- Email: [email protected]
The white SR spectrum experimental station
Nuclear Instruments and Methods in Physics Research A 448 (2000) 126}128
The white SR spectrum experimental station A.I. Ancharov *, O.V. Evdokov , B.P. Tolochko , A.V. Sukhorukov , S.E. Baru, G.A. Savinov, A.V. Kosov, M.A. Sheromov, S.K. Sikka, S.N. Momin Institute of Solid State Chemistry and Mechanochemistry, Kutateladze str. 18, 630218 Novosibirsk, Russia Budker Institute of Nuclear Physics, Novosibirsk, Russia Bhabha Atomic Research Center, Bombay India
Abstract A new experimental station for working with white synchrotron radiation is described. Radiation from the bending magnet of the VEPP-4 storage ring is used. The station is destined for study of structures at high pressure by energy-dispersive and Laue di!raction methods. 2000 Elsevier Science B.V. All rights reserved. PACS: 07.35#k; 07.85.Oe; 61.10.Nz Keywords: Synchrotron radiation; Energy-dispersive di!raction; Laue di!raction; Instrumentation
One of the important features of synchrotron radiation is its high intensity in the wide spectrum range. `Whitea radiation is used in the energydispersive and Laue di!raction methods. Energydispersive di!raction is used in those cases where it is necessary to obtain structured information in a wide range of interplanar crystal spacings but it is impossible to design a sample cell with a wide window for the angle dispersive di!raction method. So, for investigations under high pressure, in conditions of hydrothermal synthesis and under some mechanical in#uence, the method of energy-dispersive di!raction is used. The method of Laue di!raction is used for studying a single crystal.
* Corresponding author. Tel.: #7-3832-394145; fax: #73832-342163, 7-3832-322847. E-mail address: [email protected] (A.I. Ancharov).
The new experimental station installed on SR beamline N7 of the VEPP-4 storage ring (Fig. 1) is intended for studies by these methods [1]. Development and construction of the station was realized within the framework of Indo-Russian Long-Term Program of cooperation in science and technology (ILTP). Three organizations participate in this project. They are Institute of Solid State Chemistry and Mechanochemistry, Budker Institute of Nuclear Physics (both in Novosibirsk, Russia) and Bhabha Atomic Research Center (Bombay, India). Beamline N7 receives radiation from magnet IV ("eld of 9.4560 kG). The critical energy and wavelength are 22.6 keV and 0.55 As , respectively. The X-ray beam passes from the storage ring in an evacuated beam pipe on the hutch. The beam pipe is divided into three sections. The "rst section has common vacuum with the storage ring and is separated from the next sections by four beryllium
0168-9002/00/$ - see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 0 0 ) 0 0 2 0 9 - 6
A.I. Ancharov et al. / Nuclear Instruments and Methods in Physics Research A 448 (2000) 126}128
Fig. 1. General view of station. On the right there are the collimator block and monochromator. The experimental hutch is on the left.
foils. Gaps between the foils are pumped by storage ring pumps. The next section has a foil, mounted in the entrance of the primary collimator block. Vacuum of this section is ensured by two magnetodischarge pumps, installed above the beam pipe. Three luminophor SR beam position monitors and three vacuum manometers are installed in the second section. The third channel section inputs radiation inside the experimental hutch. It ends with a beryllium foil 150 lm thick, installed on the #ange of the telescopic tube. Pumping-out of the third beamline section is produced by a vacuum pump with the liquid-nitrogen trap. Full thickness of the beryllium foils installed in the beamline is 1 mm. At a distance of 37 m from the point of radiating at the beginning of the third section a primary collimator is installed in the vacuum box 500;500;500 mm in size. The collimator consists of two vertical and two horizontal tantalum plates, installed on translation stages. An identical box is installed immediately behind the "rst box. It is intended for installation of a monochromator. Usage of a monochromator allows one to implement the scheme of precise energy-dispersive diffractometry. Experimental hutch (Fig. 2) is a vacuum-tight box made of 20 mm stainless steel with an internal size of 1100;870;680 mm. Two optical benches are installed in the box as a support for the
127
Fig. 2. Experimental hutch and two-coordinate detector DED-5.
equipment, including: (1) Ionization chamber for intensity monitoring of the primary beam, (2) Precision collimator with tantalum slits [2], (3) X}Z translation stage for collimator displacement, (4) High-pressure diamond anvil cell, (5) X}Z}H}u translation stage for the sample. Two types of detectors are used at stations: (1) liquid-nitrogen-cooled solid-state high-purity germanium detector `ORTECa is used in the energy-dispersive di!raction experiments; (2) two-coordinate detector `DED-5a is used in the Laue di!raction experiments. Both detectors are installed on the platform of the vertical translation stage. This mechanism gives a possibility for vertical movement of the detector up to 900 mm. One end of the platform is installed on a horizontal axis, which allows change of sloping of the detector from !53 to 303. Two types of output collimators can be used in the energy-dispersive di!raction method. The "rst type of collimator is a system of two tantalum slits with controlled size and position. The second type of collimator, made with a coniform slit, is installed near the semiconductor detector. The coniform slit allows collecting all radiation di!racted at a "xed angle. Use of a coniform slit raises system e$ciency,
SECTION IV.
128
A.I. Ancharov et al. / Nuclear Instruments and Methods in Physics Research A 448 (2000) 126}128
Fig. 3. Test Laue pattern obtained from a single crystal of quartz on the detector DED-5. (E"4.5 GeV, I"0 mA, time of exposition is 10 s.)
which is important for experiments with small amounts of material. Two-coordinate detector DED-5 was designed and made at Budker Institute of Nuclear Physics, Novosibirsk. This model [3] has two-coordinate multi-wired proportional chamber with an aperture 386;386 mm in size. The detector has 65536 channels 1.5;1.5 mm in size. The detector has two working modes: increment accumulation of data and the frame-by-frame mode. In the "rst regime, information on photon coordinates is stored in the special incremental memory. In the second mode, data are recorded to the memory (event by event); besides the coordinates, energy of photons and time of events are also recorded. Memory volume in the
frame-by-frame mode is 8 million events. The minimal frame time is about 100 ls. First test experiments on the station were conducted in April, 1998. Fig. 3 shows the Laue pattern from a single crystal of quartz.
References [1] A.I. Ancharov, B.P. Tolochko, R. Chidambaram et al., Nucl. Instr. and Meth. A 359 (1999) 206. [2] I.P. Dolbnya, N.G. Gavrilov, N.A. Mezentsev, V.F. Pindyurin. Rev. Sci. Instr. 63 (1992) 609. [3] V.M. Aulchenko, S.E. Baru, M.S. Dubrovin et al., J. Synch. Radial. 5 (1998) 263.
The white SR spectrum experimental station A.I. Ancharov *, O.V. Evdokov , B.P. Tolochko , A.V. Sukhorukov , S.E. Baru, G.A. Savinov, A.V. Kosov, M.A. Sheromov, S.K. Sikka, S.N. Momin Institute of Solid State Chemistry and Mechanochemistry, Kutateladze str. 18, 630218 Novosibirsk, Russia Budker Institute of Nuclear Physics, Novosibirsk, Russia Bhabha Atomic Research Center, Bombay India
Abstract A new experimental station for working with white synchrotron radiation is described. Radiation from the bending magnet of the VEPP-4 storage ring is used. The station is destined for study of structures at high pressure by energy-dispersive and Laue di!raction methods. 2000 Elsevier Science B.V. All rights reserved. PACS: 07.35#k; 07.85.Oe; 61.10.Nz Keywords: Synchrotron radiation; Energy-dispersive di!raction; Laue di!raction; Instrumentation
One of the important features of synchrotron radiation is its high intensity in the wide spectrum range. `Whitea radiation is used in the energydispersive and Laue di!raction methods. Energydispersive di!raction is used in those cases where it is necessary to obtain structured information in a wide range of interplanar crystal spacings but it is impossible to design a sample cell with a wide window for the angle dispersive di!raction method. So, for investigations under high pressure, in conditions of hydrothermal synthesis and under some mechanical in#uence, the method of energy-dispersive di!raction is used. The method of Laue di!raction is used for studying a single crystal.
* Corresponding author. Tel.: #7-3832-394145; fax: #73832-342163, 7-3832-322847. E-mail address: [email protected] (A.I. Ancharov).
The new experimental station installed on SR beamline N7 of the VEPP-4 storage ring (Fig. 1) is intended for studies by these methods [1]. Development and construction of the station was realized within the framework of Indo-Russian Long-Term Program of cooperation in science and technology (ILTP). Three organizations participate in this project. They are Institute of Solid State Chemistry and Mechanochemistry, Budker Institute of Nuclear Physics (both in Novosibirsk, Russia) and Bhabha Atomic Research Center (Bombay, India). Beamline N7 receives radiation from magnet IV ("eld of 9.4560 kG). The critical energy and wavelength are 22.6 keV and 0.55 As , respectively. The X-ray beam passes from the storage ring in an evacuated beam pipe on the hutch. The beam pipe is divided into three sections. The "rst section has common vacuum with the storage ring and is separated from the next sections by four beryllium
0168-9002/00/$ - see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 0 0 ) 0 0 2 0 9 - 6
A.I. Ancharov et al. / Nuclear Instruments and Methods in Physics Research A 448 (2000) 126}128
Fig. 1. General view of station. On the right there are the collimator block and monochromator. The experimental hutch is on the left.
foils. Gaps between the foils are pumped by storage ring pumps. The next section has a foil, mounted in the entrance of the primary collimator block. Vacuum of this section is ensured by two magnetodischarge pumps, installed above the beam pipe. Three luminophor SR beam position monitors and three vacuum manometers are installed in the second section. The third channel section inputs radiation inside the experimental hutch. It ends with a beryllium foil 150 lm thick, installed on the #ange of the telescopic tube. Pumping-out of the third beamline section is produced by a vacuum pump with the liquid-nitrogen trap. Full thickness of the beryllium foils installed in the beamline is 1 mm. At a distance of 37 m from the point of radiating at the beginning of the third section a primary collimator is installed in the vacuum box 500;500;500 mm in size. The collimator consists of two vertical and two horizontal tantalum plates, installed on translation stages. An identical box is installed immediately behind the "rst box. It is intended for installation of a monochromator. Usage of a monochromator allows one to implement the scheme of precise energy-dispersive diffractometry. Experimental hutch (Fig. 2) is a vacuum-tight box made of 20 mm stainless steel with an internal size of 1100;870;680 mm. Two optical benches are installed in the box as a support for the
127
Fig. 2. Experimental hutch and two-coordinate detector DED-5.
equipment, including: (1) Ionization chamber for intensity monitoring of the primary beam, (2) Precision collimator with tantalum slits [2], (3) X}Z translation stage for collimator displacement, (4) High-pressure diamond anvil cell, (5) X}Z}H}u translation stage for the sample. Two types of detectors are used at stations: (1) liquid-nitrogen-cooled solid-state high-purity germanium detector `ORTECa is used in the energy-dispersive di!raction experiments; (2) two-coordinate detector `DED-5a is used in the Laue di!raction experiments. Both detectors are installed on the platform of the vertical translation stage. This mechanism gives a possibility for vertical movement of the detector up to 900 mm. One end of the platform is installed on a horizontal axis, which allows change of sloping of the detector from !53 to 303. Two types of output collimators can be used in the energy-dispersive di!raction method. The "rst type of collimator is a system of two tantalum slits with controlled size and position. The second type of collimator, made with a coniform slit, is installed near the semiconductor detector. The coniform slit allows collecting all radiation di!racted at a "xed angle. Use of a coniform slit raises system e$ciency,
SECTION IV.
128
A.I. Ancharov et al. / Nuclear Instruments and Methods in Physics Research A 448 (2000) 126}128
Fig. 3. Test Laue pattern obtained from a single crystal of quartz on the detector DED-5. (E"4.5 GeV, I"0 mA, time of exposition is 10 s.)
which is important for experiments with small amounts of material. Two-coordinate detector DED-5 was designed and made at Budker Institute of Nuclear Physics, Novosibirsk. This model [3] has two-coordinate multi-wired proportional chamber with an aperture 386;386 mm in size. The detector has 65536 channels 1.5;1.5 mm in size. The detector has two working modes: increment accumulation of data and the frame-by-frame mode. In the "rst regime, information on photon coordinates is stored in the special incremental memory. In the second mode, data are recorded to the memory (event by event); besides the coordinates, energy of photons and time of events are also recorded. Memory volume in the
frame-by-frame mode is 8 million events. The minimal frame time is about 100 ls. First test experiments on the station were conducted in April, 1998. Fig. 3 shows the Laue pattern from a single crystal of quartz.
References [1] A.I. Ancharov, B.P. Tolochko, R. Chidambaram et al., Nucl. Instr. and Meth. A 359 (1999) 206. [2] I.P. Dolbnya, N.G. Gavrilov, N.A. Mezentsev, V.F. Pindyurin. Rev. Sci. Instr. 63 (1992) 609. [3] V.M. Aulchenko, S.E. Baru, M.S. Dubrovin et al., J. Synch. Radial. 5 (1998) 263.