research article emittance measurement for beamline ...4 2 024 x (a) film data twiss parameter for...

Research ArticleEmittance Measurement for Beamline Extension atthe PET Cyclotron

Sae-Hoon Park Sang-Hoon Lee and Yu-Seok Kim

Department of Energy amp Environment Engineering Dongguk University Gyeongju Campus Seokjang-dongGyeongju-si Gyeongsangbuk-do 38066 Republic of Korea

Correspondence should be addressed to Yu-Seok Kim unisondonggukackr

Received 29 November 2015 Accepted 3 March 2016

Academic Editor Keith E Holbert

Copyright copy 2016 Sae-Hoon Park et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Particle-induced X-ray emission is used for determining the elemental composition of materials This method uses low-energyprotons (of several MeV) which can be obtained from high-energy (of tens MeV) accelerators Instead of manufacturing anaccelerator for generating the MeV protons the use of a PET cyclotron has been suggested for designing the beamline formultipurpose applications especially for the PIXE experiment which has a dedicated high-energy (of tens MeV) accelerator Thebeam properties of the cyclotron were determined at this experimental facility by using an external beamline before transferring theion beam to the experimental chamber We measured the beam profile and calculated the emittance using the pepper-pot methodThe beam profile was measured as the beam current using a wire scanner and the emittance was measured as the beam distributionat the beam dump using a radiochromic film We analyzed the measurement results and are planning to use the results obtained inthe simulations of external beamline and aligned beamline components We will consider energy degradation after computing thebeamline simulationThe experimental study focused on measuring the emittance from the cyclotron and the results of this studyare presented in this paper

1 Introduction

Particle-induced X-ray emission is a nondestructive tech-nique used for determining the elemental composition ofmaterials or samples This method has been applied in manydifferent fields using low-energy protons (1ndash5MeV) protonswith this energy can be generated atMeV accelerator facilities[1] PET cyclotrons (of 13MeV) have been proposed forproviding a beam of protons with energy of several MeVfor designing the beamline for multipurpose applicationsTo extend their applicability the cyclotrons can be utilizedfor analytical techniques that use MeV ion beams withenergy attenuationThe PIXE beamline consists of one dipolemagnet one quadrupole doublet and one quadrupole tripletThese magnets are used for focusing the beam to the PIXEchamber with linear dimension of about 1mmThe beam sizeshould be adjusted from 1 to 10mm and the beam currentof 50 nA should be obtained at the PIXE beamline targetchamber

The PIXE beamline from the cyclotron is projected to thetarget point in a target chamber in the experimental roomThe emittance of a PET cyclotron has not been measured atthe latter part of cyclotron targetThebeamprofile has alreadybeen measured and the beam size and the divergence wereshown to be linearly related [2] However to extract the exter-nal beamline we measured the beam profile and the emit-tance by using a diagnostic device employing a more precisemeasurement method For the external beamline the beamprofile and the emittance were measured and calculated andthe results will be simulated and aligned with the beamlinecomponents To measure properties of the cyclotron beamwe have to consider the external beamline for the PIXEexperiment This experimental paper focused on measuringthe emittance of protons from the PET cyclotron Theexperiment was performed at the CRC (Cyclotron ResearchCenter) installed in Chosun University South Korea

Measuring the beam emittance at a PET cyclotron beam-line is of fundamental importance The traditional method

Hindawi Publishing CorporationScience and Technology of Nuclear InstallationsVolume 2016 Article ID 4697247 4 pageshttpdxdoiorg10115520164697247

2 Science and Technology of Nuclear Installations

Beam profile in X-axis

X-axis

Beam

curr

ent (

nA)

0

1

2

3

4

5

0 5 10 15 20 25 30 35minus5Position (mm)

(a)

Beam profile in Y-axis

Y-axis

00

05

10

15

20

25

30

35

Beam

curr

ent (

nA)


(b)

Figure 1 Beam profile at the cyclotron target part (a) 119909-axis view and (b) 119910-axis view

Slit or pepper-potplate Beam profile

Incidentbeam

x X

L

Figure 2 Experimental setup for emittance measurement 119871 is thedistance between the pepper-pot plate and the beam dump with theradiochromic film

for measuring the beam profile as a function of the strengthof a focusing element is not applicable and only the slitand pepper-pot techniques can be used [3] Two commonlyused emittance measurement methods are the method ofslits and the pepper-pot method The former employs a one-dimensional emittance measurement device and the latteremploys a two-dimensional one [4] In our experiments apepper-pot plate was installed at the cyclotron target Thewire scanner measured the beam current of the beam profileat the cyclotron target The beam profile at the cyclotrontarget was measured by using the NI Labview software andequipment for controlling the motor and data acquisition forthe beam current The radiochromic film at the beam dumpwas also calculated by using Matlab for calculating the rmsemittance

2 Materials and Methods

A beam of particles can be characterized in detail by usingits density in the six-dimensional phase space [5] Beamemittance is one of the beam properties for particle acceler-ators Several methods have been developed for measuringthe beam emittance such as the slit [6] pepper-pot [78] and quad scan methods [9] We used the pepper-potmethod for the direct measurement of three-dimensionalbeam emittance The beam profile of the initial beam at thetarget was acquired using the wire scanner [10] and theresults are shown in Figure 1 In the case of the pepper-potmethod we analyzed the radiochromic film by using Matlab

Themethod of slits employs a one-dimensional emittancemeasurement device while the pepper-pot method employsa two-dimensional one [11] The setup for the measurementbased on the pepper-pot method is shown in Figure 2 Theexperimental setup consisted of a 2mm thick pepper-potplate comprised of carbon that was located at the cyclotrontarget The thickness of the pepper-pot plate was set to 2mmconsidering the stopping depth of 13MeV protons The wirescanner was installed behind the pepper-pot plate The wirescanner allowed measuring the beam profile of the beamthat was incident on the scanner In film measurements thedistance between the pepper-pot plate and the radiochromicfilm (GAFCHROMIC film HD-810 for high density) was2095mm

The incident beam arrived from the cyclotron and pen-etrated through the pepper-pot plate The pepper-pot platecoordinate was designated as 119909 while that of the beamprofile was designated by 119883 The beam size at the pepper-pot plate was determined considering the dimensions ofthe slit appearance the thickness of the pepper-pot plateand the distance between the pepper-pot plate and the

Science and Technology of Nuclear Installations 3Y

-axi

s (pi

xel)

X-axis (pixel)

400

600

800

1000

200

1200

400 600 800 1000200 1200

Figure 3 Film contour map obtained using Matlab

radiochromic film The beam distribution was fitted usingGaussian functions for all profile peaks

In the film experiment the measurement was performedby mounting the radiochromic film on the beam dump Thehole diameters in the pepper-pot plate were 1mm and thedistance between adjacent holes was 2mm The pepper-potplate was 2mm thick and had 25 holes Beam irradiation timewas 5 seconds and the beam current at the target was 013120583ALonger irradiation times could result in film damage therebydestroying the image Filmmeasurementwas performedwithshort irradiation time for reducing the film image error Thefilm analysis was performed using Matlab

3 Results and Discussion

The film intensity data were encoded as double precisionnumbers In turn these data were converted to the RGBformat with brightness ranging from 0 to 1 The film imageresolution was 600 dots per inch (DPI) and the image sizewas 1392 times 1392 pixels The size of one pixel was 4233 120583mThe contour map was created using the film data in the RGBformat and is shown in Figure 3

The film data were divided into rows (119909) and columns(119910) The sum of all values in a certain row represents theemittance along the 119910 axis and the sum of all values in acertain column represents the emittance along the 119909 axisAll rows and columns exhibited five peaks that were fittedwith Gaussian functions in Matlab Three parametersmdashtheintensity peak position and peak sigmamdashwere computedfrom these Gaussian fits of the film data The emittance wascalculated as [12]

120598 = radic⟨1199092⟩ ⟨11990910158402⟩ minus ⟨119909119909

1015840⟩2

(1)

The rms emittance was calculated from the Gaussianfits in Matlab for both 119909- and 119910-directions The rms emit-tance values were 40401120587mmmrad for the 119909-direction and47431120587mmmrad for the 119910-direction We also computed thebeam twiss parameters from the calculated values of rms

Film dataTwiss parameter for emittance ellipse

Phase space in X-axis

minus0010

minus0005

0000

0005

0010

X998400

0 2 4minus2minus4X

(a)


Phase space in Y-axis

minus0015

minus0010

minus0005

0000

0005

0010

0015Y998400

20 4 6minus4 minus2minus6Y

(b)

Figure 4 Phase space ellipse (a) 119883-coordinate and (b) 119884-coordinate

emittance These values determine the shape and orientationof the beam ellipse in the phase space [13] The phase spaceellipses are shown in Figure 4 The red dots delimit themaximal area in the phase space [14] while the black dotsenclosed in the red dots are the film data These results willbe used to estimate the beamline simulations

4 Conclusions

The CRC has been proposed to be used for producing anexternal beamline for experimental research To use theexisting facility for producing PET cyclotron protons as anexternal beamline the beam energy should be reduced toseveral MeVThere is no correlation between beam emittance


and energy degradation at the end of beamline To generatean external beamline experiments were conducted using thespecific data of beam emittance at the latter part of cyclotrontarget by a more precise measurement method The beamsize was measured with the wire scanner The rms emittancewas calculated from the Gaussian fits parameters and phasespace ellipse The beam emittance was measured for provid-ing conditioning parameters for design and simulations ofbeamline components of the external beamline for obtainingthe desired beam shape

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

This research was supported by the National Nuclear RampDProgram through theNational Research Foundation of Korea(NRF) funded by the Ministry of Science ICT and FuturePlanning (2015M2B2A6030404) The authors would liketo express their deepest gratitude to the CRC of ChosunUniversity for their help in conducting the experiment

References

[1] K Ishii and SMorita ldquoTheoretical estimation of PIXEdetectionlimitsrdquo Nuclear Instruments and Methods in Physics ResearchSection B Beam Interactions with Materials and Atoms vol 34no 2 pp 209ndash216 1988

[2] S-H Park and Y-S Kim ldquoCharacterization of the beam profilefor the PIXEPIGE beam line at the CRC proton cyclotronrdquoJournal of the Korean Physical Society vol 63 no 7 pp 1291ndash1295 2013

[3] C H Wang M Zhang M Clausen and Z Kakucs ldquoSlitsmeasurement of emittance on TTFrdquo in Proceedings of the 7thInternational Conference on Accelerator and Large ExperimentalPhysics Control Systems Trieste Italy October 1999

[4] M Zhang ldquoEmittance formula for slits and pepper-pot mea-surementrdquo Tech Rep FERMILAB-TM-1998 Fermi NationalAccelerator Laboratory Batavia Ill USA 1998

[5] K T McDonald and D P Russell Methods of Emittance Mea-surement Joseph Henry Laboratories Princeton UniversityPrinceton NJ USA 1988

[6] C Liu D Gassner M Minty and P Thieberger Multi-SlitBased Emittance Measurement Study for BNL ERL Collider-Accelerator Department Brookhaven National LaboratoryUpton NY USA 2012

[7] H Takeda and J H Billen ldquoPARMILArdquo Los Alamos NationalLaboratory Report LA-UR-98-4478 Los Alamos National Lab-oratory Los Alamos NM USA 2004

[8] S Y Lee Accelerator Physics World Scientific Publishing Com-pany New York NY USA 2nd edition 2004

[9] J G Wang D X Wang and M Reiser ldquoBeam emittancemeasurement by the pepper-pot methodrdquo Nuclear InstrumentsandMethods in Physics Research A vol 307 no 2-3 pp 190ndash1941991

[10] P N Ostroumov P Billquist M Portillo and W Q ShenldquoDesign and test of a beam profile monitoring device for low

intensity radioactive beamsrdquo Review of Scientific Instrumentsvol 73 no 1 p 56 2002

[11] R Hollinger K Volk and H Klein ldquoMeasurement of the beamemittance of the Frankfurt proton sourcerdquo Review of ScientificInstruments vol 73 no 2 p 1027 2002

[12] T P Wangler RF Linear Accelerators John Wiley amp Sons NewYork NY USA 2nd edition 1998

[13] N Tongnopparat L D Yu T Vilaithong and H WiedemannldquoIon beam emittance measurement based on transformationmatrix theoryrdquo Journal of the Korean Physical Society vol 53no 6 pp 3744ndash3748 2008

[14] S Kondrashev A Barcikowski B Mustapha P N Ostroumovand N Vinogradov ldquoDevelopment of a pepper pot emittanceprobe and its application for ECR ion beam studiesrdquo NuclearInstruments and Methods in Physics Research Section A Accel-erators Spectrometers Detectors and Associated Equipment vol606 no 3 pp 296ndash304 2009

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Beam profile in X-axis

X-axis

Beam

curr

ent (

nA)

0

1

2

3

4

5


(a)

Beam profile in Y-axis

Y-axis

00

05

10

15

20

25

30

35

Beam

curr

ent (

nA)


(b)

Figure 1 Beam profile at the cyclotron target part (a) 119909-axis view and (b) 119910-axis view

Slit or pepper-potplate Beam profile

Incidentbeam

x X

L

Figure 2 Experimental setup for emittance measurement 119871 is thedistance between the pepper-pot plate and the beam dump with theradiochromic film

for measuring the beam profile as a function of the strengthof a focusing element is not applicable and only the slitand pepper-pot techniques can be used [3] Two commonlyused emittance measurement methods are the method ofslits and the pepper-pot method The former employs a one-dimensional emittance measurement device and the latteremploys a two-dimensional one [4] In our experiments apepper-pot plate was installed at the cyclotron target Thewire scanner measured the beam current of the beam profileat the cyclotron target The beam profile at the cyclotrontarget was measured by using the NI Labview software andequipment for controlling the motor and data acquisition forthe beam current The radiochromic film at the beam dumpwas also calculated by using Matlab for calculating the rmsemittance

2 Materials and Methods

A beam of particles can be characterized in detail by usingits density in the six-dimensional phase space [5] Beamemittance is one of the beam properties for particle acceler-ators Several methods have been developed for measuringthe beam emittance such as the slit [6] pepper-pot [78] and quad scan methods [9] We used the pepper-potmethod for the direct measurement of three-dimensionalbeam emittance The beam profile of the initial beam at thetarget was acquired using the wire scanner [10] and theresults are shown in Figure 1 In the case of the pepper-potmethod we analyzed the radiochromic film by using Matlab

Themethod of slits employs a one-dimensional emittancemeasurement device while the pepper-pot method employsa two-dimensional one [11] The setup for the measurementbased on the pepper-pot method is shown in Figure 2 Theexperimental setup consisted of a 2mm thick pepper-potplate comprised of carbon that was located at the cyclotrontarget The thickness of the pepper-pot plate was set to 2mmconsidering the stopping depth of 13MeV protons The wirescanner was installed behind the pepper-pot plate The wirescanner allowed measuring the beam profile of the beamthat was incident on the scanner In film measurements thedistance between the pepper-pot plate and the radiochromicfilm (GAFCHROMIC film HD-810 for high density) was2095mm

The incident beam arrived from the cyclotron and pen-etrated through the pepper-pot plate The pepper-pot platecoordinate was designated as 119909 while that of the beamprofile was designated by 119883 The beam size at the pepper-pot plate was determined considering the dimensions ofthe slit appearance the thickness of the pepper-pot plateand the distance between the pepper-pot plate and the


-axi

s (pi

xel)

X-axis (pixel)

400

600

800

1000

200

1200

400 600 800 1000200 1200







120598 = radic⟨1199092⟩ ⟨11990910158402⟩ minus ⟨119909119909

1015840⟩2

(1)




minus0010

minus0005

0000

0005

0010

X998400

0 2 4minus2minus4X

(a)



minus0015

minus0010

minus0005

0000

0005

0010

0015Y998400


(b)



4 Conclusions




Competing Interests


Acknowledgments


References




















FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















-axi

s (pi

xel)

X-axis (pixel)

400

600

800

1000

200

1200

400 600 800 1000200 1200







120598 = radic⟨1199092⟩ ⟨11990910158402⟩ minus ⟨119909119909

1015840⟩2

(1)




minus0010

minus0005

0000

0005

0010

X998400

0 2 4minus2minus4X

(a)



minus0015

minus0010

minus0005

0000

0005

0010

0015Y998400


(b)



4 Conclusions




Competing Interests


Acknowledgments


References




















FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of



















Competing Interests


Acknowledgments


References




















FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of





















FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of

















research article emittance measurement for beamline ...4 2 024 x (a) film data twiss parameter for...

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