1995 Fiscal Year Final Research Report Summary
OVERLAPPING EFFECTS OF CASCADE DAMAGE AS STUDIED BY IN-SUTU OBSERVATION UNDER HEAVY ION IRRADIATION
| Project/Area Number |
06452426
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
エネルギー学一般・原子力学
|
|---|
| Research Institution | THE UNIVERSITY OF TOKYO |
|---|
Principal Investigator |
SEKIMURA Naoto THE UNIVERSITY OF TOKYO,SCHOOL OF ENGINEERING,ASSOCIATE PROFESSOR, 大学院・工学系研究科, 助教授 (10183055)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWATA Shuichi THE UNIVERSITY OF TOKYO,RESEARCH INTO ARTIFACT CENTER PROFESSOR, 教授 (50124665)
ISHINO Shiori TOKAI UNIVERSITY FACULITY OF ENGINEERING,PROFESSOR, 工学部, 教授 (70010733)
KAWANISHI Hiroshi THE UNIVERSITY OF TOKYO,SCHOOL OF ENGINEERING,RESEARCH ASSOCIATE, 大学院・工学系研究科, 助手 (40010970)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | HEAVY ION IRRADIATION / CASCADE DAMAGE / DEFECT CLUSTERS / PRIMARY KNOCK-ON ATOM / OVERLAPPING EFFECTS |
|---|
| Research Abstract |
Cascade damage from a energetic primary knock-on atom(PKA)in an irradiated materials produces high density of displacement damage, which can results in the direct formation of defect cluster at the core of the cascade.Higher dose irradiation is considered to cause overlapping of cascade damage, however this overlapping and resultant defect cluster formation is dependent on PKA energy, because suze of cascade damage is also strongly dependent on PKA energy.By comparing data from 21 MeV self-ion irradiation, fission neutron irradiation and 14 MeV neutron irradiation to thin foils of gold, it was found that cascade damage from PKA's higher than 165 KeV were effective for the production of new vacancy clusters by the overlapping of cascade damage. The formation of new vacancy clusters can be divided into the following 2 processes ; the formation of invisible vacancy agglomeration for a PKA,and their conversion of visible clusters by the near-by cascades. To clarify these processes, successive self-ion irradiation experiments with different energies were performed using a 400 keV heavy ion accelerator. Dose dependence of vacancy clusters in thin foils of gold was found to be strongly dependent on energy of self-ions. High energy PKA is found to produce 3 dimensional distributions of sub-cascades and some of them remains as invisible clusters. They can only be converted to cisible vlusters by self-ions higher than 200 keV in the case of thin foils of gold. Futher experiments are conducted in the YAYOI rector to verify these results under neutron irradiation in which PKA energy has distribution
|
