BA Level Research Articles

Efficient frequency conversion of ultrashort pulses from the visible (0.55 μ) to the infrared (1.5 μ) in barium vapor

The frequency of ?p?0.55 ? radiation of ultrashort duration was converted to the infrared (? =1.5 ?) in Ba vapor in the presence of an Ar buffer gas whose pressure was varied between 1 and 300 Torr. The conversion quantum efficiency was 30%. An investigation was made of the mechanisms for population of the 1P10 Ba level. It was found that when the detuning of the pump radiation from the appropriate transition was large, the only mechanism for population of the 1P10 level (followed by lasing at ? =1.5 ?) was optical collisions: Ba(1S0)+Ar+h?p?Ba(1P10)+Ar. For small detunings and low Ar pressures other mechanisms for population of the 1P10 level were also found. Measurements were made of the temporal characteristics of the ? =1.5 ? radiation. Possible reasons for the absence of electronic stimulated Raman scattering are discussed.

Nuclear data sheets for A = 139

The 1966 version of the Nuclear Data Sheets has been revised according to experimental data received prior to January 1974, including approximately 150 papers. Data are presented for 11 nuclei (I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, and Eu). No decay schemes are available for the ground-state decay of I, Pm, Sm, or Eu, and no excited states or gamma transitions have been definitely assigned to I, Xe, Pm, or Eu. The Xe and Cs decay schemes have been extensively studied; however, no J π assignments are available for the 50 excited states of Cs because of the lack of gamma multipolarity assignments and no J π assignment for the Xe ground state. The Ba level scheme includes about 100 levels with about 43 J π assignments because of the extensive Cs decay, (n, γ), and (d,p) data. The La level scheme includes about 80 levels with about 27 J π assignments. More detailed J π assignments cannot be made primarily because of the lack of gamma multipolarity data or definitive l-values in reaction data. About 28 levels have been assigned to Ce with only 17 J π assignments, again primarily because of the lack of gamma multipolarities. Pr has been assigned 30 levels with 24 J π values. Rather extensive gamma multipolarities (35) are assigned in Pr. Only 6 levels have been placed in Nd, with J π assignments for only the ground state (29.7 m) and isomer (5.5 h), the other four levels being due to (α,xn γ) data. Four levels are suggested in Sm from the 9.5-s isomer internal gamma decay to the ground state (2.6 m), although no J π values are known since no gamma multipolarities are known and no decay scheme is available for the ground state.

Test Retest Reliability and Cost Analyses of Automated and Face to Face Intelligence Testing

Two replication studies were reported and costs were compared for automated WAIS testing versus face to face WAIS testing. Experiment I replicated the Elwood & Griffin (in press) study. Two sessions of automated WAIS testing indicated high test retest reliabilities for intelligence measures (VIQ 0.94, PIQ 0.95 and FSIQ 0.97), and moderately high rs for some non-IQ measures of WAIS responses. The study was interpreted as a successful replication of the Elwood & Griffin (in press) experiment. Experiment II was interpreted as a successful replication of the Coons & Peacock (1959) study. Two sessions of face to face WAIS testing resulted in these test retest rs: VIQ 0·98, PIQ 0·94 and FSIQ 0·97. An analysis of the salary levels and manhours required for testing indicated that for each dollar spent for face to face WAIS testing by a Phi) psychologist, the same testing could be performed by a BA level technician for $0·51 and that a technician and clerk typist working together could administer and score the automated WAIS for $0·42.