HIRFL���CSR的匹配研究

国家重大科学工程HIRFL CSR冷却储存环计划主环CSRm利用已有的HIRFL���为注入器 ,为了更好地利用HIRFL���速器的能力 ,对这两台加速器的匹配在原来的初步考虑的基础上进行了较为详细的研究 ,提出了分别利用HIR FL���己的注入器SFC单独注入到CSR以及SFC加上主加速器SSC注入到CSR的两套方案 ,既可以提高HIRFL���CSR的总传输效率 ,又可以在SFC与CSR联合运行的同时使SSC与另建的小回旋加速器组合加速质子 ,从而充分提高HIRFL���运行效率

An outlook of heavy ion driven plasma research at IMP-Lanzhou

Since the successful completion of the cooling storage ring (CSR) project in China at the end of 2007, high qualitative heavy ion beams with energy ranging from keV to GeV/u have been available at the Heavy Ion Research Facility at Lanzhou (HIRFL). More than 10(9) 1 GeVlu C6+ particles or 10(8) 235 MeV/u Xe particles can be stored in the CSR main-ring and extracted within hundred nano-seconds during the test running, the beam parameters will be improved in the coming years so that high energy density (HED) conditions could be achieved and investigated there. Recent scientific results from the experiments relevant to plasma research on HIRFL are summarized. Dense plasma research with intense heavy ion beams of CSR is proposed here.

Alleviation of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma-ray on male reproductive endocrine damages induced by subsequent high-dose irradiation

Irradiation has been widely reported to damage organisms by attacking on proteins, nucleic acid and lipids in cells. However, radiation hormesis after low-dose irradiation has become the focus of research in radiobiology in recent years. To investigate the effects of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma (gamma)-ray on male reproductive endocrine capacity induced by subsequent high-dose irradiation, the brains of the B6C3F(1) hybrid strain male mice were irradiated with 0.05 Gy of C-12(6+) ion or Co-60 gamma-ray as the pre-exposure dose, and were then irradiated with 2 Gy as challenging irradiation dose at 4 h after pre-exposure. Serum pituitary gonadotropin hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), testosterone, testis weight, sperm count and shape were measured on the 35th day after irradiation. The results showed that there was a significant reduction in the levels of serum FSH, LH, testosterone, testis weight and sperm count, and a significant increase in sperm abnormalities by irradiation of the mouse brain with 2 Gy of C-12(6+) ion or Co-60 gamma-ray. Moreover, the effects were more obvious in the group irradiated by C-12(6+) ion than in that irradiated by Co-60 gamma-ray. Pre-exposure with low-dose C-12(6+) ion or Co-60 gamma-ray significantly alleviated the harmful effects induced by a subsequent high-dose irradiation.

Chromosomal aberrations induced by C-12(6+) ions and Co-60 gamma-rays in mouse immature oocytes

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of C-12(6+) ion or Co-60 gamma-ray. Chromosomal aberrations were analyzed in metaphase II oocytes at 7 weeks after irradiation. The relative biological effectiveness (RBE) of C C-12(6+) ion was calculated with respect to Co-60 gamma-ray for the induction of chromosornal aberrations. The C-12(6+) ion and Co-60 gamma-ray dose-response relationships for chromosomal aberrations were plotted by linear quadratic models. The data showed that there was a dose-related increase in frequency of chromosomal aberrations in all the treated groups compared to controls. The RBE values for C-12(6+) ions relative to (CO)-C-60 gamma-rays were 2.49, 2.29, 1.57, 1.42 or 1.32 for the doses of 0.5, 1.0, 2.07 4.0 or 6.0 Gy, respectively. Moreover, a different distribution of the various types of aberrations has been found for C-12(6+) ion and Co-60 gamma-ray irradiations. The dose-response relationships for C-12(6+) ion and (CO)-C-60 gamma-ray exhibited positive correlations. The results from the present study may be helpful for assessing genetic damage following exposure of immature oocytes to ionizing radiation.

Slow highly charged ion O4+ induced electron emission from clean solid surfaces

The. total electron emission yields following the interaction of slow highly charged ions (SHCI) O4+ with different material surfaces (W, Au, Si and SiO2) have been measured. It is found that the electron emission yield gamma increases proportionally with the projectile velocity v ranging from 5.36 x 10(5)m/s to 10.7 x 10(5)m/s. The total emission yield is dependent on the target materials, and it turns out to follow the relationship gamma(Au) > gamma(Si)> gamma(W). The result shows that the electron emission yields are mainly determined by the electron stopping power of the target when the projectile potential energy is taken as a constant, which is in good agreement with the former studies

X-ray spectra induced by Xe-129(q+) impacting the metal surface

Using the slow highly charged ions Xe-129(q+) (q = 25, 26, 27; initial kinetic T-0 <= 4.65 keV/a.u.) to impact Au surface, the Au atomic M alpha characteristic X-ray spectrum is induced. The result shows that as long as the charge state of projectile is high enough, the heavy atomic characteristic X-ray can be effectively excited even though the incident beam is very weak (nA magnitude), and the X-ray yield per ion is in the order of 10(-8) and increases with the kinetic energy and potential energy of projectile. By measuring the Au M alpha-X-ray spectra, Au atomic N-level lifetime is estimated at about 1.33x10(-18) s based on Heisenberg uncertainty relation.

The electron emission yield induced by the interaction of highly charged argon ions with silicon surface

The electron emission yield of the interaction of highly charged argon ions with silicon surface is reported. The experiment was done at the Atomic Physics Research Platform on the Electron Cyclotron Resonance (ECR) Ion Source of the National Laboratory HIRFL (Heavy Ion Research Facility in Lanzhou). In the experiment, the potential energy and kinetic energy was selected by varying the projectile charge states and extracting voltage, thus the contributions of the projectile potential energy deposition and electronic energy loss in the solid are extensively investigated. The results show that, the two main factors leading to surface electron emission, namely the potential energy deposition and the electronic energy loss, are both approximately proportional to the electron emission yield per ion.

Pre-irradiation with low-dose C-12(6+) beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in C-12(6+) beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in gamma-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G(0)/G(1) arrest and activated G(2)/M checkpoints. The pre-exposure to C-12(6+) beam significantly improved cell to apoptosis. RBEs for the C-12(6+)+ AdCMV-p53 infection groups were 30%-60%,20% -130% and 30%-70% more than those for the C-12(6+)_irradiated only, AdCMV-p53 infected only, and gamma-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose C-12(6+) beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

X-ray emission of hollow atoms formed by highly charged argon and xenon ions below a beryllium surface

The X-ray emission induced by highly charged argon and xenon ions impinging on a beryllium surface is investigated. It is found that spectra of the X-ray induced by Ar-17,Ar-18+ interacting with the surface are very different from those of the X-ray induced by Ar-17,Ar-18+ interacting with residual gases. The result provides an experimental evidence for the existence of hollow atoms below the surface. Several unexpected X-ray lines are also found in the experiment. Firstly, K X-rays are observed when Ar16+ ions which initially have no K shell holes interact with the surface. Secondly, if there are more than 2 M shell vacancies at the initial time, strong M alpha alpha two-electron-one-photon (TEOP) transitions are found in the collisions of Xe-28+,Xe-29+,Xe-30+ ions with the surface.

Adaptive hormetic response of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma-ray on growth hormone (GH) and body weight induced by subsequent high-dose irradiation

The brain of the Kun-Ming strain mice were irradiated with 0.05 Gy of C-12(6+) ion or Co-60 gamma-ray as the pre-exposure dose, and were then irradiated with 2 Gy of 12C6+ ion or Co-60 gamma-ray as challenging irradiation dose at 4 h after per-exposure. Body weight and serum growth hormone (GH) concentration were measured at 35th day after irradiation. The results showed that irradiation of mouse brain with 2 Gy of C-12(6+) ion or Co-60 gamma-ray significantly diminished mouse body weight and level of serum GH. The relative biological effectiveness values of a 2 Gy dose of C-12(6+) ion calculated with respect to Co-60 gamma-ray were 1.47 and 1.34 for body weight and serum GH concentration, respectively. Pre-exposure with a low-dose (0.05 Gy) of C-12(6+) ion or Co-60 gamma-ray significantly alleviated reductions of mouse body weight and level of serum GH induced by a subsequent high-dose (2 Gy) irradiation. The data suggested that low-dose ionizing irradiation can induce adaptive hormetic responses to the harmful effects of pituitary by subsequent high-dose exposure.

Germ cell loss induced by C-12(6+) ion irradiation in young female mice

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of C-12(6+) ion in the Bragg peak or the plateau region. At 10th day after irradiation, ovarian and uterine weights were measured: normal and atretic (identified with the oocyte to be degenerating or absent) primordial, primary and preantral follicles were identified in the largest cross-section of each ovary. Percentage (%) of normal follicles of each developmental stage of oogenesis was calculated. The data showed that compared to controls, there was a dose-related decrease in percentage of normal follicles in each developmental stage. And the weights of ovary and uterus were also reduced with doses of irradiation. Moreover, these effects were much more significant in the Bragg peak region and the region close to the Bragg peak than in the beam's entrance (the plateau region). Radiosensitivity varied in different follicle maturation stages. Primordial follicles, which are thought to be extremely sensitive to ionizing irradiation, were reduced by 86.6%, while primary and preantral follicles reduced only by 72.5% and 61.8% respectively, by exposure with 6 Gy of C-12(6+) ion in the Bragg peak region and the region close to the Bragg peak. The data suggested that due to their optimal depth-dose distribution in the Bragg peak region, heavy ions are ones of the best particles for radiotherapy of tumors located next of vital organs or/and surrounded by normal tissues, especially radiosensitive tissues such as gonads.

X-ray spectra induced in highly charged Ar-40(q+) interacting with Au surface

By use of optical spectrum technology, the spectra of X-ray induced by highly charged Ar-40(q+) ions interacting with Au surface have been studied. The results show that the argon K alpha X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ ion, with electronic configuration 1s(2) in its ground state below the solid surface. The yield of the projectile K alpha X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

X-ray spectroscopy of hollow argon atoms formed on a beryllium surface

The X-rays induced during interaction of highly charged argon ions with a beryllium surface are reported. It is found that the K shell X-ray yield of single particle during interaction of hydrogen-like argon ions was 3.6 x 10(-3), which is five orders more than that of heliumlike argon ions. Moreover, due to the screening the 2s electron, no K X-ray was emitted during interaction of lithium-like argon ions with the beryllium surface. It is also found that the X-ray spectrum induced by Ar17+ interacting with residual gases is very different from that induced by Ar17+ interacting with the surfaces, that provided an experimental evidence for the existence of the hollow atoms below the surface.

Ginsenoside R-e increases fertile and asthenozoospermic infertile human sperm motility by induction of nitric oxide synthase

We investigated the effects of Ginsenoside R-e on human sperm motility in fertile and asthenozoospermic infertile individuals in vitro and the mechanism by which the Ginsenosides play their roles. The semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Spermatozoa were separated by Percoll and incubated with 0, 1, 10 or 100 mu M of Ginsenoside R-e. Total sperm motility and progressive motility were measured by computer-aided sperm analyzer (CASA). Nitric oxide synthase (NOS) activity was determined by the H-3-arginine to H-3-citrulline conversion assay, and the NOS protein was examined by the Western blot analysis. The production of sperm nitric oxide (NO) was detected using the Griess reaction. The results showed that Ginsenoside R-e significantly enhanced both fertile and infertile sperm motility, NOS activity and NO production in a concentration-dependent manner. Sodium nitroprusside (SNP, 100 nM), a NO donor, mimicked the effects of Ginsenoside R-e. And pretreatment with a NOS inhibitor N-omega-Nitro-L-arginine methyl ester (L-NAME, 100 mu M) or a NO scavenger N-Acetyl-L-cysteine (LNAC, 1 mM) completely blocked the effects of Ginsenoside R-e. Data suggested that Ginsenoside R-e is beneficial to sperm motility, and that induction of NOS to increase NO production may be involved in this benefit.

Solvent extraction of americium and europium ions by amide-derivatized polyethers from picric acid aqueous solution

The extraction of Am3+ and Eu3+ from picric acid aqueous solution by N,N-1,2-ethanediyl-bis[2-(N,N-diphenyl-carbamoyl-methoxy)-benzamide] was investigated by a radioactive tracer technique. The composition of the extracted species has been determined as ML(Pic)(3) (M = Eu, Am). The effect of various parameters such as pH, organic diluents, different extractants, picric acid concentration and extractants concentration on the extraction of Am3+ and Eu3+ has been studied. The extraction equilibrium mechanism has been also evaluated and discussed.