Squirrel-cage photomultiplier base design for measurement of nanosecond fluorescence decays

Abstract

Pommersheim and Chandra (1975) present analytical solutions for the general problem of the optimal policy of batch reactor operation (and tubular reactor operation when catalyst with no slip moves with the reaction fluid) for catalyst decay rates which depend on temperature, activity and concentration.The optimal temperature and corresponding concentration and activity formulas which they present are valid whenever the Legendre-Clebsch (L-C) condition is obeyed. They list three other criteria which they claim are equiualent to the criterion employed by Szepe and Levenspiel (1968) for the case of concentration independent decay. This is criterion (i) ofTable 1, which requires minimizing the final concentration (CAf), or maximizing the final conversion, for fixed run times (t,) and desired final activities (uf).The entire problem is shown in Table 1 with all four criteria stated. Solutions for the optimal policy can be shown to be identical for all four criteria. But for the optimal policy equations to be valid, the appropriate L-C conditions must be shown not to be violated. The L-C conditions may be different for these criteria, as they are derived employing the transversality conditions. The purpose of this note is to elucidate these restrictions on optimal temperature policies for the problem discussed by Pommersheim and Chandra and by example to further define the ranges of applicability of their solution. NTH ORDER SINGLE IRREVERSIBLE REACTIONThe reaction and activity rate functions considered are rA = KA am CAn respectively, can be shown to the independent of the nature of the criteria which specifies the Legendre-Clebsch condition. In order that Equation (2)-(4) specify optimal profiles, the L-C Functions* C.4 (t), 4 t h Y(t)Constraints 6 = C.4 + r.4 (C.!, a, Y) = 0 6 2 = a' + 6 (C,, a, y) = 0 End Conditions and Objectitje FunctionsCriterion (i) Criterion (ii) Criterion (iii) Criterion (iv)

Radiative Lifetimes of Eu i , ii , and iii and Transition Probabilities of Eu i

“…The base of the PMT is carefully wired for low inductance to maintain the response time of the tube. Bypass capacitors are added to maintain good linearity up to 10 mA peak anode current, and damping resistors are used to minimize ringing (Harris, Lytle, & McCain 1976). The digitizer has an analog bandwidth of 1 GHz.…”

Quantitative Laser-Induced Fluorescence Measurements and Modeling of Nitric Oxide in High-Pressure (6–15 Atm) Counterflow Diffusion Flames

“…The detector is a Hamamatsu R108UH-HA photomultiplier tube that is optimized for temporal resolution of the fluoescence signal (Harris et al, 1976). The broadband fluorescence signal encompasses a spectral width of $3 nm and is detected over a spectral region centered at $236 nm, corresponding to the g(0,1) band of NO.…”

Summer Research Program - 1996 Summer Research Extension Program. Volume 4B, Wright Laboratory

“…The PMT dynode circuitry is designed for fast response and has been described in detail previously. 54 The pulsed output from the PMT is directed to the digital oscilloscope and commercial software provided with the oscilloscope is used to carry out all data acquisition. The excited-state fluorescence lifetime was determined from a linearized, logarithmic plot of the excited-state decay trace as described elsewhere.…”