HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD
The density of ice cores is one of the fundamental quantities in ice core studies. In order to clarify the densification and close-off processes at a drilling site, a depth profile of the densities has been measured by the conventional volumetric method. However, the method requires laborious work a...
Main Authors: | , , , , , |
---|---|
Format: | Report |
Language: | English |
Published: |
ABSTRACT
1997
|
Subjects: | |
Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3999 http://id.nii.ac.jp/1291/00003999/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3999&item_no=1&attribute_id=18&file_no=1 |
id |
ftnipr:oai:nipr.repo.nii.ac.jp:00003999 |
---|---|
record_format |
openpolar |
spelling |
ftnipr:oai:nipr.repo.nii.ac.jp:00003999 2023-05-15T16:38:56+02:00 HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD タユキ カズシゲ ホンドウ タケオ ナリタ ヒデキ Kazushige TAYUKI Takeo HONDOH Hideki NARITA 1997-11 https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3999 http://id.nii.ac.jp/1291/00003999/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3999&item_no=1&attribute_id=18&file_no=1 en eng ABSTRACT Institute of Low Temperature Science, Hokkaido University National Institute of Polar Research https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3999 http://id.nii.ac.jp/1291/00003999/ AA10756213 Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 253(1997-11) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3999&item_no=1&attribute_id=18&file_no=1 Departmental Bulletin Paper P(論文) 1997 ftnipr 2023-01-14T19:56:31Z The density of ice cores is one of the fundamental quantities in ice core studies. In order to clarify the densification and close-off processes at a drilling site, a depth profile of the densities has been measured by the conventional volumetric method. However, the method requires laborious work and time consuming procedures. In addition, the method itself has a drawback in depth resolution, because it also requires a large volume of sample. Since density variations with much shorter wavelengths than the resolution of the method have been suggested by optical observations of ice cores, it has been desired to develop a new method with higher depth resolution. In the present study, we aim to apply the X-ray absorption method for this purpose. From the view point of the X-ray absorption method, an ice core is a material composed of pure ice and pores, and small amounts of impurities included in ice can be neglected. Accordingly, transparent X-ray intensities depend only on the densities of the ice cores. The ice core samples were prepared with a microtome knife so that a long bar sample has two parallel flat surfaces. The profile of transmitted X-ray intensities directly measured was converted to that of densities, using a calibration curve for transmitted intensities against various thicknesses of pure bulk ice. The depth resolution of the present method is 1mm in these preliminary measurements. Taking account of statistical errors in X-ray intensity measurement and fluctuations of the sample thickness along the sample axis, the error included in each data point of the density profile is about 1%. In order to obtain high sensitivity to density variations, the X-ray generator was operated at low voltage below 30kV. A two dimensional detector of X-rays, the Imaging Plate, was also used for observing layer structures of the ice cores. The intensity measurement takes only about 5min for a sample with a length of 500mm. Such a very quick measurement can be achieved by a strong X-ray generator, Rigaku RU-300,installed ... Report ice core Polar meteorology and glaciology Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology National Institute of Polar Research Repository, Japan |
institution |
Open Polar |
collection |
National Institute of Polar Research Repository, Japan |
op_collection_id |
ftnipr |
language |
English |
description |
The density of ice cores is one of the fundamental quantities in ice core studies. In order to clarify the densification and close-off processes at a drilling site, a depth profile of the densities has been measured by the conventional volumetric method. However, the method requires laborious work and time consuming procedures. In addition, the method itself has a drawback in depth resolution, because it also requires a large volume of sample. Since density variations with much shorter wavelengths than the resolution of the method have been suggested by optical observations of ice cores, it has been desired to develop a new method with higher depth resolution. In the present study, we aim to apply the X-ray absorption method for this purpose. From the view point of the X-ray absorption method, an ice core is a material composed of pure ice and pores, and small amounts of impurities included in ice can be neglected. Accordingly, transparent X-ray intensities depend only on the densities of the ice cores. The ice core samples were prepared with a microtome knife so that a long bar sample has two parallel flat surfaces. The profile of transmitted X-ray intensities directly measured was converted to that of densities, using a calibration curve for transmitted intensities against various thicknesses of pure bulk ice. The depth resolution of the present method is 1mm in these preliminary measurements. Taking account of statistical errors in X-ray intensity measurement and fluctuations of the sample thickness along the sample axis, the error included in each data point of the density profile is about 1%. In order to obtain high sensitivity to density variations, the X-ray generator was operated at low voltage below 30kV. A two dimensional detector of X-rays, the Imaging Plate, was also used for observing layer structures of the ice cores. The intensity measurement takes only about 5min for a sample with a length of 500mm. Such a very quick measurement can be achieved by a strong X-ray generator, Rigaku RU-300,installed ... |
format |
Report |
author |
タユキ カズシゲ ホンドウ タケオ ナリタ ヒデキ Kazushige TAYUKI Takeo HONDOH Hideki NARITA |
spellingShingle |
タユキ カズシゲ ホンドウ タケオ ナリタ ヒデキ Kazushige TAYUKI Takeo HONDOH Hideki NARITA HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
author_facet |
タユキ カズシゲ ホンドウ タケオ ナリタ ヒデキ Kazushige TAYUKI Takeo HONDOH Hideki NARITA |
author_sort |
タユキ カズシゲ |
title |
HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
title_short |
HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
title_full |
HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
title_fullStr |
HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
title_full_unstemmed |
HIGH RESOLUTION DENSITY PROFILE OF ICE CORES MEASURED BY A NEW X-RAY METHOD |
title_sort |
high resolution density profile of ice cores measured by a new x-ray method |
publisher |
ABSTRACT |
publishDate |
1997 |
url |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3999 http://id.nii.ac.jp/1291/00003999/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3999&item_no=1&attribute_id=18&file_no=1 |
genre |
ice core Polar meteorology and glaciology Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology |
genre_facet |
ice core Polar meteorology and glaciology Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology |
op_relation |
https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3999 http://id.nii.ac.jp/1291/00003999/ AA10756213 Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 253(1997-11) https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3999&item_no=1&attribute_id=18&file_no=1 |
_version_ |
1766029287302889472 |