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Note on the energy of the isometric transition in 109Ag
Nuclear Physics A104 (1967) 511--512; (~) North-ltolland Publishin,q Co., Amsterdam Not to be reproduced by photoprint or microfilm wahout written permission from the publisher
NOTE ON THE ENERGY OF THE ISOMERIC TRANSITION IN l°gAg W I L L I A M R. P I E R S O N and R I C H A R D
H. M A R S H
Scientific Research Staff, Ford Motor Company, Dearborn, Michlqan, USA Received 10 July 1967 T h e energy o f the g a m m a ray emitted during the isomeric transition m 1°gAg was determined, relatlve to energies o f g a m m a rays emitted in ~S2Ta decay, w~th a h t h m m - d r f f t e d silicon detector and ~ZTa a n d ~°gCd sources. Referred to the 84678 eV h n e m ~s~l'a decay, the ~someric transition energy is 3354 7 + 30 cV higher, or (subject to the energy a s s u m e d for the 84678 eV hne) 88033 eV all together.
Abstract:
E I
R A D I O A C T I V I T Y 1°9Cd, ~sZra; m e a s u r e d E;,. Sl(Li) detector.
I
The decay of 1.2 y 1 0 9 C d gives rise to a 88 keV gamma ray (the isomeric transition of 40 sec 109Ag ) which finds widespread use in gamma-ray spectroscopy. The energy of the transition has been reported as 89.0+0.5 keV [ref. i)], 87.5 keV [ref. 2)], 87.9 keV [ref. 3)], 87.5_+0.8 keV [ref. 4)] and 87.7_+0.2 keV [ref. 5)]. In 1965, Dingus and Talbert 6) showed by a critical-absorption experiment that the correct value actually must lie somewhere between the K absorption edges of lead and bismuth (or, if the binding-energy tabulation of ref. 7) is followed, between 88.006 and 90.527 keV). Since all but one of the previously-reported values fell outside this range, and since in any case the correct value is rather poorly known for a gamma ray in such common use, we felt that a measurement with a lithium-drifted silicon detector would be appropriate. The system on which our measurements were performed consists in part of a cooled l cm diam Si(Li) crystal of sensitive depth approximately 3 mm and a cooledinput-FET preamplifier t. The preamplifier output was taken to a RIDL 30-12B 400-channel analyser via a RIDL 30-16 amplifier. The resolution of this system ( F W H M ) for iron K X-rays is about 600 eV. The system was calibrated by means of four lines, all in the decay of ~82Ta; they are given by Gruber etal. 8) as 31735.1_+ 1 ( - y,), 67747.9_+2(72), 84678.3+_3(y3) , and 100101.5_+2 eV()~4). Spectra of ~82Ta and 1 ° 9 C d w e r e taken concurrently. Linear calibration curves were constructed using (i) 73 and Y4 and (ii) Y2, Y3 and V4. Similarly, quadratic curves using (i) Yl, V3 and Y4, (ii) "/2, 7a and 74 and (iii) all four lines were constructed. From each of these five curves we obtained a value of A, the * Purchased from Technical M e a s u r e m e n t s Corp. 511
512
W . R. PIERSON A N D R. H. MARSH
energy difference between the g a m m a ray in question and ?3. The process was repeated at a different amplifier gain in order to compensate somewhat for system nonlinearities. It was also verified that the g a m m a spectral shapes from 182Ta and 1°9Cd were such that the peak positions read for ?3 and the g a m m a ray in question were not appreciably perturbed by interference from each other or from other g a m m a rays in the composite spectrum. The result obtained in the above experiments is A = 3354.7__.6.3 eV, the error shown being the root-mean-square precision. The t o t a l uncertainty (accuracy) in A is estimated as 0-4 ~ 30 eV. The energy of the g a m m a ray in question is thus specified in such a way that it can be revised at any time that the estimate for the energy of ?3 is revised. The ?3 energy given above 8) would imply for the g a m m a ray in 109Cd decay an energy of 88033 eV, consistent with the K-absorption-edge experiments of ref. 6). We saw a number of the k n o w n 9) g a m m a rays from the decay of 182Ta. However, the 33.6 keV line reported by Murray et al. 1o) is absent.
References 1) 2) 3) 4) 5) 6) 7)
H. Bradt et al., Helv. Phys. Acta 20 (1947) 153 J. M. Cork et al., Phys. Rev. 79 (1950) 938 F. A. Johnson, Can. J. Phys. 31 (1953) 1136 A. H. Wapstra, Ark. Fys. 7 (1954) 265 J. Moreau, J. Phys. Rad. 15 (1954) 380 R. S. Dingus and W. L. Talbert, Jr., Nuclear Physics 74 (1965) 110 S. Hagstrom et al., in Alpha-, beta-, and gamma-ray spectroscopy, Vol. 1, ed. by K. Siegbahn (North-Holland Publ. Co., Amstcrdam, 1965) app. 2 8) U. Gruber et al., Z. Naturf. 20a (1965) 929 9) K. Way, Nucl. Data 1B (1966) BI-I-I 10) J. J. Murray et al., Phys. Rex'. 97 (1955) 1007
NOTE ON THE ENERGY OF THE ISOMERIC TRANSITION IN l°gAg W I L L I A M R. P I E R S O N and R I C H A R D
H. M A R S H
Scientific Research Staff, Ford Motor Company, Dearborn, Michlqan, USA Received 10 July 1967 T h e energy o f the g a m m a ray emitted during the isomeric transition m 1°gAg was determined, relatlve to energies o f g a m m a rays emitted in ~S2Ta decay, w~th a h t h m m - d r f f t e d silicon detector and ~ZTa a n d ~°gCd sources. Referred to the 84678 eV h n e m ~s~l'a decay, the ~someric transition energy is 3354 7 + 30 cV higher, or (subject to the energy a s s u m e d for the 84678 eV hne) 88033 eV all together.
Abstract:
E I
R A D I O A C T I V I T Y 1°9Cd, ~sZra; m e a s u r e d E;,. Sl(Li) detector.
I
The decay of 1.2 y 1 0 9 C d gives rise to a 88 keV gamma ray (the isomeric transition of 40 sec 109Ag ) which finds widespread use in gamma-ray spectroscopy. The energy of the transition has been reported as 89.0+0.5 keV [ref. i)], 87.5 keV [ref. 2)], 87.9 keV [ref. 3)], 87.5_+0.8 keV [ref. 4)] and 87.7_+0.2 keV [ref. 5)]. In 1965, Dingus and Talbert 6) showed by a critical-absorption experiment that the correct value actually must lie somewhere between the K absorption edges of lead and bismuth (or, if the binding-energy tabulation of ref. 7) is followed, between 88.006 and 90.527 keV). Since all but one of the previously-reported values fell outside this range, and since in any case the correct value is rather poorly known for a gamma ray in such common use, we felt that a measurement with a lithium-drifted silicon detector would be appropriate. The system on which our measurements were performed consists in part of a cooled l cm diam Si(Li) crystal of sensitive depth approximately 3 mm and a cooledinput-FET preamplifier t. The preamplifier output was taken to a RIDL 30-12B 400-channel analyser via a RIDL 30-16 amplifier. The resolution of this system ( F W H M ) for iron K X-rays is about 600 eV. The system was calibrated by means of four lines, all in the decay of ~82Ta; they are given by Gruber etal. 8) as 31735.1_+ 1 ( - y,), 67747.9_+2(72), 84678.3+_3(y3) , and 100101.5_+2 eV()~4). Spectra of ~82Ta and 1 ° 9 C d w e r e taken concurrently. Linear calibration curves were constructed using (i) 73 and Y4 and (ii) Y2, Y3 and V4. Similarly, quadratic curves using (i) Yl, V3 and Y4, (ii) "/2, 7a and 74 and (iii) all four lines were constructed. From each of these five curves we obtained a value of A, the * Purchased from Technical M e a s u r e m e n t s Corp. 511
512
W . R. PIERSON A N D R. H. MARSH
energy difference between the g a m m a ray in question and ?3. The process was repeated at a different amplifier gain in order to compensate somewhat for system nonlinearities. It was also verified that the g a m m a spectral shapes from 182Ta and 1°9Cd were such that the peak positions read for ?3 and the g a m m a ray in question were not appreciably perturbed by interference from each other or from other g a m m a rays in the composite spectrum. The result obtained in the above experiments is A = 3354.7__.6.3 eV, the error shown being the root-mean-square precision. The t o t a l uncertainty (accuracy) in A is estimated as 0-4 ~ 30 eV. The energy of the g a m m a ray in question is thus specified in such a way that it can be revised at any time that the estimate for the energy of ?3 is revised. The ?3 energy given above 8) would imply for the g a m m a ray in 109Cd decay an energy of 88033 eV, consistent with the K-absorption-edge experiments of ref. 6). We saw a number of the k n o w n 9) g a m m a rays from the decay of 182Ta. However, the 33.6 keV line reported by Murray et al. 1o) is absent.
References 1) 2) 3) 4) 5) 6) 7)
H. Bradt et al., Helv. Phys. Acta 20 (1947) 153 J. M. Cork et al., Phys. Rev. 79 (1950) 938 F. A. Johnson, Can. J. Phys. 31 (1953) 1136 A. H. Wapstra, Ark. Fys. 7 (1954) 265 J. Moreau, J. Phys. Rad. 15 (1954) 380 R. S. Dingus and W. L. Talbert, Jr., Nuclear Physics 74 (1965) 110 S. Hagstrom et al., in Alpha-, beta-, and gamma-ray spectroscopy, Vol. 1, ed. by K. Siegbahn (North-Holland Publ. Co., Amstcrdam, 1965) app. 2 8) U. Gruber et al., Z. Naturf. 20a (1965) 929 9) K. Way, Nucl. Data 1B (1966) BI-I-I 10) J. J. Murray et al., Phys. Rex'. 97 (1955) 1007