- 9 th Sep. 2009 - Introduction Gas-Jet Simulations Experimental Setup Massimiliano Putignano...

- 9- 9thth Sep. 2009 - Sep. 2009 - Introduction Gas-Jet Simulations Experimental Setup

Massimiliano PutignanoMassimiliano Putignano

Development of a Beam Profile Monitor Based Development of a Beam Profile Monitor Based on a Supersonic Gas-Jet Curtainon a Supersonic Gas-Jet Curtain

GSI Talk, DarmstadtGSI Talk, Darmstadt

Website:Website: www.quasar-group.orgwww.quasar-group.orgEmail:Email: [email protected] [email protected]

Massimiliano Putignano Massimiliano Putignano - 9- 9thth Sep 2009 - Sep 2009 - Slide Slide 22/9/9

Introduction Gas-Jet Simulations Experimental Setup

a Beam Profile Monitor using a Gas Jet?a Beam Profile Monitor using a Gas Jet?

• USR Project at FLAIR (FAIR facility, Darmstadt)

- Ultra-low energy pbars (20-300

keV)- Coasting/bunched beam- Low pressure

(10-11 mbar)• Low perturbation AND high count rate• Investigation of

the Gas-Jet

A. Papash and C. P. Welsch, Physics of

Particles and Nuclei Letters, Vol.

6, No. 3. (2009), pp. 216-226.

• Inclusion in the Reaction Microscope

Reaction Rate (events/s)

0

1

2

3

4

5

6

7

-10 -9 -8 -7 -6 -5 -4

Log. Pressure at 300 K (mbar)

Log.

Rea

ctio

n R

ate

(eve

nts/

s)

1 mm2 mm5 mm

Log. PressureLog.

Rea

ctio

n Ra

te

WhyWhy



does it work?does it work?HowHow



do we start?do we start?

State-of-the-artState-of-the-art• Detailed study of expansion structure• Assessment of the impact on jet parameters• Optimization of axis-symmetric jet for use as a

target.

All optimization studies performed for an axis-symmetric jet.

• IdentifyIdentify parametersparameters of interest to diagnostics.of interest to diagnostics.• Propose a Propose a novel nozzle-skimmer systemnovel nozzle-skimmer system..• Extend existing studiesExtend existing studies to planar jets.to planar jets.

M.Jugroot M.Jugroot et alet al: : Numerical investigation of Numerical investigation of interface region flows in mass spectrometers: interface region flows in mass spectrometers: neutral gas transportneutral gas transport – J. Phys. D: Applied – J. Phys. D: Applied Physics, vol. 37 (2004) pp 1289.Physics, vol. 37 (2004) pp 1289.

WhereWhere



Jet structure calculationsJet structure calculations

• Governing equations– Continuity Equation

• A statement of conservation of mass

– Energy Equation• Resulting from neglecting thermal and viscous effects

– Momentum Equation (Euler’s Equation)• A statement of conservation of momentum

– Equation of State• Ideal gas equation of state (from kinetic theory)

– Thermal Equation of state• Definition of int. energy and measurement of specific heat.



variables and observables do we choose?variables and observables do we choose?

-2 dB Attenuation

SSWW

SDSD

DisDistt.

– angle of skimmer aperture in the direction of curtain expansion; – angle of skimmer aperture in the direction perpendicular to curtain expansionSWSW – skimmer slit widthSDSD – skimmer depthDistDist – nozzle-skimmer distance

MMmaxmax – Maximum Mach NumberCMCMmax max – Coordinates maximum MMMmax70%max70% - Maximum M at 70% simulation domain distance from nozzleWW – Curtain width (at -2 dB attenuation); DD – Curtain depth (at -2dB attenuation);

WhichWhich



WhatWhat do we find? do we find?

Curtain behavioral trendsCurtain behavioral trends



Simulations outputSimulations output

• System can be optimized through nozzle-skimmer geometry.

• Slit nozzle (instead of circular nozzle)• Nozzle and skimmer slits have to be perpendicular• Shaping of the gas curtain is feasible.Actual value of quality ratio: W/D.

Decreases of a factor of 2-32-3 moving from Slit nozzle to Circular nozzle.Homogeneity of curtain: / =Nozzle-Skimmer system:

Perpendicular Parallel 89% 68%89% 68% -2 dB

Attenuation



and now?and now?

• Differential Pumping• Longitudinal (20 mm (20 mm range) range) and angular (5(5o o range)range) fine tuning.

ow!ow!WW……



WhoWho do I thank? do I thank?

• Acknowledgements:– Kai-Uwe KühnelKai-Uwe Kühnel– Angela IntermiteAngela Intermite– Carsten P. WelschCarsten P. Welsch

• References:1.1. M.Putignano M.Putignano et alet al: : A Fast, Low Perturbation Ionization Beam Profile Monitor Based on a A Fast, Low Perturbation Ionization Beam Profile Monitor Based on a

Gas-jet Curtain for the Ultra Low Energy Storage RingGas-jet Curtain for the Ultra Low Energy Storage Ring - Hyperfine Interaction, accepted. - Hyperfine Interaction, accepted.2.2. M.Putignano M.Putignano et alet al: : Design of a nozzle-skimmer system for a low perturbation ionization Design of a nozzle-skimmer system for a low perturbation ionization

beam profile monitorbeam profile monitor – DIPAC09 Proceedings. – DIPAC09 Proceedings.3.3. M.Jugroot M.Jugroot et alet al: : Numerical investigation of interface region flows in mass spectrometers: Numerical investigation of interface region flows in mass spectrometers:

neutral gas transportneutral gas transport – J. Phys. D: Applied Physics, vol. 37 (2004) pp 1289. – J. Phys. D: Applied Physics, vol. 37 (2004) pp 1289.4.4. Y. Hashimoto Y. Hashimoto et alet al: : Oxygen gas-sheet beam profile monitor for the synchrotron and Oxygen gas-sheet beam profile monitor for the synchrotron and

storage ringstorage ring - Nucl. - Nucl. Instr. Meth. Phys. Res. A 527 (2004) 289.Instr. Meth. Phys. Res. A 527 (2004) 289.

Thank you for your attentionThank you for your attention

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