CN104166152B - A kind of detect particle accelerator line abnormal from triggering method - Google Patents

Abstract

The present invention provides a self-triggering method for detecting beam abnormality of a particle accelerator, comprising: Step S1, performing signal conditioning, sampling and digital signal processing on the electrode induction signals of 2 ^N electrodes of a button-type beam position probe, to obtain The turn-by-turn signal; step S2, obtaining the sum signal of the turn-by-turn signal in each period; calculating the difference between the sum signals of adjacent periods, and judging whether the difference reaches a preset threshold, and outputting the first trigger signal if reached; Step S3, select the turn-by-turn signal of the diagonal electrode to perform difference ratio sum operation; Step S4, perform discrete Fourier operation on the difference ratio sum result to obtain the beam current spectrum, and judge whether the beam current spectrum in the predetermined frequency range is consistent with the preset If the standard spectrum is consistent, if not, the second trigger signal will be output. The present invention can accurately and timely detect known events and instantaneous random abnormal events without external trigger signals, and provide corresponding trigger signals, thereby greatly improving data collection efficiency and intelligent level.

Description

A self-triggering method for detecting beam anomalies in particle accelerators

technical field

The invention relates to the field of accelerator physical beam diagnosis, and in particular designs a self-triggering method for detecting abnormality of particle accelerator beams.

Background technique

The beam measurement system is a very important part of the accelerator, and it plays a vital role in the machine research and normal operation of the accelerator. Among them, the beam position measurement system is one of the most important devices in the beam diagnosis, and it mainly consists of two parts: the button-type beam position probe at the front end and the beam position signal processor at the back end.

As shown in FIG. 1 , the beam position probe generally includes a vacuum chamber and four electrodes A, B, C and D symmetrically arranged on both sides of the vacuum chamber. The four electrodes output induction signals when the beam passes through the probe, and the induction signals are output to the beam position signal processor for conditioning, sampling and digital processing, and the obtained signal period is equal to the gyration period of the beam particles running around the accelerator storage ring (that is, turn-by-turn period) turn-by-turn signal.

The beam position signal processor starts to capture the induction signal after receiving the external trigger signal. When there are known external events, such as injecting particles (ie beam), etc., an external trigger signal will be provided; during normal operation, a fixed frequency trigger signal is input for data acquisition. However, when instantaneous and random abnormal events occur in the operation of the particle accelerator, such as beam drop, beam spectrum anomaly, etc., the signal processor in the external trigger mode cannot automatically capture the beam data before and after the anomaly for researchers to carry out machine analysis. research, resulting in the loss of valuable data. In summary, the dependence of the processor on external trigger signals limits its application value in machine operation and research.

Therefore, if the processor can use the internal signal processing algorithm to capture various meaningful events, including instantaneous and random abnormal operation events and known events, give trigger signals and store data before and after the event, it will greatly improve the beam current. The diagnostic level and efficiency provide powerful help for machine researchers to improve the performance of accelerators.

Contents of the invention

In view of the above technical problems, the present invention aims to provide a reliable and efficient self-triggering method for detecting beam anomalies in particle accelerators, which is convenient for users to timely discover unexpected situations such as beam drop and beam spectrum anomalies.

In order to achieve the above object, the present invention adopts the following technical solutions:

A self-triggering method for detecting beam anomalies in particle accelerators, comprising the following steps:

Step S1, performing signal conditioning, sampling and digital signal processing on the electrode induction signals output by the 2 ^N electrodes of the button-type beam position probe when the beam passes through the probe, so as to obtain the respective positions of the 2 ^N electrodes Corresponding turn-by-turn signal, the period of the turn-by-turn signal is equal to the turn-by-turn period of the beam particles running in the accelerator storage ring, wherein the button-type beam position probe includes a vacuum chamber and is respectively symmetrically arranged in the The 2 ^N electrodes on both sides of the vacuum chamber, wherein N is a natural number greater than 1;

Step S2, sequentially acquiring the sum signal of the turn-by-turn signals corresponding to the 2 ^N electrodes in each period; calculating the difference between the sum signals of two adjacent periods, and judging whether the difference reaches a preset threshold, if the threshold is reached, a first trigger signal is output;

Step S3, selecting a pair of the turn-by-turn signals corresponding to the diagonal electrodes to perform a difference ratio sum operation to obtain beam current position information; and

Step S4, performing a discrete Fourier operation on the result of the difference ratio sum operation in step S3 to obtain a beam spectrum, and judging whether the beam spectrum in a predetermined frequency range is consistent with a preset standard spectrum , if inconsistent, output a second trigger signal.

Further, the self-triggering method also includes:

Step S5, storing a predetermined number of the turn-by-turn signals corresponding to the 2 ^N electrodes before and after outputting the first trigger signal and/or the second trigger signal.

Further, the step S2 includes: performing low-pass filtering on the sum signal of the turn-by-turn signals before calculating the difference between the sum signals of the turn-by-turn signals of two adjacent periods.

To sum up, the present invention can not only self-trigger when an abnormal spectrum event occurs, such as known events such as beam beam and magnet excitation, but also self-trigger when instantaneous random abnormal conditions such as beam drop occur, thereby greatly facilitating It enables the user to discover the abnormal situation of the beam current in time. In addition, by storing a predetermined number of lap-by-turn signals before and after triggering, it can also provide effective analysis data for researchers to conduct machine research and improve machine performance.

Description of drawings

Fig. 1 is the structural representation of the button type beam position probe that the present invention adopts;

Fig. 2 is a schematic diagram of the self-triggering method for detecting beam anomalies in particle accelerators according to the present invention.

detailed description

Below in conjunction with the drawings, preferred embodiments of the present invention are given and described in detail.

In the present invention, the self-triggering method for detecting the abnormality of the particle accelerator beam is realized by using a beam position probe (as shown in Figure 1) and a beam position signal processor (not shown), as shown in Figure 2, the method includes the following step:

Step S1, when the beam passes through the probe, the four electrodes A, B, C and D respectively output corresponding electrode induction signals to the beam position signal processor, and the beam position signal processor performs signal conditioning, sampling and digital signal After processing, the turn-by-turn signals corresponding to each electrode are respectively obtained, and the turn-by-turn signals refer to signals whose period is equal to the turn-by-turn period of the beam particles running in the storage ring of the beam adder;

Step S2, sequentially obtain the sum signal of the turn-by-turn signals corresponding to the four electrodes in each turn-by-turn period, and perform low-pass filtering on each sum signal to avoid false triggering caused by high-frequency noise signals; then calculate the two phase The difference between the sum signal of the adjacent cycle, and judge whether the difference reaches the preset threshold, if it reaches the threshold, then output the first trigger signal, that is, when the decrease of the sum signal suddenly reaches a certain threshold, it means that there is a drop If the bundle event occurs, a first trigger signal is sent to the user at the upper layer to prompt that the bundle is abnormal.

Step S3, through the beam position signal processor, the difference ratio sum operation is performed on the turn-by-turn signals corresponding to the electrodes A and C at the diagonal, that is, (A-C)/(A+C) is calculated to obtain the horizontal and vertical The beam position information of the component. The reason why the diagonal electrodes A and C are selected here is that the data sampled by the two diagonal electrodes A and C include both horizontal and vertical beam motions.

Obtaining beam position information through difference ratio sum operation is a commonly used technical means in the field, and will not be repeated here. It should be understood that in this embodiment, the electrode-by-turn signals output by electrodes B and D can also be used to perform difference ratio sum calculations, and when a probe with more electrodes (for example, 8 electrodes) is used, the two electrodes can also be used The difference ratio sum operation is performed on the turn-by-turn signals output by two diagonal electrodes to obtain the beam current position information.

Step S4, through the beam position signal processor, perform discrete Fourier operation (preferably fast Fourier transform FFT) on the result of the difference ratio and operation in step S3 to obtain the beam spectrum, and then judge the beam current in the predetermined frequency range Is the spectrum consistent with the preset standard spectrum? If not, it means that the spectrum is abnormal (for example, it may be caused by the beam, etc., that the spectral peak at the working point is different from the normal operation, or there is no signal at the position where there should be a peak) , a second trigger signal is sent to the user at the upper layer to prompt that the frequency spectrum anomaly occurs. Among them, the discrete Fourier transform is performed all the time to avoid missing abnormal events. In addition, the predetermined frequency segment here is preferably a frequency segment that is relatively sensitive to spectrum, for example, it is set as a frequency segment within a range of 0.05 of the normalized spectrum around the operating point.

Step S5, the four electrodes A, B, C and D correspond to a predetermined number before and after the output of the first trigger signal and/or the second trigger signal through the beam position signal processor (for example, select 1000 before and after each) Left and right) turn-by-turn signals are stored in the buffer FIFO, which provides effective analysis data for researchers to conduct machine research and improve machine performance.

From the above analysis, it can be known that the present invention can output self-triggering signals to upper-level users when events such as beam drop and spectrum anomaly occur, so it no longer depends on external input triggering signals, which facilitates users to discover beam anomalies in time; in addition, it can also save The data before and after the abnormal situation is available for user analysis and research.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can also be made to the above embodiments of the present invention, for example, motor drive can be replaced with handwheel drive. That is, all simple and equivalent changes and modifications made according to the claims and description of the application of the present invention fall within the protection scope of the claims of the present invention.

Claims (3)

1. one kind detect particle accelerator line abnormal from triggering method, it is characterised in that should comprise the following steps from triggering method:

Step S1,2 to button type beam position probe^NIndividual electrode electrode induced signal of output when line is by described probe carries out signal condition, sampling and Digital Signal Processing, to obtain described 2 respectively^NThe from coil to coil signal that individual electrode is each corresponding, the from coil to coil cycle that the cycle of described from coil to coil signal is run in accelerator storage rings equal to line particle, wherein, described button type beam position probe includes a vacuum chamber and be arranged on described the 2 of described vacuum chamber both sides with being respectively symmetrically^NIndividual electrode, wherein, N is the natural number more than 1；

Step S2, obtains described 2 in each cycle successively^NDescribed from coil to coil signal corresponding to individual electrode and signal；Calculate the difference of the described and signal of two adjacent periods, and judge whether described difference reaches the threshold value preset, if reaching described threshold value, then output the first triggering signal；

Step S3, select the described from coil to coil signal being in for a pair corresponding to the described electrode at diagonal angle carry out differing from than and computing, to obtain beam position information；And

Step S4, the result of the described difference ratio in described step S3 and computing is carried out discrete fourier computing to obtain line frequency spectrum, and judge that whether the described line frequency spectrum in preset frequency section is consistent with default standard frequency spectrum, if it is inconsistent, output the second triggering signal.

2. detection particle accelerator line according to claim 1 abnormal from triggering method, it is characterised in that also should include from triggering method:

Step S5, stores described 2^NIndividual electrode is at the described first described from coil to coil signal triggering predetermined quantity corresponding before signal and/or second triggers signal output and after output.

3. detection particle accelerator line according to claim 1 abnormal from triggering method, it is characterized in that, described step S2 includes: calculate two adjacent periods described from coil to coil signal described in and signal difference before, to described from coil to coil signal and signal carry out low-pass filtering.