Holger Kollmus - VBE-UHV 1

SIS100_1 ERDA Measurements

ERDA – Measurements: Understanding of

Ion Beam-Loss Induced Desorption

Holger Kollmus - VBE-UHV 2

Prospects

elemet specific depth profiling of samples by detection of elastically scattered recoil ions

surface - bulk information

characterization of sample properties and

possible modification under ion irradiation

time resolved monitoring of sample evolution

in situ cleaning of target using Xe-sputter gun

access to physics of ion induced desorption

Ion beam loss induced desorption is a serious luminosity limitation for SIS18

Holger Kollmus - VBE-UHV 3

Work Plan

1st quarter 2nd quarter 3rd quarter 4th quarter 1st quarter 2nd quarter 2nd half 1st half 2nd half

Task1:

ERDA measurements

Set- up of ERDA experiment at HLI of GSI, first experiments with different stainless steel targetsExperiments with pumping surfaces (NEG, Pd, Ti,...), Implementation of energy dispersive electron detectorExperiments with layered targets, diffusion barriers, measurements on electronic desorption yields

ERDA as standard tool for quality control

2005 2006 2007

Holger Kollmus - VBE-UHV 4

Milestones and Deliverables

Milestones:

01-Jun-2005 Influence of oxide layer on stainless steel determined02-Jan-2006 Desorption rates of activated and saturated getter materials measured02-Jan-2007 Decision on adequate chamber and/or collimator material and in situ

cleaning methodes

Deliverables:

01-Jun-2005 Report on the influence of the oxide layer on the desorption yieldof stainless steel targets

01-Jan-2006 Summary result of ERD Analysis of pumping and saturated surfaces31-Dec-2007 Selection of adequate chamber and collimator materials based on

ERDA measurements

Holger Kollmus - VBE-UHV 5

Status of ERDA-Experiment 01-2006 (a)

Residual GasAnalyser

Detector

Xe Sputter Gun

Beam

Target HolderFeedthrough

Faraday Cup

•

static vacuum 10-11 mbar, only UHV-ERDA worldwide

Holger Kollmus - VBE-UHV 6

Status of ERDA-Experiment 01-2006 (b)

beam times Ca10+ (III/2005): commissioning, desorption of silicon, influence of

surface contaminations Xe18+ (III/2005): influence of oxide layer on stainless steel today Xe18+: desorption of high purity copper, influence of oxide

layer, desorption of gold terminated copper, secondary electron emission

NiFeCr

Si

ONC

Holger Kollmus - VBE-UHV 7

ERDA Results Silicon

clear correlation between desorption yield and target modification clean Si in UHV no desorption, only sputtering

0 2000 4000 6000 800010-13

10-12

10-11

3x10-9

4x10-9

5x10-9

pre

ssu

re

tota

l[m

bar

]pa

rtia

l[A

]

time [s]

2 12 14 15 28 29 32 44 total

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ERDA Results Stainless Steel

clear correlation between oxide layer and desorption desorption can be only reduced to the bulk contamination level

Holger Kollmus - VBE-UHV 9

ERDA New Time Schedule

Nr. Task 1 2 3 4 1 2 3 4 1 2 3 4

1 ERDA Measurements                        

2 Set-up of UHV-ERDA at the HLI, Commissioning    

3Measurements with stainless steel targets and silicon      

influence of oxide layer      

4Measurements with Copper and Gold coated Copper    

   

5 Desorption yield contribution of        

secondary electrons        

6 Desorption yield of pump. and satur. surfaces          

         

7 Exp. with layered targets, diff. barriers    

   

8Desc. on adequate chamber and or collimator material    

   

Holger Kollmus - VBE-UHV 10

ERDA Milestones

today we can report on: influence of surface contamination of silicon wafer influence of oxide layer on stainless steel (preliminary)

soon we can report on: desorption yield of OFHC copper, influence of oxide layer on

copper desorption yield of gold coated copper first test on the influence of secondary electron emission

we are slightly out of the time schedule, but we have reasonable progresswe have slightly changed the scientific program due to recent results

Holger Kollmus - VBE-UHV 11

First Publication – GSI Scientific Report

Holger Kollmus - VBE-UHV 12

Personal an Financial Situation

EU OC EU OC EU OCplanned (PM) 18 43.2 0 2.2 0 18presently spent (PM) 0 17 0 0.7 0 0investment (€) 30.0

0068.10

08.300 0 5.00

00

presently spent (€) 60.000 2.800 0

GSI LMU TUD