leir schottky system and experimental results j tan ab bdi n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
LEIR Schottky system and Experimental Results J.TAN AB/BDI PowerPoint Presentation
Download Presentation
LEIR Schottky system and Experimental Results J.TAN AB/BDI

Loading in 2 Seconds...

play fullscreen
1 / 22

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


  • 166 Views
  • Uploaded on

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.

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


Download Now 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
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