Depth and size dependence of 53Mn activity in chondrites

Bhattacharya, S. K. ; Imamura, M. ; Sinha, N. ; Bhandari, N. (1980) Depth and size dependence of 53Mn activity in chondrites Earth and Planetary Science Letters, 51 (1). pp. 45-57. ISSN 0012-821X

PDF - Publisher Version

Official URL:

Related URL:


The cosmogenic 53Mn activity was measured in samples from cores of four chondrites, Madhipura, Udaipur, Bansur and St. Severin. A simultaneous study of cosmic ray tracks established the pre-atmospheric size of these meteorites and the shielding depth of the samples. The four chondrites are found to have had effective radii, RE, of 6.5, 9, 15 and 25 cm, respectively, in space. The experimental depth profiles of the 53Mn activity indicate that, (1) the production rate, at any given depth, increases with size of the meteorite up to RE ~25cm; (2) the activity profile for RE~15cm is nearly flat for shielding depths greater than 3 cm, the increase being less than 10%; and (3) for RE ~25cm the increase from the near-surface region to the centre is about 40% indicating that the cascade of secondaries becomes very important for RE > 15cm. These profiles are used to determine the spectral hardness parameter, α, as a function of depth in the meteoroid which, in turn, can be used to calculate the production profiles of other low-energy nuclides. Calculations for 26Al show agreement with observations within 20%.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
ID Code:18491
Deposited On:17 Nov 2010 09:04
Last Modified:17 May 2016 03:12

Repository Staff Only: item control page