{"_buckets": {"deposit": "a0333051-9f7a-450a-bcf3-4bd86cabab6d"}, "_deposit": {"created_by": 21, "id": "1461", "owners": [21], "pid": {"revision_id": 0, "type": "depid", "value": "1461"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00001461", "sets": ["9"]}, "author_link": ["0", "0", "0"], "item_1_biblio_info_21": {"attribute_name": "書誌情報（ソート用）", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "2009-03-24", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "Md.,Serajul,Islam,Prodhan"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "モハメド, セラジュル イスラム プロドハン"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_date_granted_11": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "2009-03-24"}]}, "item_1_degree_grantor_5": {"attribute_name": "学位授与機関", "attribute_value_mlt": [{"subitem_degreegrantor": [{"subitem_degreegrantor_name": "総合研究大学院大学"}]}]}, "item_1_degree_name_6": {"attribute_name": "学位名", "attribute_value_mlt": [{"subitem_degreename": "博士（理学）"}]}, "item_1_description_1": {"attribute_name": "ID", "attribute_value_mlt": [{"subitem_description": "2009009", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": "　　Two major topics of his thesis are (i) development of the velocity map\u003cbr /\u003e imaging (VMI) spectrometer for investigation of the photoion images of\u003cbr /\u003efullerenes, and (ii) simulation studies of possible processes for C\u003csmall\u003e60\u003c/small\u003efragmentation. \u003cbr /\u003eThere are two plausible photofragmentation pathways of excited C\u003csmall\u003e60\u003c/small\u003e cations, \u003cbr /\u003enamely the stepwise C\u003csmall\u003e2\u003c/small\u003e-loss and direct fission processes. Several groups have\u003cbr /\u003etried to distinguish these two processes by measuring the total average kinetic\u003cbr /\u003eenergy release (KER) in the decompositkxr of C\u003csmall\u003e60\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e into C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e and smaller\u003cbr /\u003efragments. Such efforts, however, have met with failure. The portion of the KER\u003cbr /\u003epartitioned to the ionic fragments was found to be a few tens of \u003cbr /\u003emillielectronvolts and is comparable to or smaller than the average thermal\u003cbr /\u003eenergies of neurtal C\u003csmall\u003e60\u003c/small\u003e molecules in an effusive beam. The above two processes\u003cbr /\u003etherefore give C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e and smaller fragments with similar average kinetic energies\u003cbr /\u003ein the laboratory system. Obviously, we must measure a precise 3D velocity\u003cbr /\u003edistribution, speed and angular distributions, to gain helpful clue to decide on\u003cbr /\u003ewhich process is more dominant. For this purpose we have developed a VMI\u003cbr /\u003espectrometer that is very sensitive to thermal ions having small translational\u003cbr /\u003e energies.\u003cbr /\u003e　　　Our VMI spectrometer is based on a time-of-flight (TOF) technique for\u003cbr /\u003ethe fragment ions produced by irradiation of synchrotron radiation. Its basic\u003cbr /\u003eperformance has been experimentally tested by using five rare gases at photon\u003cbr /\u003eenergy \u003ci\u003ehv\u003c/i\u003e=35 eV. The 3D velocity distributions were reconstructed by using\u003cbr /\u003ethe inverse Abel transformation (IAT) from measured 2D images projected\u003cbr /\u003eon a position-sensitive detector(PSD) to the cross- sectional images in the\u003cbr /\u003eperpendicular plane of the spectrometer. Using the speed distributions extracted\u003cbr /\u003eperpendicular plane of the spectrometer. Using the speed distributions extracted\u003cbr /\u003efrom these cross-sectional images, we have evaluated the temperatures by the\u003cbr /\u003eleast-squares fit of the data points to the Maxwell-Boltzmann distribution. The\u003cbr /\u003ebest fitted curves of the lighter three rare gases are in reasonable agreement\u003cbr /\u003ewith the Maxwell-Boltzmann distributions at the temperature \u003ci\u003eT\u003c/i\u003e= 300K. The\u003cbr /\u003etemperatures obtained by the fittings are 282,272 and 295 K for He, Ne ard Ar, \u003cbr /\u003erespectively. Small deviations from the expected value of 300 K can be\u003cbr /\u003eaccounted for by systematic errors peculiar to the numerical image processing in\u003cbr /\u003ethe IAT. For Kr and Xe the agreement is much worse mainly due to smaller\u003cbr /\u003esignal-to-background ratios. Furthermore, the best fitted curve of Xe appears to\u003cbr /\u003eshift by 60 K in the direction of lower speed as compared to the expected\u003cbr /\u003edistribution at 300 K. This shift can be explained as that the raw images of Xe\u003cbr /\u003eincludes not only Xe\u003csup\u003e+\u003c/sup\u003e but also Xe\u003csup\u003e2+\u003c/sup\u003e signal counts.\u003cbr /\u003e　　We have simulated the images of five rare gases at 300 K to compare with\u003cbr /\u003ethe experimentally obtained images. From the simulated projections on the PSD\u003cbr /\u003ewe have obtained the cross-sectional images and speed distributions. The\u003cbr /\u003etemperature of He is evaluated to be 287 K from the last-squares fit of the data\u003cbr /\u003epoints of the simulated speed distribution to the Maxwell-Boltzmann\u003cbr /\u003edistribution. Similar simulations were executed for Ne and Ar. All the\u003cbr /\u003etemperatures were found to be in good agreement with those from the\u003cbr /\u003eexperimental images. Moreover, a close inspection of the simulated images\u003cbr /\u003erevealed that the defocusing effect due to a definite ionization volume can be\u003cbr /\u003e well reproduced by introducing two Gaussian functions as (a) 2\u0026sigma;\u003csmall\u003ex\u003c/small\u003e, = 0.2 and \u003cbr /\u003e2\u0026sigma;\u003csmall\u003ey\u003c/small\u003e= 2.8 mm when oven with thickness monitor was not installed inside the\u003cbr /\u003eexperimental vacuum chamber, \u003csmall\u003e(b)\u003c/small\u003e2\u0026sigma;, \u003csmall\u003ex\u003c/small\u003e=1.7 and 2 \u0026sigma; \u003csmall\u003ey\u003c/small\u003e=3.2mm when oven\u003cbr /\u003ewith thickness monitor was installed. Here, \u0026sigma; \u003csmall\u003ex\u003c/small\u003e and \u0026sigma; \u003csmall\u003ey\u003c/small\u003e are corresponding to the \u003cbr /\u003estandard deviations of two Gaussian functions which are called defocusing\u003cbr /\u003e parameters.\u003cbr /\u003e　　　A novel simulation method has been established for the image of the 3D\u003cbr /\u003evelocity distributions of C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e produced by dissociative photoionization of C\u003csmall\u003e60-\u003c/small\u003e.\u003cbr /\u003eWe calculated the arrival positions of C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e ions, the spatial density functions, \u003cbr /\u003eand the projections on the PSD. The 2D cross-sectional images were derived\u003cbr /\u003e from the projected images of C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e ions produced through the stepwise C\u003csmall\u003e2-\u003c/small\u003e and\u003cbr /\u003eC\u003csmall\u003e4-\u003c/small\u003e-loss processes. At \u003ci\u003eT\u003c/i\u003e= 0 K a marked difference in the image pattern could be\u003cbr /\u003eseen between the two processes but it is almost smeared out under bulk\u003cbr /\u003econditions of C\u003csmall\u003e60\u003c/small\u003e at \u003ci\u003eT\u003c/i\u003e= \u003ci\u003e273\u003c/i\u003eK owing to the convolution of the thermal velocity\u003cbr /\u003eof nascent parent C\u003csmall\u003e60\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e ions. In contrast, a remarkable difference at \u003ci\u003eT\u003c/i\u003e=0 K were\u003cbr /\u003efound to remain event at \u003ci\u003e T\u003c/i\u003e=785K for the C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003eformation in the C\u003csmall\u003e60\u003c/small\u003e beams, \u003cbr /\u003e because the transverse velocity of the beam is extremely low. The difference in\u003cbr /\u003ethe image pattern between the two processes permits conclusive\u003cbr /\u003eevidence on which mechanism dominates photofragmentation of C\u003csmall\u003e60\u003c/small\u003e in the\u003cbr /\u003eextreme UV region. We therefore consider that the present VMI spectrometer\u003cbr /\u003ewill be available for future studies of the excited-state dynamics of fullerene\u003cbr /\u003eions. Experimentally the image of C\u003csmall\u003e56\u003c/small\u003e\u003csup\u003e+\u003c/sup\u003e might be contaminated by the\u003cbr /\u003ebackground dark counts due to impurities such as water, air, and organic\u003cbr /\u003ecompounds. We have tried to remove the background counts from the measured\u003cbr /\u003e2D image by means of deconvolution using the low-pass and Wiener filters.", "subitem_description_type": "Other"}]}, "item_1_description_18": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_description": "application/pdf", "subitem_description_type": "Other"}]}, "item_1_description_7": {"attribute_name": "学位記番号", "attribute_value_mlt": [{"subitem_description": "総研大甲第1217号", "subitem_description_type": "Other"}]}, "item_1_select_14": {"attribute_name": "所蔵", "attribute_value_mlt": [{"subitem_select_item": "有"}]}, "item_1_select_16": {"attribute_name": "複写", "attribute_value_mlt": [{"subitem_select_item": "複写不可"}]}, "item_1_select_17": {"attribute_name": "公開状況", "attribute_value_mlt": [{"subitem_select_item": "全文公開可"}]}, "item_1_select_8": {"attribute_name": "研究科", "attribute_value_mlt": [{"subitem_select_item": "物理科学研究科"}]}, "item_1_select_9": {"attribute_name": "専攻", "attribute_value_mlt": [{"subitem_select_item": "07 構造分子科学専攻"}]}, "item_1_text_10": {"attribute_name": "学位授与年度", "attribute_value_mlt": [{"subitem_text_value": "2008"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "Md., Serajul Islam Prodhan", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_files": {"attribute_name": "ファイル情報", "attribute_type": "file", "attribute_value_mlt": [{"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 0, "filename": "甲1217_要旨.pdf", "filesize": [{"value": "294.7 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 294700.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/1461/files/甲1217_要旨.pdf"}, "version_id": "78475b7f-a908-405b-aa61-e1cca8663795"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 1, "filename": "甲1217_本文.pdf", "filesize": [{"value": "1.9 MB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 1900000.0, "url": {"label": "本文", "url": "https://ir.soken.ac.jp/record/1461/files/甲1217_本文.pdf"}, "version_id": "e0b79e1f-e587-4767-b3c4-f99a2d7dd676"}]}, "item_language": {"attribute_name": "言語", "attribute_value_mlt": [{"subitem_language": "eng"}]}, "item_resource_type": {"attribute_name": "資源タイプ", "attribute_value_mlt": [{"resourcetype": "thesis", "resourceuri": "http://purl.org/coar/resource_type/c_46ec"}]}, "item_title": "Construction of a Velocity Map Imaging Apparatus and its Application to a Study of Photoionization Processes of C60", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "Construction of a Velocity Map Imaging Apparatus and its Application to a Study of Photoionization Processes of C60"}, {"subitem_title": "Construction of a Velocity Map Imaging Apparatus and its Application to a Study of Photoionization Processes of C60", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "21", "path": ["9"], "permalink_uri": "https://ir.soken.ac.jp/records/1461", "pubdate": {"attribute_name": "公開日", "attribute_value": "2010-03-25"}, "publish_date": "2010-03-25", "publish_status": "0", "recid": "1461", "relation": {}, "relation_version_is_last": true, "title": ["Construction of a Velocity Map Imaging Apparatus and its Application to a Study of Photoionization Processes of C60"], "weko_shared_id": -1}