Disclaimer |
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| Here are the Questions that you "the DØ Collaboration" made so far. | |
| The Questions are yours, the Answers and the Errors are mine. | |
| Some issues that require more lengthy explanation are dealt with in the page Issues and Clarifications | |
| Manuel I. Martin |
| Question | Isolated Electrons: are these real "electrons" with no other electrons near them - or do you mean no other objects near them? | |
| Answer | An "electron" is defined as an object made by a "track" that is associated with a PreShower "Cluster" (High or Low). For an electron to be isolated (Ie) it is sufficient that no other electrons are found in a wedge of 13.5º formed by the 4.5º wedge where the track of the electron is located and the two adjacent 4.5º wedges. Obviously, other objects other than electrons can be present in the mentioned 13.5º wedge. | |
| Question | Isolated Tracks, does this mean that there are no tracks in the 13.5º wedge or no tracks *and* no PS clusters ...? | |
| Answer | For an Track to be isolated (Ie) it is sufficient that no other tracks are found in a wedge of 13.5º formed by the 4.5º wedge where the track of the electron is located and the two adjacent 4.5º wedges. Obviously, other objects other than tracks can be present in the mentioned 13.5º wedge. | |
| Question | Is the data format sent to the STT the same as the data format sent to the CFT? | |
| Answer | Yes! I recognize that this implies that the STT gets some extra information (PS information) but to reformat the data stream is to costly in hardware. Besides, every track requires 32 bits of data when sent to the L2. | |
| Question | What is the significance of the "error code"? | |
| Answer | It provides information regarding what type of errors the Collector Board and/or the Broadcaster Board found in the data arriving to it. To use or not to use the information is up to the receiver. | |
| Question | ... and the "V" bit? | |
| Answer | The "V" bit is to
allow for the case when the bit string defining a track is all zeros.
V=1 implies that the data carried by the full word is a valid characterization of a track even if that is all zeros. V=0 implies that the bit string in this particular full word does not represents track information. Thus, ignore it! |
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| Question | # of tracks in Ptn: do these numbers reflect the truncated list that are stored in the data section below - or do they reflect the original counts? | |
| Answer | The # of tracks Ptn that are sent to the L2CFTpp are the ones corresponding to the truncated list sent in the same transmission. These values are sent as part of the Header and are to simplify the work of the L2CFTpp. | |
| Question | It seems that L1CTT will after all NOT generate a track number to identify each track uniquely. How do we match tracks a L2CTT ? | |
| Answer | I do not quite understand the issue. Both the L2CFTpp and the L2STTpp get information about the origin of the tracks. The data format shown on page 27 has two fields dedicated to this: the "TK Sector Address" gives the information about the 4.5º sector where the track was found, the "Relative F ..." combined with the Pt information uniquely identifies the track within the sector. Although it is possible for one PreProcessor to receive less number of tracks than the other (truncation issues) the difference is in the lower Pt ranges and is expected to be minimal. Nevertheless, I have been asking for a student to work with me to make MC analysis but no response yet. To fully understand the truncation scheme is important!! | |
| Question | The TIOCT terms would be nice if ... how is it envisaged [w]hat they will do? | |
| Answer | I think that knowledge of F separation of tracks or track clusters is important | |
| Question | In the L2CPS Axial and Stereo transfers does not the control bit (V) make the Low Thrsh. bit redundant? i.e. V=1 implies a Low Thresh.. Could this be replaced by an isolation bit thereby giving additional flexibility with no bit cost? | |
| Answer | Yes, you are right for the L2CPS Axial but the Stereo case does not have a "V" bit. The meaning of the "V" bit could be changed. | |
| Question | ... why emphasize isolated electrons? | |
| Answer | We could provide information about isolated tracks only. This is up to the Trigger Group. | |
| Question | Does the COL board [in the CFT/CPS Axial] compute the relative address of the highest Pt sector within the octant? | |
| Answer | Yes for L1, no for L2. | |
| Question | ... Should priority be given to tracks with a PS match? Of the 24 allowed tracks, ensure that track-PS matches are retained, then order by Pt and finally by F. | |
| Answer | Probably but ... at this moment it looks like we do not have the hardware resources to use more than a single parameter for truncation. I will keep trying! | |
| Question | ... is it possible to modify the truncation scheme in F to alternate between hi-phi and low-phi. | |
| Answer | Yes. The Trigger group must decide. | |
| Question | The question to you -- the shippers and receivers of Level 1 AND/OR terms: Is there a limitation on the number of groups of 16 terms that can be sent or received from any Level 1 Trigger manager? | |
| Answer | Yes. The Broadcaster Board sends a set of 96 bits to the Trigger Manager. in turn the Trigger Manager sends a set of 32 bits to the Trigger Framework. I think it is possible to increase the number of cables out from the TM but I am not sure. This is a question for Ken. | |
| Question | Is there any restriction on how many 16 bit groups the L1 Trigger Manager can send from CTT? Or is this a question for Ken Johns? | |
| Answer | Yes. This is a question for Ken. | |
| Question | Is there any restriction on how many 16 bit groups the L1 Trigger Manager can send from CTT? Or is this a question for Ken Johns? | |
| Answer | Yes. This is a question for Ken. | |
| Question | My reading of the Digital Board Transition Card (aka Signal Distribution Card) is that it can send up to 4 LVDS and two of either FSCL or Glink. We already call for one Glink to Level 3, and one FSCL to the Trigger Manager. Thus it seems that to feed two TM's, we would require a splitter. Or is it possible to provide the full set of 96 terms sent by the CTT axial broadcaster to two TM's across the trigger manager crate backplane? Is this correct? Is it doable? Is space an issue (extra TM cards and splitter) | |
| Answer | It will be necessary to split the signal. As far as I know, the m system has designed a two way splitter that could be used here. | |
| Question | My reading of the Digital Board Transition Card (aka Signal Distribution Card) is that it can send up to 4 LVDS and two of either FSCL or Glink. We already call for one Glink to Level 3, and one FSCL to the Trigger Manager. Thus it seems that to feed two TM's, we would require a splitter. Or is it possible to provide the full set of 96 terms sent by the CTT axial broadcaster to two TM's across the trigger manager crate backplane? Is this correct? Is it doable? Is space an issue (extra TM cards and splitter) | |
| Answer | It will be necessary to split the signal. As far as I know, the m system has designed a two way splitter that could be used here. | |
| Copyright © 1999 | This Home Page was created by Manuel I. Martin,Tuesday, June 08, 1999 | |