Dear Dr. Didier,
I need to simulate DTL tank tilt along one transverse direction which is our practical scenario. There is a tilt in tank in the transverse direction perpendicular to stems of about 0.023 deg. In TraceWin, such an error doesn't exist. Could you please suggest how to go about carrying out this kind of error simulation?
Best Regards,
Shweta Roy
BARC
Mumbai
DTL tank tilt error
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Shweta Roy - Beginner
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Shweta Roy
- Beginner
- Posts: 5
- Joined: Mon 8 Dec 2025 10:14
- Country:
India (in)
Re: DTL tank tilt error
Post
by Shweta Roy »
Dear Didier,
Thanks for your response! However, as much as I understand DTL_CEL line is not affected by cavity misalignment errors. They are affected by field errors only. Please correct me if I am wrong. I have already given coupled quad error, but am not able to tilt the RF gaps as per my requirement.
Best Regards,
Shweta.
Thanks for your response! However, as much as I understand DTL_CEL line is not affected by cavity misalignment errors. They are affected by field errors only. Please correct me if I am wrong. I have already given coupled quad error, but am not able to tilt the RF gaps as per my requirement.
Best Regards,
Shweta.
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Shweta Roy
- Beginner
- Posts: 5
- Joined: Mon 8 Dec 2025 10:14
- Country:
India (in)
Re: DTL tank tilt error
Post
by Shweta Roy »
Another doubt is that when i give quad tilt about x in DTL, the error data file does contain the tilt but also shows non zero x displacement error. Why is it so?
Re: DTL tank tilt error
Dear Shweta,
Sorry for the confusion, it is indeed the ERROR_QUAD_CPL_XXXX command that must be used to apply a tilt to a DTL_CEL element and no other.
If you apply a tilt to an set of elements, this also generates a position error relative to the ideal axis. This is normal, as the beam no longer enters on axis=0 at the entrance of the set of tilted elements. If I didn't also apply displacements, coupling sequences of elements would have no particular effect due to coupling.
Regards,
Didier
Sorry for the confusion, it is indeed the ERROR_QUAD_CPL_XXXX command that must be used to apply a tilt to a DTL_CEL element and no other.
If you apply a tilt to an set of elements, this also generates a position error relative to the ideal axis. This is normal, as the beam no longer enters on axis=0 at the entrance of the set of tilted elements. If I didn't also apply displacements, coupling sequences of elements would have no particular effect due to coupling.
Regards,
Didier
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Shweta Roy
- Beginner
- Posts: 5
- Joined: Mon 8 Dec 2025 10:14
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India (in)
Re: DTL tank tilt error
Post
by Shweta Roy »
Dear Didier,
Can you please elaborate how do you get this displacement error values because as much as I understand the first quadrupole should have pure rotation error. Second and subsequent quads may have displacement error. Also a rotation about x axis will create displacement in y direction. But in my error data file it is in x only.
Best Regards,
Shweta
Can you please elaborate how do you get this displacement error values because as much as I understand the first quadrupole should have pure rotation error. Second and subsequent quads may have displacement error. Also a rotation about x axis will create displacement in y direction. But in my error data file it is in x only.
Best Regards,
Shweta
Re: DTL tank tilt error
Dear Sweta,
An angle error in X corresponds to a tilt in the horizontal direction. I admit it's a little counterintuitive, but that's how it's always been.
So, if I make a tilt error of 1° on a 5 m long tank, it should move the head by sin(1°)*(5/2), or -44 mm at the input and +44 mm at the output, and obviously 0 in the middle and progressive values for the other DTL cells.
Regards,
Didier
An angle error in X corresponds to a tilt in the horizontal direction. I admit it's a little counterintuitive, but that's how it's always been.
So, if I make a tilt error of 1° on a 5 m long tank, it should move the head by sin(1°)*(5/2), or -44 mm at the input and +44 mm at the output, and obviously 0 in the middle and progressive values for the other DTL cells.
Regards,
Didier
-
Shweta Roy
- Beginner
- Posts: 5
- Joined: Mon 8 Dec 2025 10:14
- Country:
India (in)
Re: DTL tank tilt error
Post
by Shweta Roy »
Dear Didier,
Does that mean when I give coupled quad error, all quads are rotated about an axis passing through the center of the tank and not the center of individual quad? I was assuming that the center of the first quad falls on beam axis, and rest all are rotated by the given tilt. But now it appears, that the center of the tank is on beam axis, and half tank is rotated to the left and the other half to the right.
Best Regards,
Shweta.
Does that mean when I give coupled quad error, all quads are rotated about an axis passing through the center of the tank and not the center of individual quad? I was assuming that the center of the first quad falls on beam axis, and rest all are rotated by the given tilt. But now it appears, that the center of the tank is on beam axis, and half tank is rotated to the left and the other half to the right.
Best Regards,
Shweta.