. rate 1 to 5Hz

Energy ramping

cavity Dp/p~0.4%

LINAC3

RFQ

LEIR

  • stacking of 9x108 ions at 4.2 MeV/u

  • accel. to 72 MeV/u

  • 2 bunches of 4.5x108 ions each

  • cycle length 3.6s

592 bunches

~

10mn filling time per ring.

7.107 /bunch

2.76TeV/u, L = 1027 cm-2 s-1

LHC

*accel. to

5.9 GeV/u

*Double bunch splitting

SPS

*4 pairs of bunchlets per 3.6s

PS

~13 PS inj./ SPS cycle

1 ej./1. mn at 177GeV/u

Jocelyn TAN CERN AB / BI


Leir machine 1

LEIR Machine (1)

Nominal Lead Ions Cycle : 3.6s

Extraction

1.2

B[ T ]

72 MeV/u

1.0

multi-turn injection 200ms

0.8

Main dipole field [T]

0.6

Electron cooling + Stacking

Acceleration

0.4

0.2

4.2 MeV/u

t[ms]

0.0

0

500

1000

1500

2000

2500

3000

3500

ejection

injection

  • Injection repetition rate : 1 to 5 Hz

  • Beam unbunched for 1600ms

  • Schottky signals are essential for diagnostics and controlling phase-space cooling efficiency

Jocelyn TAN CERN AB / BI


Leir machine 2

LEIR Machine (2)

extraction point

injection line

Electron cooler

Jocelyn TAN CERN AB / BI


Stripline electrode

Stripline electrode

t2+t1

t2

t1

A B

  • Striplines electrodes

  • Z0 = 50

  • Matched lines

L

picking up the signal

upstream the line

A

B

picking up the signal

donwstream the line

Jocelyn TAN CERN AB / BI


Leir travelling wave mode

LEIR : Travelling-Wave mode

  • Travelling-Wave Striplines for lowenergyparticles

P ~ (Nstripxi0)2

delay

delay

3i0

2i0

i0

Jocelyn TAN CERN AB / BI


Leir travelling wave mode1

LEIR : Travelling-Wave mode

delay

delay

  • Travelling-Wave Striplines for lowenergy particles

Beam

delay

delay

Superposition of currents

Good S/N ratio

Hybrid

S port D port

Total power ~ (Nstripi0)2

Jocelyn TAN CERN AB / BI


Leir parallel combination

LEIR : Parallel combination

  • Monitor backward signal : for high (any) energy particles

Hybrid

Hybrid

Hybrid

i0

i0

i0

delay1

delay2

Combiner

Total power ~ Nstripxi02

Jocelyn TAN CERN AB / BI


Schottky pick ups layout

Schottky Pick-Ups Layout

UCV22-TW

EXTRACTION : Parallel mode

INJECTION : Travelling Wave mode

Vertical :

8 pairs of stripline-electrodes

Horizontal and Longitudinal :

24 pairs of stripline-electrodes

Vertical :

6 pairs of stripline-electrodes

Horizontal and Longitudinal :

24 pairs of stripline-electrodes

Jocelyn TAN CERN AB / BI


In the control room

In the control room...

75 dB

Pick-Up

-45

-55

-65

-75

-85

-95

-105

Dp/p = 4.10-3

N=2.25x108 Lead ions

-145 dBm/Hz

-70 dBm/Hz

noise level of the spectrum analyser = -140 dBm/Hz

Inj.

trigger

100th harmonic

at 36 MHz

reduced thermal noise = -177 dBm/Hz

Resolution BW = 1.5 kHz

Peak signal = - 38 dBm

( i.e. 2.7 mV peak)

Aug. 2007 : new Spectrum analysers + remote desktop

Jocelyn TAN CERN AB / BI


Commissioning with o 4 ions oct nov 2005

Commissioning with O4+ ions : Oct.-Nov. 2005

  • Expected longer vacuum life-time than with Lead ions (lower cross section for charge exchange processes with the residual gas)

  • O4+ and Pb54+ have very close Z/A Nearly same beam rigidity for both ion species

  • Results and observations

  • Unexpected shorter lifetime : vac. leaks + desorption

  • Fast losses coupled w/ transverse “activities” observed :

    coupling impedances

    ions trapped in potentials created by e- beam

  • Interpretation of beam cooling not straightforward

  • frev = 363.3 kHz

  • Injection momentum spread ~ 4x10-3

  • Qh = 1.795 Qv = 2.604

Longitudinal plane

Horizontal spectrum

Vertical spectrum

(100+qh ).f0

(50-qv ).f0

(50+qv ).f0

(101-qh ).f0

50.f0

99.f0100.f0101.f0

Jocelyn TAN CERN AB / BI


Commissioning with pb 54 ions 2006 2007 nominal scheme

Commissioning with Pb54+ ions : 2006-2007 : Nominal Scheme

Spectrogram of the momentum cooling during stacking on the injection front porch. The vertical and horizontal axis denote time (1.6 s total from top to bottom); and momentum spread (1% full scale) respectively. There are 5 injections-cooling stacking sequences every 300ms

7.8x108 cold ions before bunching

~30% off wrt Nominal value

Jocelyn TAN CERN AB / BI


Momentum

MOMENTUM

full span is equivalent to Dp/p = 1%

Jocelyn TAN CERN AB / BI


Vertical

VERTICAL

full span is equivalent to Dp/p = 1%

Jocelyn TAN CERN AB / BI


Summary

Summary

  • Schottky system in LEIR is fully operational

  • GUI displaying e.g. tune vs time is expected for the next run

  • The pick-ups for high momentum have been commissioned, but never used

Jocelyn TAN CERN AB / BI


Performances nominal

PERFORMANCES :NOMINAL

Sigma[mm]

30

H

20

10

0

V

Courtesy M. CHANEL, G. TRANQUILLE

Jocelyn TAN CERN AB / BI

Evolution of beam dimensions during injection and cooling process


Putting numbers injection

Putting numbers : injection

  • Number of particles 2.25x108 ions

  • In all formula, replace “e” by “Ze”

  • Qh / Qv 1.82 / 2.72

  • Betatron function bh/bv = 6.5 / 5.5

  • Striplines geometry 16cm/13cm

  • Transfer function

Jocelyn TAN CERN AB / BI


Injection longitudinal spectrum

Injection: Longitudinal spectrum

After e-cooling

Injection

6

Jocelyn TAN CERN AB / BI


Injection transverse spectra

Injection : Transverse spectra

Horizontal

e*h= 0.3 p.mm

e*h= 1.7 p.mm

Vertical

e*v= 0.25 p.mm

e*v= 1 p.mm

Jocelyn TAN CERN AB / BI


Equivalent input noise 1

Equivalent input noise (1)

  • Noise Figure of an amplifier : NF [dB]

    • Passive components

    • Transistors : Shot noise

    • FETs : voltage and current noise

    • Equivalent noise source

real

G

+

RinTeq

real

ideal

xG

Ieq(f)

Rs, T

ideal

Rs

real

real world equivalent circuit

  • Johnson noise of a resistor:

R

real

R, T iR(f)

ideal

  • Equivalent input noise

Jocelyn TAN CERN AB / BI


Equivalent input noise 2

Equivalent input noise (2)

G

+

RinTeq

LNA

NF1

50 Load

Eq. Noise Ieq(f)

[pA/Hz1/2]

Low Noise Amplifier

Zin = 50

NF1 = 1.2 dB NF1

T = Room Temp.

293K 10.3

LNA

NF

Ieq (f)

Teq = 93K

5.8

With active loads

the input noise is

decreased by ~-6dB

LN2 5.3

Teq

10K 1.9

Jocelyn TAN CERN AB / BI


  • Login