BNMR: Histograms and Scalers

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Introduction

In the frontend, data is read from the VME scaler(s) (SIS3801 or SIS3820) and saved in histograms. The number of histograms is greater than the number of active scaler channels. For example, some scaler data are saved in separate histograms according to the helicity. In the case of Type 1 runs, the histograms are sent every cycle, whereas for Type 2 the histograms are accumulated in the frontend memory, and sent every few minutes. A data logger running on the host computer saves the data onto disk. The data is handled differently for Type 1 and Type 2 runs. For Type 1 runs, the data are saved in a MIDAS file by mlogger, and converted to MUD format by mdarc. For Type 2 runs, mdarc saved the data directly in a MUD file, and no MIDAS file is produced.

The histograms and data logging will therefore be described separately for Type 1 and Type 2 runs.

Front-end histograms and Cycle Scalers

Scaler Channels : Hardware Connections

Currently,

• experiment bnmr has two SIS3801 scalers
• experiment bnqr has one SIS3820 scaler

NOTE

The sis3820 scaler is needed for bnqr alpha mode as it has a larger buffer and greater resolution.

BNMR

Table 1 : BNMR Scaler A Channels

Scaler	Module	Channel	Contents
A	SIS3801	1	Front scalers (16 segments summed in hardware)
		2	Front scalers (16 segments summed in hardware)
Total number of real scaler inputs : 2

Table 2 : BNMR Scaler B Channels

Scaler	Module	Channel	Contents
B	SIS3801	1	Scaler Internal Clock (not connected)
		2	Fluorescence Monitor (not used)
		3,4	Polarimeter counters (2)
		5,6,7,8	Neutral Beam Forwards counters (4)
		9,10,11,12	Neutral Beam Backwards counters (4)
Total number of real scaler inputs : 12

BNQR

Table 3 : BNQR Scaler B Channels

Scaler	Module	Channel	Contents
B	SIS3820 *	1	Scaler Internal Clock (not connected)
		17	Fluorescence Monitor (not used)
		18,19	Polarimeter counters (2)
		20	Neutral Beam Forwards counter (summed in hardware)
		21	Neutral Beam Backwards counter (summed in hardware)
		22,23,24,25	Alpha Counters
Total number of real scaler inputs : 10

NOTE

* SIS3820 module has ECL inputs 1-16, NIM 17-32. Therefore BNQR's input channel start at 17 (NIM).

Midas histograms built in the frontend

Type 1

Only includes data from last cycle.

Table 4: Scaler A histograms (bnmr only)

Scaler A	Histogram no.	Midas Bankname
sum Back scalers	h0	HIBP
sum Front scalers	h1	HIFP
userbits	h2	UBIT
Total number of BNMR Scaler A histograms: 3

Table 5 : Scaler B histograms (bnmr)

Scaler B	Histogram no.	Midas Bankname
sum scaler B (scaler clock)	h3	HM00
sum scaler B (fluorescence mon)	h4	HM01
sum scaler B (pol monitor 1)	h5	HM02
sum scaler B 3 (pol monitor 2)	h6	HM03
sum scaler B (Backwards  neutral beam monitors)	h7	HM04
sum scaler B (Forwards  neutral beam monitors)	h8	HM05
Total number of BNMR Scaler B histograms: 6

Total number of histograms from both scalers: 9 bnmr

Table 6 : Scaler B histograms (bnqr)

Scaler B	Histogram no.	Midas Bankname
sum scaler B (scaler clock)	h1	HM00
sum scaler B (fluorescence mon)	h2	HM01
sum scaler B (pol monitor 1)	h3	HM02
sum scaler B 3 (pol monitor 2)	h4	HM03
sum scaler B (Backwards  neutral beam monitors)	h5	HM04
sum scaler B (Forwards  neutral beam monitors)	h6	HM05
userbits	h7	UBIT**
Total number of BNQR histograms: 7
Alpha mode (1h) only
Alpha1	h7	HM06
Alpha2	h8	HM07
Alpha3	h9	HM08
Alpha4	h10	HM09
userbits	h11	UBIT **
Total number of BNQR histograms (Alpha mode): 11

NOTE

** Userbit bank is always the final bank

Type 2

For Type 2 (TD style), Midas histograms are built in the PPC frontend.

Histograms accumulate through the run

4 histograms from Scaler A:       
10 Histograms from Scaler B:
Total histograms  : 10 for BNQR, 14 for BNMR
  Table 7: Scaler A histograms (bnmr only)

Contents	Helicity	Scaler	Bank Name	Histogram Name
Back Scalers +	1	A	HIBP	B+
Front Scalers +	1	A	HIFP	F+
Back Scalers -	0	A	HIBN	B-
Front Scalers -	0	A	HIFN	F-

Table 8: Scaler B histograms (bnmr and bnqr)

Contents	Helicity	Scaler	Bank Name	Histogram Name
Reference Ticks	n/a	B	HMF1	Const
Fluorescence monitor	n/a	B	HMF2	FluM2
Polarimeter Left +	1	B	HMLP	L+
Polarimeter Right +	1	B	HMRP	R+
Polarimeter Left -	0	b	HMLN	L-
Polarimater Right  -	0	B	HMRN	R-
Neutral Beam Backwards +	1	B	HMBP	NBMB+
Neutral Beam Forwards +	1	B	HMFP	NBMF+
Neutral Beam Backwards -	0	B	HMBN	NBMB-
Neutral Beam Forwards -	0	B	HMFN	NBMF-

Table 9a: Scaler B histograms (bnmr and bnqr)

Contents	Helicity	Scaler	Bank Name	Histogram Name	BNMR	BNQR	BNQR Sample/Ref		BNQR Alpha Mode
Reference Ticks	n/a	B	HMF1	Const	Y	Y	Y		N
Fluorescence monitor	n/a	B	HMF2	FluM2	Y	Y	Y		N
Polarimeter Left +	1	B	HMLP	L+	Y	Y	Y	Ref	Y
Polarimeter Right +	1	B	HMRP	R+	Y	Y	Y	Ref	Y
Polarimeter Left -	0	b	HMLN	L-	Y	Y	Y	Ref	Y
Polarimater Right  -	0	B	HMRN	R-	Y	Y	Y	Ref	Y
Neutral Beam Backwards +	1	B	HMBP	NBMB+	Y	Y	Y	Ref	Y
Neutral Beam Forwards +	1	B	HMFP	NBMF+	Y	Y	Y	Ref	Y
Neutral Beam Backwards -	0	B	HMBN	NBMB-	Y	Y	Y	Ref	Y
Neutral Beam Forwards -	0	B	HMFN	NBMF-	Y	Y	Y	Ref	Y
Polarimeter Left +	1	B	HSLP		N	N	Y	Sample	N
Polarimeter Right +	1	B	HSRP		N	N	Y	Sample	N
Polarimeter Left -	0	B	HSLN		N	N	Y	Sample	N
Polarimeter Right -	0	B	HSRN		N	N	Y	Sample	N
Neutral Beam Backwards +	1	B	HSBP		N	N	Y	Sample	N
Neutral Beam Forwards +	1	B	HSFP		N	N	Y	Sample	N
Neutral Beam Backwards -	0	B	HMBN		N	N	Y	Sample	N
Neutral Beam Forwards -	0	B	HMFN		N	N	Y	Sample	N
Alpha1	1	B			N	N	N		Y

BNQR Alpha Mode (2h)

Alpha Mode (mode 2h) involves very long histograms with a very short bin width. To save space, histograms for the Reference Clock and Fluorescence Monitor are not saved. Furthermore, if the total number of bins requested for all histograms exceeds the maximum event size allowed by MIDAS, the histogram bin size will be reduced to 16 bits from 32 (the default). The histograms will be sent out from the frontend in 4 chunks, and reassembled by the data logger (mdarc) before being saved.