Present status of an accelerator mass spectrometry (AMS) facility at BINP is described. The AMS facility with

addition electric and magnetic analyzers into a terminal of a tandem accelerator is designed for precise analyses of

carbon isotopes at extremely low concentration levels.Рассмотрено текущее состояние работ по созданию в ИЯФ им. Г.И.Будкера ускорительного масс-спек-

трометрического комплекса (AMS). Комплекс AMS c дополнительным электрическим и магнитным анали-

заторами, расположенными в области терминала тандемного ускорителя, предназначен для прецизионного

анализа предельно низкой концентрации изотопов углерода.Розглянуто поточний стан робіт з створення в ІЯФ ім. Г.І. Будкера прискорювального мас-

спектрометричного комплексу (AMS). Комплекс AMS c додатковим електричним і магнітним

аналізаторами, розташованими в області термінала тандемного прискорювача, призначений для

прецизійного аналізу гранично низької концентрації ізотопів вуглецю

Alinovsky, N.I.

Bulushev, A.F.

Klyuev, V.F.

Konstantinov, E.S.

Konstantinov, S.G.

Kozhemyakin, A.V.

Kryuchkov, A.M.

Parkhomchuk, V.V.

Petrichenkov, M.V.

Rastigeev, S.A.

Reva, V.B.

Sukhina, B.N.

PubMed

Наукова електронна бібліотека періодичних видань НАН України (Vernadsky National Library of Ukraine)

STATUS OF AN ACCELERATOR MASS-SPECTROMETER PROJECT FOR SD RASN.I. Alinovsky, A.F. Bulushev, V.F. Klyuev, E.S. Konstantinov, S.G. Konstantinov,  A.V. Kozhemyakin, A.M. Kryuchkov, V.V. Parkhomchuk, M.V. Petrichenkov, S.A. Rastigeev,  V.B. Reva, B.N. Sukhina Budker INP, Novosibirsk, RussiaE-mail: S.A.Rastigeev@inp.nsk.su Present status of an accelerator mass spectrometry (AMS) facility at BINP is described. The AMS facility with addition electric and magnetic analyzers into a terminal of a tandem accelerator is designed for precise analyses of carbon isotopes at extremely low concentration levels.PACS: 29.30.Aj1. INTRODUCTIONThe status of the BINP AMS facility and the recent development are described. The construction work start-ed in 2003, and the project has been presented previous-ly [1]. Fig.1 shows the layout of the AMS facility.Fig.1. AMS facility layout:1 − pressure tank; 2 − accelerator tube; 3 − cascade generator; 4 − combined filter; 5 − magnesium vapors  stripper, 6 − ion source; 7 − low-energy magnetic an-alyzer; 8 − high-energy magnetic analyzerThe AMS is based on an electrostatic tandem accel-erator. The most distinguishing feature of our AMS ma-chine is the use of additional separator of ion beam, lo-cated inside the terminal. The addition of electric and magnetic  analyzers  can essentially  decrease  the back-ground. Interfering isobaric molecules are destroyed by collisions in the stripper into the terminal and selected immediately after  stripping process.  It  is  important  to decrease the background from molecular fragments be-fore  the  second  acceleration  stage  because  otherwise they can  obtain large energy spread by recharging on residual gas into electric field. The ions in charge state 3+  will  be  used  for  isotope  analysis  because  the molecules in charge state 3+ are unstable. The next im-portant  distinguishing  feature  is  magnesium  vapors stripper instead of the gas stripper. Therefore, it is not necessary  to  use  additional  turbo-molecular  pump for good vacuum condition outside the magnesium vapors stripper.2. INJECTION SYSTEMA photograph of  the injection system is shown in Fig. 2.Fig.2. Injection systemThe AMS system has two ion sources. The sputter ion source is required for analysis of solid samples. The gas ion source is needed for direct analysis of gas sam-ples and for system adjustment. The injection energy of the extracted negative ions is 15 keV. The ion beam ex-tracted from the source passes through a double focus-ing 90° analyzing magnet, with 40 cm radius and 2.5 cm pole gap. The position and angles of extracted beam are slightly  corrected  by  four  pairs  of  electrostatic  plate. During radiocarbon measurements the carbon isotopes will be passed through magnet by additional voltage ap-plied to the vacuum chamber of magnet. The stable iso-tope currents are measured during time of the injection of the radioisotope beam by offset Faraday cups placed __________________________________________________________PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 2.        Series: Nuclear Physics Investigations (46), p.34-36.34after injection magnet. In order to set up the size and po-sition of  injection beam into the stripper  channel,  the system of three-electrode electrostatic lenses and elec-trostatic dipoles are manufactured and will be placed at the entrance of the accelerating tube. The vacuum of the injection channel is kept better than 5*10-6 Torr by 400 l/s ion pump. A new 250 l/s turbo-molecular pump is now installed  just  behind  ion  sources.  The  beam-line from ion  source  to  accelerator  tube  is  completed  and tested.3. TANDEM ACCELERATORThe AMS tandem accelerator is a folded type verti-cal machine with 180° bending system in the high volt-age terminal. A photograph of the tandem accelerator is shown in Fig.3.Fig.3. Tandem acceleratorThe negative ions will be accelerated to the positive-ly charged high voltage terminal and stripped to 3+ state in charge exchange target. Then they pass through the 1800 combined bend and then again are accelerated into the high energy accelerating tube to the ground poten-tial. The two accelerating tubes and cascade generator are  enveloped  by  shielded  column,  which  is  200 cm high and 140 cm outside diameter  of  shielding rings, and placed into a pressure tank. The dimensions of pres-sure tank are 4.6 meters high and 3.2 meters diameter. The accelerating tube consists of five sections, with 21 mm  electrode  step.  The  electrodes  are  divided  by ceramic rings with 18 cm inner diameter.  The channel aperture  of  accelerator  tube  is  3 cm.  Resistor  chains achieve the potential gradients across the columns and tube electrode gaps. The maximal designed gradient in the tube is a little larger than 10 kV/cm. The accelerat-ing  voltage  is  generated  by  the  symmetrical  cascade generator with a resonance frequency around 20 kHz. The project terminal voltage has value 2 MV, with SF6 insulating gas, at 1.7 atm pressure. At present, while in the commissioning phase, the accelerator is used with air at 1 atm pressure as insulating gas instead of sulfur hexafluoride  gas.  The  maximal  terminal  voltage  of 500 kV was demonstrated during the installation period, with air being the insulating gas. The SF6 gas is now stored  in  the  external  tanks.  The  gas  transfer  system with the compressor and the dryer containing silica gel is completed. The accelerating tubes, the cascade gener-ator, the shielded column, and the terminal shell are also installed into the tandem tank.4. MAGNESIUM VAPORS STRIPPERThe use of magnesium vapors stripper allows obtain-ing the vacuum level in accelerating tubes being compa-rable with systems with solid targets because  the mag-nesium vapor is condensed into the special containers at the room temperature, which are placed at the entrance and exit of the stripper tube. Solid targets at these ener-gies have a short lifetime and therefore are not applied usually. The high gas flow into the high-energy tubes leads to large energy spread in the beam thus limiting the sensitivity and accuracy of a spectrometer. The mag-nesium vapors stripper was manufactured and is shown in Fig.3.Fig.4. Magnesium vapors stripperThe stripper channel has a length of 30 cm and the inner diameter of 3 mm. The stripper tube is enveloped by the container with the solid magnesium. When the container is heated, the magnesium vapors follow from the container through  the small  holes  to  the  stripper tube. In order to check the efficiency of the magnesium vapor stripper, the elegant experiment was performed. In this experiment, a thin tungsten wire is strained along the stripper tube axis. The container with the solid mag-nesium is heated by current flowing through it. The test wire temperature is varied as shown in Fig.5.Fig.5. The test wire temperature as a function of the container temperature with the solid magnesiumAt first, the wire temperature increases with increas-ing the  stripper tube temperature by exchange of ther-__________________________________________________________PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 2.        Series: Nuclear Physics Investigations (46), p.34-36.34400 420 440 460 480 500 520 540 560 580610620630640650660670  test wire temperature , 0  Ctemperature of the container with the solid magnesium, 0 Cmal radiation energy between the wire and stripper tube. Then the temperature of wire reduces because the wire is cooled by thermal conductivity of the magnesium va-por, which pressure is increased dramatically with  in-creasing  of  the  magnesium  heating  temperature.  The magnesium vapors pressure is ~10-10  Torr at room tem-perature  and  rises  up  to  ~5·10-2 Torr  at  ~500оC. The temperature range of 450 to 500°C provides the suffi-cient thickness of target for radiocarbon dating measure-ments.  The previously developed analogue of such tar-get has worked for more than 500 hours on the electron cooling investigation facility [2].5. HIGH ENERGY BEAM SELECTIONThe filter with  electric and magnetic fields will be mounted  immediately behind  the  magnesium stripper, both have 40 cm radius and 180° bending angle. The electrostatic plates are placed into the magnet. The dis-tance  between  the  electrostatic  plates  is  1 cm,  these plates are of spherical form, thus providing a double fo-cusing of a beam. The magnet has uniform field in the gap with 600 Gs maximal field that is quite enough for mass selection. The 90 % of centripetal force are ob-tained by electrostatic field, with ~30 kV/cm maximal field at 2 MV accelerating voltage. The most fractions of the unwanted particles should be removed by this se-lector. This terminal selector is now under construction. For better background filtration, the next 90° analyzing magnet will be placed at the exit of the tandem accelera-tor. The carbon radioisotope particles will be measured by a silicon surface barrier detector placed at the end of beam line [1].6. CONTROL SYSTEMThe  fully  computer  controlled  system is  designed and partly manufactured. The software used for the con-trol  system is based on the LabVIEW. The system is equipped with ADAM and CAMAC modules. The ex-periment  parameters  and  running  conditions  are  dis-played on-line. These data are stored in a database and can be used as initial values for the beam tuning. All de-vices at high voltage potentials are controlled through an optical ADAM link system in communication with the computer.  The gaseous turbine  will be placed  into the  tandem terminal  for  powering  the  equipment  into terminal. The turbine will be rotated by compressed air flowed from the  compressor,  which  will  be placed at ground  potential. The  prototype  of  such  turbine  was made and tested. A photograph of the gaseous turbine is shown in Fig.6.Fig.6. Gaseous turbineThe power – 500 W is obtained. The efficiency fac-tor of turbine is about 10%. In is sufficient for powering of the all equipment into tandem terminal. New turbine with 20% efficiency factor was designed.SUMMARYThe low-energy line is installed and in operation. By the end of 2005, a beam will be accelerated to the high voltage terminal. The work on a high-energy line will be started in the 2006 year.ACKNOWLEDGMENTSThis work is  supported by FASIE* foundation and by INTAS#.REFERENCES 1. N. Alinovsky et al. The project of accelerator mass  –spectrometr  at  BINP.  Proc.  of  EPAC  2004, Lucerne. 2004.2. V. Parkhomchuk,  A. Seriy. Strip  target  based  on magnesium vapors // Instruments and Experimental  Techniques. 1989, v.5, p.59-61.* www.fasie.ru# (IA 03-59-120) СОСТОЯНИЕ РАБОТ ПО ПРОЕКТУ УСКОРИТЕЛЬНОГО МАСС-СПЕКТРОМЕТРА ДЛЯ СО РАНН.И. Алиновский, А.Ф. Булушев, В.Ф. Клюев, Е.С. Константинов, С.Г. Константинов, А.В. Кожемя-кин, А.М. Крючков, В.В. Пархомчук, М.В. Петриченков, С.А. Растигеев, В.Б. Рева, Б.Н. СухинаРассмотрено текущее состояние работ по созданию в ИЯФ им. Г.И.Будкера ускорительного масс-спек-трометрического комплекса (AMS). Комплекс AMS c дополнительным электрическим и магнитным анали-заторами, расположенными в области терминала тандемного ускорителя, предназначен для прецизионного анализа предельно низкой концентрации изотопов углерода.СТАН РОБІТ ІЗ ПРОЕКТУ ПРИСКОРЮВАЛЬНОГО МАС-СПЕКТРОМЕТРА ДЛЯ СВ РАНМ.І. Алиновський, А.Ф. Булушев, В.Ф. Клюєв, Є.С. Константинов, С.Г. Константинов, А.В. Кожемякін,  А.М. Крючков, В.В. Пархомчук, М.В. Петриченков, С.А. Растигєєв, В.Б. Рева, Б.Н. СухинаРозглянуто  поточний  стан  робіт  з  створення  в  ІЯФ  ім. Г.І. Будкера  прискорювального  мас-спектрометричного  комплексу  (AMS).  Комплекс  AMS  c  додатковим  електричним  і  магнітним аналізаторами,  розташованими  в  області  термінала  тандемного  прискорювача,  призначений  для прецизійного аналізу гранично низької концентрації ізотопів вуглецю.26

Status of an accelerator mass-spectrometer project for SD RAS

Peu après la dévaluation du franc de la Communauté financière africaine (CFA) intervenue le 12 janvier 1994 dans 14 pays africains, des inquiétudes se sont exprimées quant aux conséquences qu'elle pourrait avoir, notamment en matière de santé, pour des populations déjà fragilisées par plusieurs années de crise économique d'ajustement. On prévoyait en particulier que les populations urbaines seraient très touchées. Jusqu'à présent, cette question n'a pas vraiment été analysée. Une étude préliminaire faite à Brazzaville (Congo) un an après la dévaluation a montré que la qualité des aliments de complément donnés aux nourrissons commençait à se dégrader. L'étude présentée ici visait à répondre à plusieurs questions : cette dégradation allait-elle s'inscrire dans la durée ? L'état nutritionnel des enfants allait-il lui aussi se détériorer ? La situation nutritionnelle des adultes était-elle menacée ? L'étude se fondait sur deux enquêtes nutritionnelles faites en 1993 et 1996 dans deux quartiers centraux de Brazzaville auprès d'un échantillon représentatif des ménages ayant un enfant âgé de 4 à 23 mois (n = 2623 et n = 1583, respectivement). Les deux enquêtes ont été réalisées par passage à domicile, avec la même méthodologie et le même questionnaire. On s'est servi de mesures anthropométriques normalisées pour calculer les indices de Quételet pour les mères. Pour tenir compte de certaines modifications de caractéristiques sociales des ménages en raison des troubles civils survenus à Brazzaville à la fin de 1993, nous avons ajusté les comparaisons entre les deux enquêtes pour les variables correspondantes. La dégradation de la qualité de l'alimentation de complément amorcée en 1994 s'est poursuivie en 1996 : 4 à 11 mois était moins souvent un aliment de transition spécial (48,1% en 1996 contre 58,9% en 1993, p = 0,0001)... (D'après résumé d'auteur

Martin-Prével, Yves

Delpeuch, Francis

Traissac, Pierre

Massamba, J.P.

Adoua-Oyila, G.

Coudert, Karine

Trèche, Serge

Horizon / Pleins textes

Deterioration in the nutritional status of young children and their mothers in Brazzaville, Congo, following the 1994 devaluation of the CFA franc

Red de Bibliotecas Virtuales de Ciencias Sociales de América Latina y El Caribe

The effects of the January 1994 devaluation of the African Financial Community (CFA) franc on the nutritional situation of the populations concerned has been little documented. We report in this article on two nutritional cross-sectional surveys that were conducted before and after this devaluation (1993 and 1996) in two districts of Brazzaville, Congo. The surveys involved a representative sample of 4206 households with a child aged 4-23 months. Complementary feeding practices and the anthropometric indices of the children and their mothers were compared, adjusting for changes in household socioeconomic characteristics. The results show a decline in the quality of the first complementary foods offered to the infants, i.e. less frequent use of special transitional foods and imported complementary flours (of higher nutritional quality), and preparation of less nutritious local gruels. Overall, the nutritional situation had deteriorated, with greater levels of stunting and wasting among children, mothers with lower body mass index, and infants with reduced birth weights. Increased food prices would appear to be the direct cause of the decreased quality in complementary feeding, but factors other than the devaluation have also had an impact on household welfare. The influence of these factors on nutritional status is discussed

Y Martin-Prével

Delpeuch

P Traissac

J.-P Massamba

G Adoua-Oyila

K Coudert

S Trèche

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Bulletin of the World Health Organization

http://dspace.nbuv.gov.ua/bitstream/handle/123456789/78696/10-Alinovsky.pdf?sequence=1

Status of an accelerator mass-spectrometer project for SD RAS

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Наукова електронна бібліотека періодичних видань НАН України (Vernadsky National Library of Ukraine)

Horizon / Pleins textes

Red de Bibliotecas Virtuales de Ciencias Sociales de América Latina y El Caribe

Directory of Open Access Journals