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70. Study of the energy spectrum of protons emitted in he (n, p)-reaction on 27Al with 14 MeV neutrons
1158
ABSTRACTS
used by L e v i n s o n and F o r d 2) in their s t u d y of the same nuclei. Further experiments and analysis could yield information about the T = 0 interaction. 1) B o e k e l m a n , C. K., B r a a m s , C. M., B u e c h n e r , W. W., Guthe,lD.]B. and S p e r d u t o , A. (to be published). 2) L e v i n s o n , C. and Ford, K. W., Phys. Rev. 1 0 0 (1955) 13.
IId. MISCELLANEOUS
REACTIONS
69. R 6 a c t i o n taO(p, n) lSF et n i v e a u d u f l u o r 18. V. ~N~AGGIAR, D. SZTEINSZNAIDER e t J. THIRION.
M. ROCLAWSKI-CONJEAUD,
Service de Physique nucl6aire, Centre d'I~tudes nucl6aires, Saclay, France. Les niveaux excit6s du fluor 18 ont 6t6 recherch6s pax la r6action 180 (p, n) 18F. L'6tude des seuils de neutrons lents de cette r6action compl6t6e par la mesure des rayons gamma correspondants donne deux niveaux certains k 1050 keV et 950 keV. Si on se limite aux valeurs de spin 0-b, 3-[-, 5q- pr6vues par E l l i o t t et F l o w e r s , le niveau situ6 ~ 1050 keV a u n spin 0 + car la transition gamma correspondante a une vie inf6rieure h 3.10 -13 s (Effet Doppler observable dans une cible de glace mince d6pos6e sur du plomb). Le niveau situ6 ~ 950 keV a un spin 3-}- ou 5-~- (pas d'effet Doppler observable).
70. S t u d y of t h e e n e r g y s p e c t r u m of p r o t o n s e m i t t e d i n h e (n, p ) - r e a c t i o n o n 27A1 w i t h 14 MeV n e u t r o n s . L. COLLI and U. FACCHINI. Laboratori C.I.S.E., Milano, Italia. An apparatus consisting of a proportional counter and a scintillation spectrometer ~or the detection of spectra of protons emitted"by neutrons in (n, p) reactions on various target nuclei is described. The acceptance solid angle corresponds to protons emitted forward with angles between 0 and 50 degrees. A discussion of the behaviour of the instrument and preliminary results on proton spectra, particularly regarding the reaction 27Al(n, p)27Mg with 14 MeV neutrons axe presentod. Results for Cu, Zn, Mg and Si are also presented.
71. P r o t o n s f r o m t h e i n t e r a c t i o n of 14 M e V n e u t r o n s w i t h m e d i u m w e i g h t n u c l e i . D. L. ALLEN. Atomic Energy Research Establishment, Harwell, England. The energies of the protons emitted by 27A1, 54Fe, 5SFe, SSNi, SONi, 63Cu and ssCu when bombarded by 14 MeV neutrons have been measured using a photographic plate method. I n addition, the angular distribution of the protons emitted by s3Cu has been measured. The energy distributions show that the protons are produced b y the three processes: {n, p) compound nucleus, (n, np) compound nucleus and (n, p) direct interaction. Rough cross-sections for these processes are given. I n nuclei in which the neutron and proton binding energies are favourable, the magnitude of the (n, np) cross-section exceeds 200 mb. Comparison with the statistical theory shows that the cross-section for the reactions proceeding via ~ compound nucleus depends strongly on whether the target nucleus is of even-even or of odd-even type.
ABSTRACTS
used by L e v i n s o n and F o r d 2) in their s t u d y of the same nuclei. Further experiments and analysis could yield information about the T = 0 interaction. 1) B o e k e l m a n , C. K., B r a a m s , C. M., B u e c h n e r , W. W., Guthe,lD.]B. and S p e r d u t o , A. (to be published). 2) L e v i n s o n , C. and Ford, K. W., Phys. Rev. 1 0 0 (1955) 13.
IId. MISCELLANEOUS
REACTIONS
69. R 6 a c t i o n taO(p, n) lSF et n i v e a u d u f l u o r 18. V. ~N~AGGIAR, D. SZTEINSZNAIDER e t J. THIRION.
M. ROCLAWSKI-CONJEAUD,
Service de Physique nucl6aire, Centre d'I~tudes nucl6aires, Saclay, France. Les niveaux excit6s du fluor 18 ont 6t6 recherch6s pax la r6action 180 (p, n) 18F. L'6tude des seuils de neutrons lents de cette r6action compl6t6e par la mesure des rayons gamma correspondants donne deux niveaux certains k 1050 keV et 950 keV. Si on se limite aux valeurs de spin 0-b, 3-[-, 5q- pr6vues par E l l i o t t et F l o w e r s , le niveau situ6 ~ 1050 keV a u n spin 0 + car la transition gamma correspondante a une vie inf6rieure h 3.10 -13 s (Effet Doppler observable dans une cible de glace mince d6pos6e sur du plomb). Le niveau situ6 ~ 950 keV a un spin 3-}- ou 5-~- (pas d'effet Doppler observable).
70. S t u d y of t h e e n e r g y s p e c t r u m of p r o t o n s e m i t t e d i n h e (n, p ) - r e a c t i o n o n 27A1 w i t h 14 MeV n e u t r o n s . L. COLLI and U. FACCHINI. Laboratori C.I.S.E., Milano, Italia. An apparatus consisting of a proportional counter and a scintillation spectrometer ~or the detection of spectra of protons emitted"by neutrons in (n, p) reactions on various target nuclei is described. The acceptance solid angle corresponds to protons emitted forward with angles between 0 and 50 degrees. A discussion of the behaviour of the instrument and preliminary results on proton spectra, particularly regarding the reaction 27Al(n, p)27Mg with 14 MeV neutrons axe presentod. Results for Cu, Zn, Mg and Si are also presented.
71. P r o t o n s f r o m t h e i n t e r a c t i o n of 14 M e V n e u t r o n s w i t h m e d i u m w e i g h t n u c l e i . D. L. ALLEN. Atomic Energy Research Establishment, Harwell, England. The energies of the protons emitted by 27A1, 54Fe, 5SFe, SSNi, SONi, 63Cu and ssCu when bombarded by 14 MeV neutrons have been measured using a photographic plate method. I n addition, the angular distribution of the protons emitted by s3Cu has been measured. The energy distributions show that the protons are produced b y the three processes: {n, p) compound nucleus, (n, np) compound nucleus and (n, p) direct interaction. Rough cross-sections for these processes are given. I n nuclei in which the neutron and proton binding energies are favourable, the magnitude of the (n, np) cross-section exceeds 200 mb. Comparison with the statistical theory shows that the cross-section for the reactions proceeding via ~ compound nucleus depends strongly on whether the target nucleus is of even-even or of odd-even type.