Sector of Low Temperature, DLNP
At present time, the basic directions of research pursued by SLT are:
Frozen polarized targets
This is the traditional direction of research at LNP. In 1975 one of the first-ever frozen targets has been started on the phasotron of LNP.(JINR communications 13-10253, 13-10257, Dubna, 1976; JETP, 73 (1977) 1679). To create the target, the dilution of 3He in 4He method to get ultra low temperatures was applied. This method was first successfully realized in LNP JINR (JETP, 50 (1966) 1445). The targets of this type constructed by LNP researchers are used at experiments in several scientific centers: IHEP, PINP, Prague University. Thus, the staff of the SLT mainly consists of researchers who have been constructing and maintaining the frozen polarized targets for many years (Yu.A. Usov, NIM A 526 (2004) 153-156)..
NN - Interactions-Prague (theme 2-02-1042-2002/2006, leader A.S.Kurilin). Polarized target for this experiment was built at LNP with participation of Czech researchers in 1994. The research program of (np)-interactions at low energies was finished by 2000, the results were reported (Int. Symp. FB 16, Taipei, 2000; Int. Workshop “Symmetry and Spin”, Prague, 2000; 14-th Int.Symp. on High Energy Spin Physics, Osaka , 2000).
At present, the investigation program of (nd)-interactions at low energies is being realized. For these purpose, a modification of the polarized target has been carried out, a new system of data acquisition and processing has been created. By the middle of 2006, the three runs of data acquisition have been carried out. Preliminary results have been published (J.Klouzal et al. “Measurement of spin dependent total cross sections in neutron-deuteron scattering”, in Prîc. of the European Conference on Few-Body Problems in Physics, 2005). As a whole, the aim of the project is the measurement of the difference of total cross-sections ?? (L, T) for investigation of 3N-interaction with the polarized neutron beam and polarized deuteron target in the energy region 14 – 16 MeV where according to the last theoretical predictions the effect of 3NF should be evident especially strongly. It should be mentioned that the investigations carried out in Prague were for the last time the only example at JINR of the experiment at the accelerator of a JINR participant.
MPT – LHE JINR (theme: 3-01-0941-92/2005, leader N.M. Piskunov). Movable polarized target. This installation earlier was used in Fermilab and later it was modified in a "movable" variant by experts from JINR, Saclay, PINP, INR and KhPTI at support of fund " INTAS ". Since 1995, researches on measurement ?? L (np) - difference of the total cross sections on the synchrophasotron of VBLHE have been spent and in the last run (October-2001) are practically successfully completed, at longitudinal polarization of the target and beam (Eur. Phys. J. C 37 (2004) 79). In plans of near future - carrying out experiments with transversal polarization of the target and beam for which aim the completion of a "Holding Magnet " and performance of some other work is necessary. Employees of the sector are busy in this experiment not only in the work connected with the polarized target, but are also engaged in processing physical data. Work on completion and use of installation "ÌÐÒ" - have been considered as the separate project since 2002 that will allow, we hope, to realize these plans to the full.
RAMPEX – IHEP In IHEP, the researches on ðð-interactions are carried out at 70 ÃýÂ. We do not have formal obligations on these works, nevertheless, to spend the experiments with use of the polarized target created by employees of LNP (N. S. Borisov, et al., Prib. Techn. Exp. 2 (1978) 32) without participation of employees of SLT is not possible yet. In 2000 and 2005, three monthly runs have been carried out with our participation, now data processing is conducted (A.N.Vasilev et al., Preprint IHEP, 2004-32, Protvino, 2004). Now our colleagues from IHEP have prepared the project "SPASCHARM" - Studying of spin asymmetries and formation charmonium at accelerator U-70 ". This project assumes modernization of the existing or creation of the new polarized target and the employees of SLT plan to participate in this work in some form.
GDH "GDH" is the new project prepared at SLT on experimental check of a rule of the sums of Gerasimov-Drell-Hearn (GDH). At LNP the CRYOSTAT for a polarized target has been developed and made for this experiment. The physical program of the project is realized at the modified accelerator " MAMI C " (Mainz) since 2007. Thus, the main distinctive features of this project is not only realization in foreign experiment of the physical idea put forward by the scientist from JINR (S. Gerasimov, Yad. Fiz. 2 (1966) 598), but also getting additional finances for realization of JINR obligations, under the given project, from the German party (Contract 1420-1820/-3).
Participation in ATLAS project (theme 02-0-1007-94/2005, leader N.A. Rusakovich)
Researchers of SLT became actively involved in work on manufacturing and tests of assembly units of the hadron liquid argon calorimeter. The work was carried out in specially created “clean room” (room 112, building 113, LNP). 24 units were manufactured, tested and consigned to CERN to date. It was a costly and exclusively responsible job. Besides, the researchers of the sector participate in processing data obtained in the run “Test Beam” (ATLAS note, ATL-COM-LARG-2001-019; NIM A 482, (2002) 92-24). Also, our participation in creation of the temperature measurement system in ATLAS cryostats was quite successful: this system is in operation at the liquid argon cryostat on H6 beam (CERN); the work on the precision calibration of the 700 platinum thermometers (PT-100) is completed, according the contract between CERN and JINR (AGREEMENT No. K 631/ EP / ATL). All data on this theme are placed at the specially created page “Temperature Measuring System” of the web-site of ATLAS project. Considering the results of this methodic work, our collaborators in CERN explicitly proposed us to be a responsible party for creation of the temperature measurement system and, may be, also “Slow Control” in whole, but this did not happen on some causes. The results of this methodic work were published (NIM A 526 (2004), 153-156).
Participation in innovative project “MAGNETIC RESONANCE IMAGER”
This project was set up for 2003-2006 as a part of the program of the development of Dubna as NAUKOGRAD (Science Town) of the Russian Federation. Authors of the project, JINR researchers ( LNP, LHE, LNP), wined the first town competition of innovative projects, as our project (leaders Yu.A. Plis and V.V. Fimushkin) was the most expensive and longest one. Supposed finances from the federal and regional budget was 30 millions rubles. After realization in 2004 of the first two steps of the project, the administrations of town and JINR decided to hang up fulfillment of the project. At the same time, to date, the authors of the project have prepared (taking into account the received experience) a renewed proposal “Universal pulsed magnetic resonance imager”. We hope that this project will be some time in demand in Russia, especially in relation of creation in Dubna of “the special economic zone” and development of the innovative themes in JINR (it is possible to acquaint with a text of the project at this site).
Plans and outlook.
Prolongation and extension of the initiate work:
Project “MPT” (theme: 3-01-0941-91/2009);
Project “NN” & “GDH” (theme: 2-02-1042-2002/2009);
Project “ATLAS” (theme: 02-0-1007-94/2008).
Two first projects continue the chief research directions of SLT – the application of ultra low temperatures (“frozen” polarized targets) for study of spin-dependent effects in particle interactions. The project “MPT” is proposed, apart from the work on improvement of parameters and increase of reliability of all the system of the setup, to realize the entirely new capacity – transverse polarization of the target. This would permit to realize the supported projects of LHE: “BES”, “SINGLET”, “DELTA-SIGMA”. The employees of SLT consider as very important and prospective direction of their future job the possible participation in the new innovative and scientific projects with use of cryogenic and polarization techniques (“ILC”, “NICA”…).
21.03.2007 . /Usov Yu.A./
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