The response and calibration of thin Si DE detectors Yanwen Zhang, Thomas Winzell, Harry J. Whitlow * Department of Nuclear Physics, Lund Institute of Technology, Box 118, S-22100 Lund, Sweden Received 23 February 1999; received in revised form 8 June 1999 Abstract The response of thin (7 lm) self-supporting Si p-i-n DE detectors for light recoils (Z 6 8) has been characterised using a conventional Elastic Recoil Detection (ERD) set-up. In this study, the energy loss of each recoil in the DE detector was measured by determining the incident energy from the time of ¯ight and the energy after traversing the DE detector using a thick (280 lm) Si p-i-n diode E detector. 40 MeV 35 Cl 7 ions were used to produce recoils of H, Li, Be, B, C, N and O. Correlation of the energy loss in the DE detector with the amplitude of the DE signals was used to assign calibration constants. Analysis of the variance of the signals from the trend line revealed that the standard deviation of the data perpendicular to the trend line which is not contributed to by energy straggling and multiple scattering, in- creases with increasing recoil atomic number. Ó 1999 Elsevier Science B.V. All rights reserved. PACS: 29.40.Wk; 34.50.Bw; 61.85.-p; 07.77.Ko; 82.80.Yc Keywords: DE detectors; Elastic Recoil Detection (ERD); Time of ¯ight; Energy loss; p-i-n diodes 1. Introduction Elastic Recoil Detection (ERD) using DE±E detector telescopes has recently attracted atten- tion. Although gas ionisation [1±17] detectors have found widest application up till now, increasing interest is being focused on Si semiconductor DE detectors [18±24]. This is coupled with the devel- opment of technology that permits eective pro- cessing of thin Si detectors [25±28] in large batches [29]. Gas ionisation detectors have the advantage that the thickness of detector can be varied by changing the gas pressure, and it is possible to use special electrode forms, such as the saw-tooth ge- ometry [11,17], to determine a correction for ki- nematic spreading with large detector solid angles. However, gas detectors are physically large, have a high energy threshold and energy resolution as- sociated with the energy loss and straggling in the entrance window. The Si detectors are physically small with thin (1 lm) entrance windows, more compatible with Ultra High Vacuum (UHV) technology, and do not require a complex and expensive gas handling system. Although Si p-i-n detectors are susceptible to radiation damage, this can be almost completely recovered by a mild 150°C heat treatment [30]. Nuclear Instruments and Methods in Physics Research B 159 (1999) 101±110 www.elsevier.nl/locate/nimb * Corresponding author. Tel.: +46-46-222-7630; fax: +46-46- 222-4709; e-mail: harry_j.whitlow@nuclear.lu.se 0168-583X/99/$ - see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 9 ) 0 0 5 1 8 - 2