Abstract: A light sheet microscope includes an irradiation optical system, a detection optical system, and a photodetector. The irradiation optical system includes a wavelength sweep light source which outputs light of which a wavelength changes with time as excitation light, a spectroscopic element on which the excitation light output from the wavelength sweep light source is incident and which emits the excitation light at an emission angle corresponding to a wavelength of the excitation light, a relay optical system which includes a cylindrical lens on which the excitation light emitted from the spectroscopic element is incident at an incident angle corresponding to the emission angle, and a first objective lens which condenses the excitation light guided by the relay optical system and irradiates the sample with the excitation light having a sheet shape.

Abstract: Provided are isoelectric point(pI) markers for isoelectric focusing with fluorescence detection. The markers are fluorescence-labeled oligopeptides which comprise a fluorescence dye bonded chemically to the amino group of N-terminal amino acid of oligopeptide. The marker shows its unique and narrow pI band(peak) in electrophoresis or isoelectric focusing. The markers can be designed to have appropriate pI value, and cover wide range of pI (3<pI<11). Further, the markers have good storage stability. The markers can be preferably applied to the capillary isoelectric focusing with fluorescence detection due to their sharp and narrow band with strong emitted fluorescence.

Abstract: When incident light is incident to a photodetector, photoelectrons are emitted therefrom and then multiplied to output an electric current signal. This current signal is integrated over a predetermined period of time in an integrator to be converted to a voltage signal. This voltage signal is converted to a digital signal by an AD converter. This digital signal is supplied to a histogramming memory, which generates a pulse height distribution of voltage signal. Based on a pulse height distribution N(h) generated with incidence of measurement-object light to the photodetector, a pulse height distribution of single photoelectron events p.sub.1 (h) generated by a generator of pulse height distribution of single photoelectron events, and pulse height distributions of k-photoelectron events p.sub.k (h) (k=2, 3, . . .

Abstract: When incident light is incident to a photodetector, photoelectrons are emitted and multiplied in each of incident zones whereby a plurality of current signals are output. These current signals each are processed to estimate a distribution or a mean value of numbers of photoelectrons generated in each incident zone. Then estimated based on the estimate values of respective incident zones is the number of photoelectrons emitted from the entire photoelectric conversion surface. In this way the intensity of incident light is measured with accuracy.