Pepper Pot monitor for the Linac3 ITL Line

MSWG– 13- Aug -2013

F.Roncarolo, A.Ravni

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Introduction

SCOPE Provide emittance measurement after the ITL spectrometer

CONSTRAINTS Only space available is diagnostic tank presently hosting slit+ SEM grid

+ Farady cup Beam not round Limited resources in BI

PROPOSED SOLUTION Buy a commercial pepper pot system to be integrated into the

diagnostics tank at the place of the SEM grid

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Linac 3 - LEBT

Existing Diagnostic Tank

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ITL

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ABP - Request

1. single charge state ion beam from an ECR ion source after the spectrometer

2. intensity: 200 eμA for Pb29+, but could be >1emA for other (lighter) ions3. time structure: 10Hz, 50ms heating pulses with beam extracted, plus ~2ms

afterglow4. beam energy: 2.5 keV/u for interesting beam, other charge states/species

from same potential

5. dimensions of the beam: x = +-1.5 mm, xp = +-130 mrad, y = +-9 mm, yp= +-9.5 mrad,

6. nominal lead beam, 100% beam envelope

7. the system needs to be retractable from the beam line8. the system should be made of UHV compatible components

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Offers

Detlef Kuchler contacted - Helmholtz-Zentrum Dresden-Rossendorf- Kernfysisch Versneller Instituut (KVI), Groningen, the Netherlands

- PANTECHNIK S.A. , France- Commercialization of KVI system, especially developed to meas. Emittance

at ECR sources front-end- Pepperpot ‘pinhole’ mask, tungsten foil with a vertical row of 20 holes

(20um diameter, 2mm pitch, changeable at the moment of ordering)– X,X’ + Y,Y’ reconstruction by scanning the vertical row along the hor

axis- MCP plate + phosphor screen- CCD camera- Control-Acquisition-Analysis SW

PANTECKNIK offer recognized as the best (D.Kuckler, R.Scrivens, E.Bravin, J-J.Gras, F.Roncarolo) started to investigate integration into existing tank (A.Ravni, BI-ML)

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PANTECHNIK system

BEAM

Pepper pot plateMCP, PHOSPHOR

Mirror

Camera

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Integration into existing tank (A.Ravni)

Faraday Cup

SLITPepper Pot

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Integration into existing tank (A.Ravni)

Variable Diameter

S-Shaped

Faraday Cup

SLIT

Faraday Cup

SLIT

Pepper Pot

Pepper Pot

This tank design

• verified with main workshop• allows keeping SLIT and FC

mechanisms as existing

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Integration into existing tank (A.Ravni)

Tank modifications w.r.t. existing one- Slit moved forward of 50 mm (maximum allowed, A.Lombardi)- Tank diameter reduced of 46 mm (300 254 mm)- Tank length increased of 70 mm (310 380 mm) shorter bellow on 1

side) - to avoid interference w. Pepper Pot

- FC side diameter opening changed - Slit side tank with S-shape (angle)

Still to be decided: interconnection to upstream pipe, being discussed with Vacuum (J.Hansen), to avoid having bellow directly soldered on pipe (as proposed by BI-ML)

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Timing and gating13

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Linac3 requirements: 50ms pulse + 2 ms (max) afterglow, 10Hz rep. rate- want to sample afterglow emittance with 100us (max) sampling rate

Pantechnik proposed:-Camera: SONY XCL-U1000

shutter trigger rate 15Hz (max)shutter gate length from 100us to 66ms

-Phosphor: P431.2 ms decay time

So, we looked at alternative phosphors-R42, P47 fast enough-P47 better radiation hard

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Camera sensitivity matches better R42 than P47, but P47 has twice the emissivity (see table previous slide)

Conclusion: Pantechnik accepted to provide P47 for same price as P43

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Conclusions

Commercial Pepper Pot Order approved by purchasing officer on Aug 9th Design of new tank finished

- Slit and FC as they are- If approved by all concerned people

- Launch tank fabrication Delays

- From Pantechnik offer: 5 month (Aug. Excluded) - Need to follow up to ensure reception and installation for ~Feb2014

Costs- 90kEu - Tank costs to be estimated

Operation&Control- It is not foreseen to integrate the system into the CO infrastructure- System to be used on stand-alone PC (control + data processing via Labview provided by

Pantechnik) ‘VIA fellow’ (shared by ABP and BI), from end of 2013, supposed to look also

into emittance measurements at Linac3

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