No abstract

No abstract

No abstract

No abstract

A description is given of a multichannel system for measuring the angular power distribution of synchrotron radiation in the electron-ring compressor at the Joint Institute for Nuclear Research. The detector is made from uncooled PbSe photoresistors and having linearly arranged 0.2 x l-mm 2 elements of overall length 120 ram. The system is intended for measuring the absolute number of electrons and for studying the dynamics of the electron (electron-ion) ring.In the case of electron ring accelerators such as the compressor of high-current annular bunches of low-energy electrons constructed at the Joint Institute for Nuclear Research (JINR) in the 1970s, the synchrotron radiation is a natural source of direct objective information on the compressed ring [1]. It provides a noncontacdng nondisturbing diagnnstie of the basic parameters of the electron (electron-ion) ring during and in the final stages of ks formation.The main aim of the work presented here is to increase the accuracy of measuring the number of electrous in an annular bunch compressed in the compressor. Synchrotron radiation characteristics such as the integral of its total flux and the angular dependence of its power distn'bution serve to obtain information on the absolute number of eleetrous (Nr in the annular bunch and the peak value of their oscillations along the ring axis (axial betatron oseillatious).The present article is devoted to a description of a coordinate detector which we developed in order to implement this aim. The detector is designed to measure the synchrotron radiation power and to investigate the angular distn'bution of this power as a function of the number of eleetrous in a bunch, their angular distribution, and also other factors (for example, the transverse dimension of the bunch, the presence of an ion component, etc.) during compression of the ring.In general the number of eleetrous N e is proportional to the total power radiated by the ring:where Usy is the electron signal at the synchrotron radiation detector, which is proportional to the radiation power in watts incident on the detector and recorded by it; Gsy is a geometric factor determln,-d by the geometry of the experiment and by the angular distribution of the synchrotron radiation power; S is a detector cah'bration factor, its integrated sensitivity, expressed in volts per unit incident power and measured in eal~ration experiments; w(X) is the radiation power from one electron; eCA) is the relative spectral sensitivity of the detector; ~) is the transmission factor of the intermediate optical media. The constant S is determined using a thermal source. It is well known that such a source has a spectral distribution of radiation power which is close to that of synchrotron radiation power. A tungsten n'bbon lamp cal~rated against an absolute black body was used as the standard source.The geometric factor is determined from the measured angular divergence of a beam of synchrotron radiation relative to the median plane of the annular bunch:G~ (e)= ~ j~(o)de,