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A cerium fluoride scintillator coupled to a FEU-140 photomultiplier
Nuclear Instruments and Methods in Nonh4h%nd
Physics
Research A322 (1992) 302-303 Seebon A
tWr to the Editor
ceri
e scintillator c
t®
led to a FEU-140
lti lier
ozma ", Sergei Afanasiev, Alexander alakhov and Anatoli Povtoreiko Lahorazoyy of H~gh Enej ;gies, JIVR Dubna, P.O. Bar M Md M Mv Ahmwn% &Mn WknUM eter
ReL,-ived 15 June 1992 A large CeF~,, scintillation crystal coupled to a FEU-140 PMT was tested with gamma-ray sources. A good energy resolution as %xell as uniformity of the light output along the length of the crystal are demonstrated . In the framework of the experimental project SPHERE [1] realized at the Laboratory of High Energies of the JINR Dubna, we continue to investigate the properties of the most prospective scintillation crystals 121 for possible use in high performance electromagnetic calorimeters . Recently, we have started to test the scintillation characteristics of CeF,,. In the first step of investigation . we have tested our Cef~, samples with gamma-ray sources. Further, we will proceed tests with beams- of relativistic particles accelerated at the Dubna ~-nchrophasolron and we will also investigate the radiation hardness of CeF, as well . The attractive properties of CeF, as a scintillator for high-rate applications were discovered by Anderson [3]. CeF., has a high density (6.16 g/cm 3) and short radiation length (1 .68 cm). Like BaF., it has two emission components with decay times of about 5 ns (at 300 nm) and 30 ns (at 340 nm). The light output of CeF, is about 501-r' that of BGO. A timing resolution for a single CeF., PET crystal of 0 .56 ns was achieved [4]. A practical advantage of CS F; is its chemical and mechanical stability. Our test measurements have been performed with a CeF3 crystal of rectangular shape and dimensions 3 X 3 X 6 cm' coupled to the 2.8 cm diameter window of a quartz-window FEU-140 photomultiplier [5] having a good response in the appropriate wavelength region (see fig. 1) . The sides of the crystal were wrapped with reflective Teflon tape of thickness about I mm . The photomultiplier was operated at -1 .9 M The standard voltage divider chain as well as appropriate electronics were used .
This work has been carried out in the frame of the Crystal Clear Collaboration, CERN R&D Project RD-18 [2]. Spokesman of the Czech Group in tht CERN Crystal Clear Collaboration.
WAVELENGTH [--]
Fig. 1 . Spectral sensitivity characteristic of FEU-140 PMT. The energy resolution (FWHM) has been determined in the energy range 0.662-4 .440 MeV using the following gamma-ray sources: ' 37CS, `'"Co, "Y, 22 `1h and 24 'Am + Be . The results are summarized in table 1. As an example, the energy spectrum measured with a "'Co gamnia-ray source (1 .173 MeV and 1 .334 MeV) Table I Energy resolution (FWHM) for a 3 X 3 X 6 cm ; CeF, crystal Gamma-ray source 137cs "Y Mco Mc o 88Y
228 Th
24 'Am
+ Be
0168A(M2/92/$05MO 0 1992 - Elievier Science Publishers B.V . All rights rcscrved
Energy [MeV] 0.662 0.898 1 .173 1 .334 1 .836 2 .614 4.440
FWHM I rcI 17 .6 15 .0 13 .2 12 .4 10.6 8 .9 7.2
P. Kozina et A / CeF.? scintillator coupled to a FE-U-140 photontultiplier
C
300 280
CD b-
260
CD 66
240
Cà.
8
.
3V03
--Y-
1
662 heV
137
Cs
0
220 1
2
3
SOURCE POSITIO CHANNEL
Fig . 2 . Pulse-height spectrum of the .1 X 3 X 6 cm ; CeF~j scintillator irradiated with 611CO gamma-ray source . is displayed in fig. 2 . The results of measurements of energy resolution in the energy range between 662 keV and 4 .44 MeV proved that the FWHM - I/ VE is a good approximation (see fig. 3) .
4
5
6
Fig. 4. Peak position of a " QCs spectrum as a function of source position from the PMT.
We have also tested the uniformity of response of the scintillator. The pulse-height spectra of the crystal, irradiated with a collimated "'Cs gamma-ray source at different positions along the long side of a crystal were measured . The results are displayed in fig . 4, where the position of an appropriate peak as a function of source position is shown . A slight nonuniformity at the top and the end sides of the crystal was found .
References
0
10
20
FWHN [%]
Fig . 3 . 1 IFE dependence of the FWHM .
[1] A . Malakhov, Proc. XII Int . Conf. on Particles and Nuclei, PANIC XII, Cambridge, 1990, ed . T.W. Donnelly, contributed paper, X-26. [2] Crystal Clear Collaboration, CERN/DRDC Status Report 92-02 (1992). [3] D .F. Anderson, Fermilab-Pub-89/169 (1989) . [4] D .F. Anderson, IEEE Trans. Nucl . Sci . NS-36 (1989) 137. [5] P . Kozma, S.V . Afanasiev, A .I . Malakhov, P . Schotanus and P . Dorenbos, Nucl. Insu. and Will, . A314 (1992) 26.
Physics
Research A322 (1992) 302-303 Seebon A
tWr to the Editor
ceri
e scintillator c
t®
led to a FEU-140
lti lier
ozma ", Sergei Afanasiev, Alexander alakhov and Anatoli Povtoreiko Lahorazoyy of H~gh Enej ;gies, JIVR Dubna, P.O. Bar M Md M Mv Ahmwn% &Mn WknUM eter
ReL,-ived 15 June 1992 A large CeF~,, scintillation crystal coupled to a FEU-140 PMT was tested with gamma-ray sources. A good energy resolution as %xell as uniformity of the light output along the length of the crystal are demonstrated . In the framework of the experimental project SPHERE [1] realized at the Laboratory of High Energies of the JINR Dubna, we continue to investigate the properties of the most prospective scintillation crystals 121 for possible use in high performance electromagnetic calorimeters . Recently, we have started to test the scintillation characteristics of CeF,,. In the first step of investigation . we have tested our Cef~, samples with gamma-ray sources. Further, we will proceed tests with beams- of relativistic particles accelerated at the Dubna ~-nchrophasolron and we will also investigate the radiation hardness of CeF, as well . The attractive properties of CeF, as a scintillator for high-rate applications were discovered by Anderson [3]. CeF., has a high density (6.16 g/cm 3) and short radiation length (1 .68 cm). Like BaF., it has two emission components with decay times of about 5 ns (at 300 nm) and 30 ns (at 340 nm). The light output of CeF, is about 501-r' that of BGO. A timing resolution for a single CeF., PET crystal of 0 .56 ns was achieved [4]. A practical advantage of CS F; is its chemical and mechanical stability. Our test measurements have been performed with a CeF3 crystal of rectangular shape and dimensions 3 X 3 X 6 cm' coupled to the 2.8 cm diameter window of a quartz-window FEU-140 photomultiplier [5] having a good response in the appropriate wavelength region (see fig. 1) . The sides of the crystal were wrapped with reflective Teflon tape of thickness about I mm . The photomultiplier was operated at -1 .9 M The standard voltage divider chain as well as appropriate electronics were used .
This work has been carried out in the frame of the Crystal Clear Collaboration, CERN R&D Project RD-18 [2]. Spokesman of the Czech Group in tht CERN Crystal Clear Collaboration.
WAVELENGTH [--]
Fig. 1 . Spectral sensitivity characteristic of FEU-140 PMT. The energy resolution (FWHM) has been determined in the energy range 0.662-4 .440 MeV using the following gamma-ray sources: ' 37CS, `'"Co, "Y, 22 `1h and 24 'Am + Be . The results are summarized in table 1. As an example, the energy spectrum measured with a "'Co gamnia-ray source (1 .173 MeV and 1 .334 MeV) Table I Energy resolution (FWHM) for a 3 X 3 X 6 cm ; CeF, crystal Gamma-ray source 137cs "Y Mco Mc o 88Y
228 Th
24 'Am
+ Be
0168A(M2/92/$05MO 0 1992 - Elievier Science Publishers B.V . All rights rcscrved
Energy [MeV] 0.662 0.898 1 .173 1 .334 1 .836 2 .614 4.440
FWHM I rcI 17 .6 15 .0 13 .2 12 .4 10.6 8 .9 7.2
P. Kozina et A / CeF.? scintillator coupled to a FE-U-140 photontultiplier
C
300 280
CD b-
260
CD 66
240
Cà.
8
.
3V03
--Y-
1
662 heV
137
Cs
0
220 1
2
3
SOURCE POSITIO CHANNEL
Fig . 2 . Pulse-height spectrum of the .1 X 3 X 6 cm ; CeF~j scintillator irradiated with 611CO gamma-ray source . is displayed in fig. 2 . The results of measurements of energy resolution in the energy range between 662 keV and 4 .44 MeV proved that the FWHM - I/ VE is a good approximation (see fig. 3) .
4
5
6
Fig. 4. Peak position of a " QCs spectrum as a function of source position from the PMT.
We have also tested the uniformity of response of the scintillator. The pulse-height spectra of the crystal, irradiated with a collimated "'Cs gamma-ray source at different positions along the long side of a crystal were measured . The results are displayed in fig . 4, where the position of an appropriate peak as a function of source position is shown . A slight nonuniformity at the top and the end sides of the crystal was found .
References
0
10
20
FWHN [%]
Fig . 3 . 1 IFE dependence of the FWHM .
[1] A . Malakhov, Proc. XII Int . Conf. on Particles and Nuclei, PANIC XII, Cambridge, 1990, ed . T.W. Donnelly, contributed paper, X-26. [2] Crystal Clear Collaboration, CERN/DRDC Status Report 92-02 (1992). [3] D .F. Anderson, Fermilab-Pub-89/169 (1989) . [4] D .F. Anderson, IEEE Trans. Nucl . Sci . NS-36 (1989) 137. [5] P . Kozma, S.V . Afanasiev, A .I . Malakhov, P . Schotanus and P . Dorenbos, Nucl. Insu. and Will, . A314 (1992) 26.