Development of the New Electron Cloud Detectors in the PS

in the PS

TE-VSC SEMINAR

Christina Yin Vallgren

on behalf of LIU-PS project

Supervisor: Paolo Chiggiato

LIU-PS coordinator: Simone Gilardoni

Vacuum, Surfaces and Coatings Group (VSC), TE-department CERN, Geneva, Switzerland

Outline

1

Introduction

Luminosity: quantity to evaluate accelerator performance

Electron Cloud (EC): one of main limitations for High

Luminosity LHC

Electron Cloud Elimination Methods

Electron Cloud Detection Methods

2

New Electron Cloud Detectors in the PS

Existing Electron Cloud monitor in the PS

Motivation of this work

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

3

Implementation in the PS

The chosen magnet: MU98

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

Summary and Outlook

Outline

1

Introduction

Luminosity: quantity to evaluate accelerator performance

Electron Cloud (EC): one of main limitations for High

Luminosity LHC

Electron Cloud Elimination Methods

Electron Cloud Detection Methods

2

New Electron Cloud Detectors in the PS

Existing Electron Cloud monitor in the PS

Motivation of this work

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

3

Implementation in the PS

The chosen magnet: MU98

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

Summary and Outlook

Luminosity:

L

[cm

−

2

s

−

1

]

Definition: a measure of the probability (rate) of particle

encounters per unit area in a collision process.

The total counting rate of a physics event

R

is given as:

R

=

L

×

σ

phys

(1)

σ

phys

: cross-section of studied physics process - very low

To increase

R

, increase luminosity

L

.

Luminosity:

L

[cm

−

2

s

−

1

]

The luminosity for two bunches with identical distribution profiles

is defined as:

L

=

fN

1

N

2

4

πσ

x

σ

z

(2)

f

: the encountering frequency

N

1

,

N

2

: the numbers of particles

(the number of bunches

×

the bunch intensity)

σ

x

,

σ

z

: the horizontal and vertical rms bunch widths

The luminosity can be increased by:

increasing the bunch intensity or the number of bunches, i.e.

N

1

,

N

2

.

increasing beam focusing at the interaction zones, i.e.

σ

x

,

σ

z

.

Electron Cloud Build-Up

In high-energy proton, positron or ion particle accelerators, an’Electron Cloud’can

develop:

initiated by:

residual gas ionization (X+p→X+_+p+e−_{). [the PS case]}

photoemission from synchrotron radiation (X+hν→X+_+e−_).

sustained by:

subsequent secondary electron emission via a beam-induced

multipactoring process if the maximumSecondary Electron Yield (SEY)of

the beam pipe surface is larger than acritical value.

Primary Electron (PE)

Surface of the beam pipe

Secondary Electron (SE) SE 1

SE 2

The surface has SEY δ = 2

Secondary Electron Yield (SEY) γ

5 ns 5 ns 20 ns 20 ns γ γ 6 / 52

Electron Cloud Build-Up

The electron cloud leads to:

dynamic pressure rise (electron stimulated desorption).

beam instabilities.

transverse emittance blow-up (bunch expansion).

thermal load in cryogenic vacuum systems.

fast or slow beam losses.

The electron cloud: one of the main limitations for the high

luminosity LHC in the future

L

=

f

N

1

N

2

4

π

σ

x

σ

z

(3)

Electron Cloud Build-Up

The electron cloud leads to:

dynamic pressure rise (electron stimulated desorption).

beam instabilities.

transverse emittance blow-up (bunch expansion).

thermal load in cryogenic vacuum systems.

fast or slow beam losses.

The electron cloud: one of the main limitations for the high

luminosity LHC in the future

L

⇓

=

f

N

1

↓

N

2

↓

4

π

σ

x

↑

σ

z

↑

(4)

Electron Cloud Elimination Methods

Elimination of electron cloud in accelerators Mechanical modification in vacuum chambers Clearing electrodes (need of additional electrical feedthroughs) Chambers with grooves and slots (reduction of beam pipe aperture)

Chambers with solenoid winding (not applicable in the cases of e.g. dipoles)

Modification of material properties in

vacuum chambers

Thin Film Coatings Surface conditioning (beam scrubbing, graphitization)

TiN (works under the effect of conditioning in-situ) TiZrV (NEG) (activation at 180⁰C in-situ) Amorphous carbon thin film •δmax ~ 1.0

•No need of bakeout •Slow ageing •Large scale production

Electron Cloud Detection Methods

EC detection

Local EC measurements

Button-type

pickups Strip detectors

Integrated EC over a long section Microwave transmission Phase shift vs total beam intensity New proposal (photon detection) • Simple, fast • Used in the PS and the SPS straight sections

• Simple, fast, position • Used in the SPS

straight sections

Implemented in

the SPS dipole Measured in the LHC

Outline

1

Introduction

Luminosity: quantity to evaluate accelerator performance

Electron Cloud (EC): one of main limitations for High

Luminosity LHC

Electron Cloud Elimination Methods

Electron Cloud Detection Methods

2

New Electron Cloud Detectors in the PS

Existing Electron Cloud monitor in the PS

Motivation of this work

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

3

Implementation in the PS

The chosen magnet: MU98

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

Summary and Outlook

Existing Electron Cloud monitor in the PS

First observation of EC in the PS in 2000s.

First electron cloud set-up in PS straight section 98, 2007 - bare st.st. vacuum chamber

Second set-up in PS straight section 84, 2008 - a-C coated st.st. vacuum chamber

F. Caspers, T. Kroyer, E. Mahner

Plan for the LIU-PS electron cloud studies

So far, nodirectelectron cloud monitor in any main magnet

A dipole in straight section doesnot represent the real situation in a main

magnet:

Nohigh magnetic field

Noramp of magnetic field

In straight sections with

C-magnet

In a dipole magnet Direct Electron Cloud Measurements

?

Plan for the LIU-PS electron cloud studies

Measurements of electron cloud in arealmagnet, will provide:

Predictionof the EC build-up distribution in the PS magnets for higher intensity beams in the frame of the upgrade program.

Validationof the EC simulation models and codes.

In straight sections with

C-magnet

In a dipole magnet Direct Electron Cloud Measurements

Development of New Electron Cloud

Monitors in the PS main magnet 1. Development 1 2. Development 2

Development 1: Shielded button-type pick-up

- Design

Idealposition for a pick-up: on the

top/bottom of vacuum chamber due to magnetic field

Not possibledue to space limitation in the

PS main magnet

PS magnet vacuum chamber

LHC beam

B

e- e-

shielded pick-up

DN40 flange placed 30◦_to

the bottom part of the vacuum chamber

Use radial steering to move the beam towards the EC pick-up. (30mm possible provided by simulations)

Development 1: Shielded button-type pick-up

- Design

Idealposition for a pick-up: on the

top/bottom of vacuum chamber due to magnetic field

Not possibledue to space limitation in the

PS main magnet DN40 flange placed 30◦to

the bottom part of the vacuum chamber

Use radial steering to move the beam towards the EC pick-up. (30mm possible provided by simulations)

Development 1: Shielded button-type pick-up

- Design

Idealposition for a pick-up: on the

top/bottom of vacuum chamber due to magnetic field

Not possibledue to space limitation in the

PS main magnet

DN40 flange placed 30◦_to

the bottom part of the vacuum chamber

Use radial steering to move the beam towards the EC pick-up. (30mm possible provided by simulations)

Shield Stainless steel plate coated by Ag?

PS magnet vacuum chamber

Different types of PS beam

Development 1: Shielded button-type pick-up

- Simulations

SCALA analysis tool within OPERA-3D to validate current

measurement efficiency

Beam displacement of 30 mm: 3.3

µ

A arrives on the pick-up

40 mm width electron cloud flux of 2x10-4 _A/mm2

B (y) = 1.2 T

Bias of +60 V on the pick-up

Electron cloud current arrives on the pick-up = 16.18 nA

B (y) = 1.2 T 40 mm width electron cloud flux of 2x10-4 _A/mm2

Bias of +60 V on the pick-up Electron cloud current arrives on the pick-up = 3.3 mA

Assume:

The LHC type beams creates a flux of electron cloud: Width of 40 mm and

Current density of 2×10−6_A/mm2_.

Dipole magnetic field: 1.2 T. Pick-up biase: +60 V.

Development 2: Electron-photon Emission

- Theory

Phenomenology of electrons impinging on a surface

e-

Sample Excited volume X-rays

UV, IR and visible cathodoluminescence Secondary electrons Auger electrons Back-scattered electrons

Schematic of the principle of metal cathodoluminescence

Development 2: Electron-photon Emission

- Theory

Phenomenology of electrons impinging on a surface

e-

Sample Excited volume X-rays

UV, IR and visible cathodoluminescence Secondary electrons Auger electrons Back-scattered electrons

Schematic of the principle of metal cathodoluminescence Einitial Evacuum Efinal Efermi level e- ELUMO EHOMO

LUMO : lowest unoccupied molecular orbital

HUMO: highest unoccupied molecularorbital Secondary electrons

(escape from the surface)

Secondary electrons (fall into unoccupied states)

h𝜐

Primary electrons ~300 eV

Unoccupied states

Occupied states

Development 2: Electron-photon Emission

- Theory => Application

Corrected cathodoluminescence spectra of clean Cu at electron energies 300 eV and 1 keV.

B. Papanicolaou and et. al., J. Phys. Chem. Solids, vol. 37, pp. 403-409, 1976.

Cathodoluminescence of copper and nickel surfaces 405

i- !- I I I I I 6 5 4 3 ENERGY (eV) 2 COPPER Clean Surface 300 eV Uncorrected Spectrum L

Fig. 2. Cathodoluminescence spectrum of clean Cu. The spectrum is uncorrected for the system response.

COPPER Clean Surface Corrected Spectrum I, 1 ,,I,,,,,,,,,,,,,,, 200 300 400 500 600 WAVELENGTH (nm)

Fig. 3. Corrected cathodoluminescence spectra of clean Cu at electron energies 300 eV and 1 keV. The 230 nm peak appears in every uncorrected lumines-

cence spectrum of copper and nickel and it is independent of the surface condition. This peak does not appear in the corrected spectra. It is due to an apparent drop in the transmittance of quartz at 240nm. Filters, lenses, P-M tube window and P-M chamber window are all made of quartz.

A comparison of the luminescence spectra for both Cu and Ni before and after oxidation (Figs. 3,6-S) shows that the 520nm peak can be associated unequivocally to the existence of an oxide layer. The peak disappeared after proper cleaning of the surface. This result substantiates our contention that thin films of insulators and semicon- ductors can luminesce much more efficiently than metals,

so for any reliable measurement of luminescence from metal the surface must be clean.

This 520nm green luminescence, which appears on oxidized surfaces of Cu and Ni, is also observed on oxidized surfaces of Ta and stainless steel. It is not observed, however, on cleaved surfaces of MO&, a layer compound with extremely inert surface property. The emitted light therefore is most likely characteristic of 02- ions rather than of the various compounds.

The green luminescence is visible in a dark room. The light is not emitted uniformly from the surface, rather, it takes the form of a uniformly distributed high density of fine points covering the whole surface, with the emission at a few scratches, introduced during mechanical polishing,

EC measurement via electron-photon emission.

Electrons in EC has relatively low energies (300 eV).

Expected photon wavelength with 300eV electrons: 200nm-700nm (visible).

Expected photon energies: from 2 eV to 5eV.

Development 2: Electron-photon Emission

- Theory => Application

Corrected cathodoluminescence spectra of clean Cu at electron energies 300 eV and 1 keV.

B. Papanicolaou and et. al., J. Phys. Chem. Solids, vol. 37, pp. 403-409, 1976.

Cathodoluminescence of copper and nickel surfaces 405

i- !- I I I I I 6 5 4 3 ENERGY (eV) 2 COPPER Clean Surface 300 eV Uncorrected Spectrum L

Fig. 2. Cathodoluminescence spectrum of clean Cu. The spectrum is uncorrected for the system response.

COPPER Clean Surface Corrected Spectrum I, 1 ,,I,,,,,,,,,,,,,,, 200 300 400 500 600 WAVELENGTH (nm)

Fig. 3. Corrected cathodoluminescence spectra of clean Cu at electron energies 300 eV and 1 keV. The 230 nm peak appears in every uncorrected lumines-

cence spectrum of copper and nickel and it is independent of the surface condition. This peak does not appear in the corrected spectra. It is due to an apparent drop in the transmittance of quartz at 240nm. Filters, lenses, P-M tube window and P-M chamber window are all made of quartz.

A comparison of the luminescence spectra for both Cu and Ni before and after oxidation (Figs. 3,6-S) shows that the 520nm peak can be associated unequivocally to the existence of an oxide layer. The peak disappeared after proper cleaning of the surface. This result substantiates our contention that thin films of insulators and semicon- ductors can luminesce much more efficiently than metals,

so for any reliable measurement of luminescence from metal the surface must be clean.

This 520nm green luminescence, which appears on oxidized surfaces of Cu and Ni, is also observed on oxidized surfaces of Ta and stainless steel. It is not observed, however, on cleaved surfaces of MO&, a layer compound with extremely inert surface property. The emitted light therefore is most likely characteristic of 02- ions rather than of the various compounds.

The green luminescence is visible in a dark room. The light is not emitted uniformly from the surface, rather, it takes the form of a uniformly distributed high density of fine points covering the whole surface, with the emission at a few scratches, introduced during mechanical polishing,

EC measurement via electron-photon emission.

Electrons in EC has relatively low energies (300 eV).

Expected photon wavelength with 300eV electrons: 200nm-700nm (visible).

Expected photon energies: from 2 eV to 5eV.

PS magnet vacuum chamber

LHC types beam B e- e- hν hν hν hν hν hν hν Optical window Photomultiplier 22 / 52

Development 2: Electron-photon Emission

- Theory => Application

Synchrotron Radiation levels in different accelerators.

The UV and visible photons in the PS are out of the SR range. Electron-photon Emission method can be applied the PS.

by Roberto Kersevan 700nm 200nm

Development 2: Electron-photon Emission

- Theory => Application

Synchrotron Radiation levels in different accelerators.

The UV and visible photons in the PS are out of the SR range. Electron-photon Emission method can be applied the PS.

by Roberto Kersevan 700nm 200nm

Development 2: Electron-photon Emission

- Experimental set-up in the lab

1 _{Electron gun: low temperature BaO}

cathode (1150K)

2 _{Gridanddeflection: prevent the}

electrons arrive on the sample.

3 _{Sample: +18 V.}

4 _{Quartz window: 200-2000 nm}

transmission 100%.

5 _{Collimating lens: optimized for}

200-2500 nm.

6 _{Optical fiber: transfer the light from}

the system to the spectrometer.

7 _{Andor Spectrograph: with CCD}

camera (200-770 nm).

Electron bombard stainless steel surface to validate emitted photons and in which

ranges they are.

1. Electron gun with BaO cathode Low light emitter (1150K)

3. Sample Bias of +18V 4. Quartz window 5. Collimating lens 6. Optical fiber 7. Andor Shamrock Spectrograph Computer 7. Andor iDus spectroscopy camera 200-770nm 𝑒𝑒− 20o 2. Grid 2. Deflection 2. Collector 25 / 52

Development 2: Electron-photon Emission

- Experimental set-up in the lab

1 _{Electron gun: low temperature BaO}

cathode (1150K)

2 _{Gridanddeflection: prevent the}

electrons arrive on the sample.

3 _{Sample: +18 V.}

4 _{Quartz window: 200-2000 nm}

transmission 100%.

5 _{Collimating lens: optimized for}

200-2500 nm.

6 _{Optical fiber: transfer the light from}

the system to the spectrometer.

7 _{Andor Spectrograph: with CCD}

camera (200-770 nm).

Electron bombard stainless steel surface to validate emitted photons and in which

ranges they are.

1. Electron gun with BaO cathode Low light emitter (1150K)

3. Sample Bias of +18V 4. Quartz window 5. Collimating lens 6. Optical fiber 7. Andor Shamrock Spectrograph Computer 7. Andor iDus spectroscopy camera 200-770nm 𝑒𝑒− 20o 2. Grid 2. Deflection 2. Collector 26 / 52

Development 2: Electron-photon Emission

- Experimental set-up in the lab

1 _{Electron gun: low temperature BaO}

cathode (1150K)

2 _{Gridanddeflection: prevent the}

electrons arrive on the sample.

3 _{Sample: +18 V.}

4 _{Quartz window: 200-2000 nm}

transmission 100%.

5 _{Collimating lens: optimized for}

200-2500 nm.

6 _{Optical fiber: transfer the light from}

the system to the spectrometer.

7 _{Andor Spectrograph: with CCD}

camera (200-770 nm).

Electron bombard stainless steel surface to validate emitted photons and in which

ranges they are.

1. Electron gun with BaO cathode Low light emitter (1150K)

3. Sample Bias of +18V 4. Quartz window 5. Collimating lens 6. Optical fiber 7. Andor Shamrock Spectrograph Computer 7. Andor iDus spectroscopy camera 200-770nm 𝑒𝑒− 20o 2. Grid 2. Deflection 2. Collector 27 / 52

Development 2: Electron-photon Emission

- Experimental results in the lab

Cathodoluminescence spectra of an oxidized stainless steel at electron energy of 300 eV. (The spectra are uncorrected for the system response.)

Averaging 10 measurements of 60 s integration time with 5 accumulations.

The photon counts seems to beproportionalto the electron current on the

sample.

The experimentally estimated yield on st.st. of5×10−11_{ph/elfor E = 300 eV.}

100 200 300 400 500 600 700 800 −50 0 50 100 150 200 250 300 350 400

Oxidized stainless steel, I(sample)=3µA/2mm2

Wavelength [nm]

Intensity [Counts for 60s with 5 accumelations]

Raw data of 10 measurements Smooth data 100 200 300 400 500 600 700 800 −100 0 100 200 300 400 500 600 700 800

Oxidized stainless steel, I(sample)=9µA/2mm2

Wavelength [nm]

Intensity [Counts for 60s with 5 accumelations]

Raw data of 10 measurements Smooth data

Outline

1

Introduction

Luminosity: quantity to evaluate accelerator performance

Electron Cloud (EC): one of main limitations for High

Luminosity LHC

Electron Cloud Elimination Methods

Electron Cloud Detection Methods

2

New Electron Cloud Detectors in the PS

Existing Electron Cloud monitor in the PS

Motivation of this work

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

3

Implementation in the PS

The chosen magnet: MU98

Development 1: Shielded button-type pick-up

Development 2: Electron-photon Emission

Summary and Outlook

Which magnet to choose?

Possible magnets to choose:

LS1 => Good moment to benefit the opportunity

Our preferable MU is in Sector 9 Sector 9: Radiation cool

MU98: next to the existing EC monitor

in SS98

Standard stainless steel vacuum chamber.

Never refurbished.

Cabling to 355/R-017: <50m. Benefit the existing electronics. Radial steering possible: beam can be moved towards the pick-up by 30 mm. MU55 EC monitor SS98 355/R-017 30 / 52

Implementation in the PS MU98 vacuum chamber

Two flanges are added to the MU98 vacuum chamber: DN35 for installation of shielded pick-up. DN63 for installation of optical window.

DN63: optical window

DN35: shield pick-up

Development 1: Shielded button-type pick-up

- 3D design

BNC coaxial connector DN40 CF Flange with feedtrough from LESKER St. Steel arm welded on flange

Al2O3 ceramic part Silver painted on blue surfaces

St. Steel sheet th 0.2mm welded on the support

Holes Ø1mm / space 2mm Contacts with

vacuum chamber

St. Steel parts

ELECTRON PICK-UP FOR MU98 VACUUM CHAMBER

Development 1: Shielded button-type pick-up

- Pick-up

Grid ϕ = 1 mm

DN40 with feedthrough Ceramic block with silver painting

Adjustable arm to ease the insertion

Development 1: Shielded button-type pick-up

- Pick-up

Development 1: Shielded button-type pick-up

- Signal Treatment

Similar electronics used for the existing pick-up in the SS98 will be applied.

System bandwidth (0.045-350 MHz) is mainly limited by cable

attenuation.

Input and output signals Signal read-out by oscilloscope

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 x 10−6 0 0.5 1 1.5 Time [s]

EC arrived on the pick−up [

µ

A] _{Assumed EC arrived on the pick−up = 1 µA}

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 x 10−6 0 5 10 15 Time [s] Output voltage [ µ V] Detected Voltage 35 / 52

Development 1: Shielded button-type pick-up

- Signal Treatment: Previous results in SS98

25ns 72 bunches nominal LHC beam

1.21×1011_p/b 0 0.5 1 1.5 2 x 10−6 −0.02 0 0.02 time [s]

pick−up signal [a.u.]

0 0.5 1 1.5 2 x 10−6 0.1 0.2 0.3 time [s]

electron cloud signal [a.u.]

50ns 36 bunches nominal LHC beam

1.4×1011_p/b 0 0.5 1 1.5 2 x 10−6 −0.02 −0.01 0 0.01 0.02 time [s]

pick−up signal [a.u.]

0 0.5 1 1.5 2 x 10−6 −0.02 0 0.02 time [s]

electron cloud signal [a.u.]

Development 2: Electron-photon Emission

- Input used for estimation of the number of expected photons

1. Experimental electron-photon yield = 5x10-11 ph/el (stainless steel)

2. Reflectivity of stainless steel: 20-50% (assume 40%)

=> Sticking factor = 0.6

3. Electron cloud density = 1 µA/mm2 4. Electron cloud area = 8.4x102 mm2

Development 2: Electron-photon Emission

- Monte Carlo simulation for estimation of the number of expected photons

Photon yield of 1.2% 1575 photons expected

• Electron bombardment area = 8.4x102 mm2

• # of electrons generated by beam (ref Giovanni & co) = 8.4x102 mm2 x 1e-6 C/s mm2/1.6e-19C = 5.25x1016 electron/s • Experimental radiation yield = 5x10-11 ph/el (stainless steel)

• # of photons emitted by electrons = 2.625x106 photons • # of photon reaches detector =

1.2% x 2.625x106 _{photons= 3.15x10}4 _photons/s

• During the last 40-50ms electron cloud development of the PS

•1575 photons can be detected!

Photon yield of 8% with Al/MgF2

coating

10500 photons expected

• Electron bombardment area = 8.4x102 _mm2

• # of electrons generated by beam (ref Giovanni & co) = 8.4x102 mm2 x 1e-6 C/s mm2/1.6e-19C = 5.25x1016 electron/s • Experimental radiation yield = 5x10-11 _{ph/el (stainless steel)}

• # of photons emitted by electrons = 2.625x106 _photons

• # of photon reaches detector = 8% x 2.625x106 photons = 2.1x105 photons/s

• During the last 40-50ms electron cloud development of the PS

•10500 photons can be detected!

High reflectivity coating (85% Mylar foil with Al/MgF2)

Development 2: Electron-photon Emission

- Monte Carlo simulation for estimation of the number of expected photons

Photon yield of 8% with Al/MgF2

coating

10500 photons expected

• Electron bombardment area = 8.4x102 _mm2

• # of electrons generated by beam (ref Giovanni & co) = 8.4x102 mm2 x 1e-6 C/s mm2/1.6e-19C = 5.25x1016 electron/s • Experimental radiation yield = 5x10-11 _{ph/el (stainless steel)}

• # of photons emitted by electrons = 2.625x106 _photons

• # of photon reaches detector = 8% x 2.625x106 photons = 2.1x105 photons/s

• During the last 40-50ms electron cloud development of the PS

•10500 photons can be detected!

High reflectivity coating (85% Mylar foil with Al/MgF2)

# of photons arriving on the DN63 window 0 20 40 60 80 0 20 40 60 80 0 0.01 0.02 0.03 0.04 0.05

along vertical axis Photons detected on the DN63 quartz window

along horizontal axis

Photon detector yield

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 39 / 52

Development 2: Electron-photon Emission

- Multi-Channel Plate - Photon Multiplier Tube (MCP-PMT)

Multi-channel plate PMT from Photonis is chosen

due to high magnetic field (1.2T)

Lab measurement set-up to validate the MCP-PMT BI lab set-up Pulsed Laser f = 1/25ns Filter Photonis MCP-PMT UV range 70000 e-/ph Hamamatsu High speed amplifier

x63 (to reduce laser beam Intensity) Ortec Amplifier + timing discriminator Discriminate 20mV LeCroy oscilloscope 2GHz HV power supply -2400V LV power supply +15 V 40 / 52

Development 2: Electron-photon Emission

- PS measurement set-up

Magnetic field map in MU98

MCP-PMT: magnetic field direction dependency

Development 2: Electron-photon Emission

- PS measurement set-up

Magnetic field map in MU98

0 0.2 0.4 0.6 0.8 0 0.1 0.2 0.3 0.4 0 0.5 1 1.5 2 x−axis (m) Magnetic field in MU98

y−axis (m)

Magnetic field (T)

MCP-PMT: magnetic field direction dependency

Development 2: Electron-photon Emission

- PS measurement set-up

PS measurement set-up PS tunnel 355-R-017 160mm 20mm 300mm 100mm 50mm Lens 1 f1 = 100mm Φ = 50mm _{UV mirror} Φ = 50mm Lens 2 f1 = 40mm Φ = 50mm MCP-PMT AMP x63 Electron cloud 40 mm Electron cloud 40 mm 70mm Φ = 60mm HV power supply -2400V Discriminator 20 mV LeCroy oscilloscope 2GHz LV power supply +15 V HV -2400V: BNC1 LV +15V: BNC2 output: BNC3 Black box

Trigger at C2460ms in the PS cycle Measure the last 50ms

ZNQCVP-63-NM ZNQCVP-63-NM

Development 2: Electron-photon Emission

- PS measurement set-up

Black box installed in the PS: Main magnet 98 Amplifier x63 Lens 1: f1 = 100mm UV mirror Lens 2: f2 = 40mm Multi-channel plate PMT 44 / 52

Summary and Outlook

A project from the beginning to the end.

A collaboration with different people from different groups.

Still some work to be done.

Improvement is also needed.

First nominal beam in the PS planned on 14th of July.

More results to come soon...

Summary and Outlook

A project from the beginning to the end.

A collaboration with different people from different groups.

Still some work to be done.

Improvement is also needed.

First nominal beam in the PS planned on 14th of July.

More results to come soon...

Summary and Outlook

A project from the beginning to the end.

A collaboration with different people from different groups.

Still some work to be done.

Improvement is also needed.

First nominal beam in the PS planned on 14th of July.

More results to come soon...

This project has been collaboration with different people from different groups,

thanks to Everyone who has been involved in this project.

Special thanks to:

Holger

,

Mounir

,

Wil

,

Ivo

,

Luigi

,

Phillippe

and

Paul

2

for all the

supports for the experimental set-ups, both in the lab and in the PS.

Mauro

,

Jose

,

Marton

,

Daniel Schoerling

(TE-MSC),

Simone Gilardoni

/

Guido Sterbini

/

Giovanni Rumolo

/

Giovanni Iadarola

(BE-ABP) for all

the inspiring discussions and simulations needed for this work.

Enrico Bravin

/

Marcus Palm

/

Stefano Mazzoni

(BE-BI),

Thomas

Schneider

/

Thierry Gys

(PH-DT) for the discussion concerning

photo-detection in the PS and the lending of their lab instrumentation.

The CERN Drawing Office (

Teddy Capelli

and

Cedric Eymin

) and Main

Workshop for their collaboration and effort in designing and fabricating all

new vacuum equipment during the LS1.

Backup Slide

PS beam production

h=7 b. sp. ≈ 330 ns (4 - 6 b.) b. sp.≈100 ns (18 b.) h=21 h=42 b.sp.=50 ns (36 b.) h=84 b.sp.=25 ns (72 b.) Triple

splitting splittingDouble splittingDouble shorteningBunch

Backup Slide

PS beam production

h=7 b. sp. ≈ 330 ns (4 - 6 b.) b. sp.≈100 ns (18 b.) h=21 h=42 b.sp.=50 ns (36 b.) h=84 b.sp.=25 ns (72 b.) Triple

splitting splittingDouble splittingDouble shorteningBunch

Before the last bunch splitting e-cloud not expected nor observed

Backup Slide

PS beam production

h=7

b. sp. ≈ 330 ns (4 - 6 b.) b. sp.≈100 ns (18 b.) h=21

Triple

splitting splittingDouble splittingDouble shorteningBunch

0 10 20 30 40 50 60 50 150 250 300 200 100 40 M H z R F V o lt ag e [ kV ] Time [ms] h=42 b.sp. = 50 ns (36 b.) b.sp. = 25 ns (72 b.) h=84 Double splitting Adiabatic shortening Bunch rotation b.l.≈14 ns 11 ns 4 ns 51 / 52

Backup Slide

PS beam production

h=7

b. sp. ≈ 330 ns (4 - 6 b.) b. sp.≈100 ns (18 b.) h=21

Triple

splitting splittingDouble splittingDouble shorteningBunch

0 10 20 30 40 50 60 50 150 250 300 200 100 40 M H z R F V o lt ag e [ kV ] Time [ms] h=42 b.sp. = 50 ns (36 b.) b.sp. = 25 ns (72 b.) h=84 Double splitting Adiabatic shortening Bunch rotation b.l.≈14 ns 11 ns 4 ns

E-cloud expected and observed